Fix: TypeError: Converting circular structure to JSON
Fix 'Converting circular structure to JSON' with a replacer function, and find the real source: DOM nodes, Mongoose documents, or Express request objects.
Tag: debugging
611 articles
RSSFix: Error: spawn ENOENT (Node.js child_process)
Fix Node.js 'Error: spawn ENOENT' from child_process.spawn(): PATH resolution, the Windows .cmd/.bat problem, and why shell: true is now discouraged (DEP0190).
Fix: TypeError: Cannot destructure property 'x' of 'y' as it is undefined
Fix JavaScript 'Cannot destructure property of undefined' from a missing argument, a failed API response, or optional chaining that doesn't prevent it.
Fix: Cannot set headers after they are sent to the client
Fix Node.js/Express 'Cannot set headers after they are sent to the client', usually a missing return, double next(), or a duplicate response.
Fix: TypeError: fetch failed (Node.js)
Fix Node.js 'TypeError: fetch failed' by reading error.cause to find what really failed: DNS, a refused connection, a timeout, or a bad certificate.
Fix: TypeError: Failed to fetch (JavaScript, Browser)
Fix 'TypeError: Failed to fetch' by telling apart CORS, mixed content, an ad blocker, and being offline using the browser's Network tab, not the JS error alone.
Fix: Error [ERR_REQUIRE_ESM]: require() of ES Module not supported
Fix Node.js 'Error [ERR_REQUIRE_ESM]: require() of ES Module not supported' by checking your Node version, using dynamic import(), or converting to ESM.
Fix: RangeError: Maximum call stack size exceeded (JavaScript)
Fix JavaScript 'RangeError: Maximum call stack size exceeded': find the runaway recursion, add a base case, fix accidental self-reference, and convert deep recursion to iteration.
Fix: listen EADDRINUSE: address already in use (Node.js)
Fix Node.js 'listen EADDRINUSE: address already in use': find and kill the process on the port (macOS, Linux, Windows), or run your server on a different port.
Fix: joblib Not Working — Parallel Backends, Memory Cache, and Pickling Errors
How to fix joblib errors — Parallel n_jobs slower than expected, Memory cache miss, backend loky vs threading vs multiprocessing, pickling lambda not supported, dump load file size, and pytest interference.
Fix: Marshmallow Not Working — Schema Errors, Load vs Dump, and Field Validation
How to fix Marshmallow errors — Schema not validated on dump, ValidationError messages format, unknown field handling, missing vs default, post_load object construction, and Marshmallow 3 to 4 migration.
Fix: Pipenv Not Working — Lock File Generation, Shell Activation, and Dependency Resolution
How to fix Pipenv errors — pipenv lock takes forever, Pipfile.lock not generated, shell activation broken, no virtualenv created, dependency conflict, and migration to uv or Poetry.
Fix: HTTPie Not Working — JSON Body, Authentication, and Session Errors
How to fix HTTPie errors — installation collision with httpie-cli, JSON body interpretation, multipart form data, OAuth bearer token, persistent sessions, SSL verification skip, and download mode.
Fix: Copier Not Working — Template Updates, Question Conditions, and Migrations
How to fix Copier errors — copier.yml not found, conditional questions not appearing, update breaks generated project, migrations between versions, Jinja vs YAML escaping, and answers file conflict.
Fix: Cookiecutter Not Working — Template Errors, Variable Substitution, and Hook Failures
How to fix Cookiecutter errors — cookiecutter.json not found, variable substitution failed Jinja2, pre/post-generation hooks failed, no_input mode missing values, private repo authentication, and copier vs cookiecutter.
Fix: scalene Not Working — Web UI, GPU Profiling, and AI Suggestion Errors
How to fix scalene errors — scalene command not found, web UI port conflict, no GPU detected, profile.json empty, AI optimize requires OpenAI key, native code not attributed, and Jupyter integration.
Fix: py-spy Not Working — Attach Permission, Empty Output, and Native Frame Errors
How to fix py-spy errors — Operation not permitted ptrace, flamegraph blank, missing native code frames, top mode shows no Python frames, dump command empty, and subprocess inheritance.
Fix: Litestar Not Working — Dependency Injection, msgspec Validation, and Controller Setup
How to fix Litestar errors — Starlite to Litestar migration, Dependency injection scope, controller route not found, msgspec validation differs from Pydantic, lifespan handler setup, and OpenAPI generation.
Fix: memray Not Working — Tracking Errors, Flamegraph Empty, and Native Allocations
How to fix memray errors — memray run command not found, flamegraph shows no data, native allocations not tracked, live mode TUI broken, attach to running process fails, and pytest integration.
Fix: msgspec Not Working — Struct Definition, Type Validation, and JSON/MessagePack Encoding
How to fix msgspec errors — Struct field type not supported, ValidationError on decode, msgspec vs Pydantic differences, custom type hooks, frozen Struct mutation, and JSON Schema generation.
Fix: attrs Not Working — Slots Conflict, Validator Errors, and dataclasses Migration
How to fix attrs errors — attrs.define vs attr.s API confusion, __slots__ inheritance issues, validator not running on assignment, converter type narrowing, cattrs structuring failed, and difference from dataclasses.
Fix: Peewee Not Working — Connection Pooling, Field Errors, and Migration Setup
How to fix Peewee errors — OperationalError database is locked, connection already open, field type mismatch, model meta database missing, N+1 queries, and peewee-migrate setup.
Fix: Tortoise ORM Not Working — Model Registration, Async Init, and Relationship Errors
How to fix Tortoise ORM errors — Tortoise.init not called, no module imported model, fetch_related missing, aerich migration setup, FastAPI integration patterns, and ConfigurationError missing connection.
Fix: conda Not Working — Solver Hangs, Channel Conflicts, and Environment Activation
How to fix conda errors — solving environment takes hours, channel conflicts conda-forge vs defaults, CondaSSLError, conda activate not working in shell, pip and conda mixing breaking env, and mamba/libmamba solver.
Fix: psycopg Not Working — psycopg2 to psycopg3 Migration, Connection Pool, and Async Errors
How to fix psycopg errors — psycopg2 to psycopg 3 import migration, connection pool setup, row factory tuple vs dict, COPY protocol changes, async psycopg pool, server-side cursor confusion, and binary mode performance.
Fix: SQLModel Not Working — table=True Confusion, Relationship Loading, and Session Errors
How to fix SQLModel errors — table not created without table=True, relationship not eager-loaded MissingGreenlet, AttributeError on lazy attribute, mixing Pydantic and Table classes, Optional vs default None, and async session setup.
Fix: Alembic Not Working — Autogenerate Missing Changes, Multiple Heads, and Migration Conflicts
How to fix Alembic errors — autogenerate not detecting model changes, Multiple head revisions, can't locate revision, downgrade fails, async engine support, and database URL configuration.
Fix: asyncpg Not Working — Connection Pool, Prepared Statements, and Transaction Errors
How to fix asyncpg errors — connection refused localhost 5432, pool exhausted timeout, prepared statement does not exist, type codec not registered, JSON automatic conversion, and transaction rollback on exception.
Fix: PDM Not Working — Lock File Errors, PEP 582 Confusion, and Script Issues
How to fix PDM errors — pdm install fails resolving dependencies, lock file outdated warning, __pypackages__ vs venv confusion, pdm run script not found, build backend missing, and dependency groups setup.
Fix: freezegun Not Working — Datetime Not Frozen, Timezone Issues, and Async Tests
How to fix freezegun errors — freeze_time decorator not affecting datetime.now, timezone-aware datetime mismatch, time.time not frozen, async test time leak, third-party library still using real time, and tick parameter behavior.
Fix: Moto Not Working — Mock Decorator, Real AWS Calls Leaking, and v4 to v5 Migration
How to fix Moto errors — mock not activating, real AWS credentials used in tests, ImportError mock_s3 removed in v5, fixtures with multiple services, NoCredentialsError despite mock, and standalone server mode.
Fix: Hatch Not Working — Environment Errors, Build Backend, and pyproject.toml Issues
How to fix Hatch errors — hatch env create fails, scripts not found, build backend hatchling missing, version not detected, plugin install errors, and publishing to PyPI.
Fix: Nox Not Working — Session Errors, Virtualenv Backends, and Reuse Logic
How to fix Nox errors — no noxfile.py found, session not detected, virtualenv backend uv not installed, session.install fails outside virtualenv, parametrize matrix exploding, and reuse_venv confusion.
Fix: Milvus Not Working — Connection Errors, Schema Setup, and Index Build Failures
How to fix Milvus errors — pymilvus connection refused localhost 19530, collection schema mismatch, index not built before search, partition not found, embedded vs standalone vs cluster, and flush before search.
Fix: MkDocs Not Working — Material Theme, Navigation, and Plugin Errors
How to fix MkDocs errors — Config value 'theme' must be a string or dict, mkdocstrings not generating API docs, navigation pages missing, mkdocs serve port already in use, GitHub Pages deploy failed, and broken links not detected.
Fix: Weaviate Not Working — Client v4 Migration, Schema Setup, and Vectorizer Errors
How to fix Weaviate errors — client v3 to v4 migration breaking imports, schema creation property mismatch, vectorizer module not loaded, connection refused localhost 8080, batch import errors, and hybrid search alpha tuning.
Fix: Sphinx Not Working — Autodoc Import Errors, Theme Issues, and Cross-References
How to fix Sphinx errors — autodoc cannot import module, theme not found, intersphinx links broken, ReadTheDocs build failed, MyST markdown not rendering, and unknown directive in conf.py.
Fix: DVC Not Working — Remote Push Errors, Pipeline DAG Issues, and Git Integration
How to fix DVC errors — dvc push authentication failed, dvc pull file missing, pipeline stage not reproducing, cache out of disk space, dvc add vs dvc stage, conflict with git LFS, and S3/GCS remote setup.
Fix: Structlog Not Working — Processor Chain, Context Variables, and Stdlib Integration
How to fix Structlog errors — output is dict not JSON, context vars not propagating, stdlib logging not unified, async context loss, configure_once, KeyValueRenderer vs JSONRenderer, and async filtering.
Fix: Tenacity Not Working — Retries Not Firing, Exception Filters, and Async Support
How to fix Tenacity errors — retry decorator not retrying, stop_after_attempt vs stop_after_delay, retry_if_exception_type filter, async retry decorator, jitter for backoff, and RetryError unwrap original exception.
Fix: Pydantic Settings Not Working — Env Vars Not Loading, Nested Config, and v2 Migration
How to fix Pydantic Settings errors — environment variables not picked up, .env file not loaded, ValidationError missing field, nested model env vars, SettingsConfigDict required, secret files, and BaseSettings import.
Fix: Click Not Working — Group Setup, Context Passing, and Parameter Type Errors
How to fix Click errors — UsageError missing argument, Group has no command, ctx.obj not passing between commands, ParamType validation failed, BadOptionUsage no such option, pass_context required, and lazy loading groups.
Fix: Rich Not Working — Live Display Issues, Color in CI, and Console Configuration
How to fix Rich errors — colors not appearing in CI logs, Live display flickering, progress bar not updating, table column overflow, traceback install conflicts, and Console redirect issues.
Fix: Typer Not Working — Argument Errors, Autocomplete, and Subcommand Issues
How to fix Typer errors — type annotation required error, Optional argument parsing, boolean flag conventions, autocomplete installation failed, nested commands not found, and rich traceback disable.
Fix: aiohttp Not Working — Session Leaks, ClientTimeout, and Connector Errors
How to fix aiohttp errors — RuntimeError session is closed, ClientConnectorError connection refused, SSL verify failure, Unclosed client session warning, server websocket disconnect, and connector pool exhausted.
Fix: Apache Airflow Not Working — DAG Not Found, Task Failures, and Scheduler Issues
How to fix Apache Airflow errors — DAG not appearing in UI, ImportError preventing DAG load, task stuck in running or queued, scheduler not scheduling, XCom too large, connection not found, and database migration errors.
Fix: BeautifulSoup Not Working — Parser Errors, Encoding Issues, and find_all Returns Empty
How to fix BeautifulSoup errors — bs4.FeatureNotFound install lxml, find_all returns empty list, Unicode decode error, JavaScript-rendered content not found, select vs find_all confusion, and slow parsing on large HTML.
Fix: ChromaDB Not Working — Persistent Client, Collection Errors, and Embedding Function Issues
How to fix ChromaDB errors — persistent client not saving data, collection already exists error, dimension mismatch in embeddings, embedding function required, HTTP client connection refused, and memory growing unbounded.
Fix: CrewAI Not Working — Agent Delegation, Task Context, and LLM Configuration Errors
How to fix CrewAI errors — LLM not configured ValidationError, agent delegation loop, task context not passed between agents, tool output truncated, process hierarchical vs sequential, and memory not persisting across runs.
Fix: Dagster Not Working — Asset Loading, Resource Errors, and Daemon Issues
How to fix Dagster errors — asset not found in definitions, resource not defined, dagster daemon not running, sensor or schedule not firing, DagsterInvariantViolationError, and asset materialization failing.
Fix: Dash Not Working — Callback Errors, Pattern Matching, and State Management
How to fix Dash errors — circular dependency in callbacks, pattern matching callback not firing, missing attribute clientside_callback, DataTable filtering not working, clientside JavaScript errors, Input Output State confusion, and async callback delays.
Fix: Dask Not Working — Scheduler Errors, Out of Memory, and Delayed Not Computing
How to fix Dask errors — KilledWorker out of memory, client cannot connect to scheduler, delayed not computing, DataFrame partition size wrong, map_partitions TypeError, diagnostics dashboard not showing, and version mismatch.
Fix: dbt Not Working — ref() Not Found, Schema Mismatch, and Compilation Errors
How to fix dbt errors — ref() model not found, profile not found, database relation does not exist, incremental model schema mismatch requiring full-refresh, dbt deps failure, Jinja compilation errors, and test failures.
Fix: FAISS Not Working — Import Errors, Index Selection, and GPU Setup
How to fix FAISS errors — ImportError cannot import name swigfaiss, faiss-gpu vs faiss-cpu install, IndexFlatL2 slow on large data, IVF training required, index serialization write_index, and dimension mismatch.
Fix: Gradio Not Working — Share Link, Queue Timeout, and Component Errors
How to fix Gradio errors — share link not working, queue timeout, component not updating, Blocks layout mistakes, flagging permission denied, file upload size limit, and HuggingFace Spaces deployment failures.
Fix: Gunicorn Not Working — Worker Timeout, Boot Errors, and Signal Handling
How to fix Gunicorn errors — WORKER TIMEOUT killed, ImportError cannot import app, worker class not found, connection refused 502 behind nginx, graceful reload not working, and sync vs async worker selection.
Fix: httpx Not Working — Async Client, Timeout, and Connection Pool Errors
How to fix httpx errors — RuntimeError event loop is closed, ReadTimeout exception, ConnectionResetError, async client not closing properly, HTTP/2 not enabled, SSL verify failed, and proxy not working.
Fix: Hypothesis Not Working — Strategy Errors, Flaky Tests, and Shrinking Issues
How to fix Hypothesis errors — Unsatisfied assumption, Flaky test detected, HealthCheck data_too_large, strategy composition failing, example database stale, settings profile not found, and stateful testing errors.
Fix: Jupyter Notebook Not Working — Kernel Dead, Module Not Found, and Widget Errors
How to fix Jupyter errors — kernel fails to start or dies, ModuleNotFoundError despite pip install, matplotlib plots not showing, ipywidgets not rendering in JupyterLab, port already in use, and jupyter command not found.
Fix: LangGraph Not Working — State Errors, Checkpointer Setup, and Cyclic Graph Failures
How to fix LangGraph errors — state not updating between nodes, checkpointer thread_id required, StateGraph compile error, conditional edges not routing, streaming events missing, recursion limit exceeded, and interrupt handling.
Fix: LightGBM Not Working — Installation Errors, Categorical Features, and Training Issues
How to fix LightGBM errors — ImportError libomp libgomp not found, do not support special JSON characters in feature name, categorical feature index out of range, num_leaves vs max_depth overfitting, early stopping callback changes, and GPU build errors.
Fix: LlamaIndex Not Working — Import Errors, Vector Store Issues, and Query Engine Failures
How to fix LlamaIndex errors — ImportError llama_index.core module not found, ServiceContext deprecated use Settings instead, vector store index not persisting, query engine returns irrelevant results, and LlamaIndex 0.10 migration.
Fix: Locust Not Working — User Class Errors, Distributed Mode, and Throughput Issues
How to fix Locust errors — no locustfile found, User class not detected, worker connection refused, distributed mode throughput lower than single-node, StopUser exception, FastHttpUser vs HttpUser, and headless CSV reports.
Fix: Loguru Not Working — Missing Logs, Rotation Errors, and Multiprocessing Issues
How to fix Loguru errors — logs not appearing after logger.add, file rotation not working, enqueue required for multiprocessing, structured logging JSON, intercepting stdlib logging, and handler removal.
Fix: Matplotlib Not Working — Plots Not Showing, Blank Output, and Figure Layout Problems
How to fix Matplotlib errors — plot not displaying, blank figure, RuntimeError main thread not in main loop, tight_layout UserWarning, overlapping subplots, savefig saving blank image, backend errors, and figure/axes confusion.
Fix: MLflow Not Working — Tracking URI, Artifact Store, and Model Registry Errors
How to fix MLflow errors — no tracking server, artifact path not accessible, model version not found, experiment not found, MLFLOW_TRACKING_URI not set, autolog not recording metrics, and MLflow UI showing no runs.
Fix: NumPy Not Working — Broadcasting Error, dtype Mismatch, and Array Shape Problems
How to fix NumPy errors — ValueError operands could not be broadcast together, setting an array element with a sequence, integer overflow, axis confusion, view vs copy bugs, NaN handling, and NumPy 1.24+ removed type aliases.
Fix: ONNX Not Working — Conversion Errors, Runtime Provider Issues, and Dynamic Shape Problems
How to fix ONNX errors — torch.onnx.export unsupported operator, ONNX Runtime CUDA provider not found, InvalidArgument input shape mismatch, dynamic axes not working, IR version mismatch, and opset version conflicts.
Fix: OpenCV Not Working — imread Returns None, imshow Crash, and Color Channel Errors
How to fix OpenCV errors — cv2.imread returns None, imshow crashes on headless server, BGR vs RGB color mismatch, cannot open video capture, ImportError libGL not found, resize interpolation, and cv2.error assertion failed.
Fix: Optuna Not Working — Trial Pruned, Storage Errors, and Search Space Problems
How to fix Optuna errors — TrialPruned stops too early, RDB storage locked or not saving, suggest methods raise ValueError, parallel study workers deadlock, integration callbacks not reporting, and best trial not reproducible.
Fix: Pandera Not Working — Schema Validation Errors, DataFrame Types, and Lazy Mode
How to fix Pandera errors — SchemaError column not in DataFrame, dtype mismatch, Check failed, lazy validation not collecting errors, SchemaModel vs DataFrameModel API, Polars support, and coercion errors.
Fix: pgvector Not Working — Extension Install, Index Not Used, and Dimension Errors
How to fix pgvector errors — extension does not exist CREATE EXTENSION vector, dimension mismatch on insert, HNSW index not used slow queries, distance operator confusion, psycopg register adapter, and ivfflat vs hnsw selection.
Fix: Pillow PIL Not Working — Cannot Identify Image, Mode Errors, and EXIF Rotation
How to fix Pillow PIL errors — UnidentifiedImageError cannot identify image file, OSError cannot write mode RGBA as JPEG, EXIF orientation rotated wrong, decompression bomb warning, ImageDraw text rendering, and HEIF AVIF support missing.
Fix: Pinecone Not Working — Index Creation, Serverless vs Pod, and Python SDK v3 Migration
How to fix Pinecone errors — ApiException 401 unauthorized, index not found, dimension mismatch, serverless spec required, Python SDK v3 breaking changes, namespace confusion, and upsert rate limit 429.
Fix: Plotly Not Working — Figure Not Showing, Kaleido Export Errors, and Subplot Issues
How to fix Plotly errors — figure not rendering in Jupyter, ValueError must install Kaleido, static image export slow or crashing, subplot trace placement, update_layout not working, and offline vs online mode confusion.
Fix: Polars Not Working — AttributeError, InvalidOperationError, and ShapeError
How to fix Polars errors — AttributeError groupby not found, InvalidOperationError from Python lambdas, ShapeError broadcasting mismatch, lazy vs eager collect confusion, type casting failures, and ColumnNotFoundError in with_columns.
Fix: pre-commit Not Working — Hooks Not Running, Install Failures, and CI Issues
How to fix pre-commit errors — hooks not triggering on commit, pre-commit install failed, repo local hook not found, autoupdate not working, CI environment cache issues, and skip specific hooks.
Fix: Prefect Not Working — Flow Deployment, Worker Errors, and 2.x to 3.x Migration
How to fix Prefect errors — flow deployment not running, worker not picking up runs, PrefectHTTPStatusError cannot connect to API, task retries not working, state transitions stuck in Pending, and flow_run_name template not resolving.
Fix: PySpark Not Working — Java Heap Space, Serialization Errors, and OOM Exceptions
How to fix PySpark errors — Java heap space out of memory, PicklingError cannot serialize, py4j gateway exception, Spark session not found, partition skew causing slow shuffle, lazy evaluation confusion, and collect crashing driver.
Fix: Qdrant Not Working — Connection Errors, Collection Setup, and Filter Syntax Issues
How to fix Qdrant errors — connection refused to localhost 6333, collection not found create_collection, vector size mismatch, filter must match schema, payload index missing slow queries, and timeout on large batch uploads.
Fix: Ray Not Working — Cluster Init, Object Store Memory, and Actor Lifecycle Errors
How to fix Ray errors — ray.init connection refused, object store full ObjectStoreFullError, worker died unexpectedly, serialization PickleError for remote function, Ray Tune trials fail, Ray cluster version mismatch, and actor ReferenceError.
Fix: Ruff Not Working — Configuration Errors, Rule Selection, and Format vs Lint Confusion
How to fix Ruff errors — pyproject.toml configuration not applied, rule code unknown, ruff format vs ruff check confusion, ignore not working, per-file-ignores, line-length conflicts, and migrating from Flake8 Black isort.
Fix: SciPy Not Working — Sparse Matrix Errors, Optimization Convergence, and Import Issues
How to fix SciPy errors — ImportError cannot import name, sparse matrix deprecation warning, optimize.minimize did not converge, integrate.quad divergence, interpolate extrapolation, scipy.stats API changes, and Fortran compiler missing.
Fix: Seaborn Not Working — FutureWarning, FacetGrid Errors, and Figure-Level Confusion
How to fix Seaborn errors — FutureWarning use of palette without hue, figure-level vs axes-level function confusion, FacetGrid layout issues, tight_layout with seaborn, seaborn 0.13 breaking changes, and ci parameter deprecated.
Fix: Scrapy Not Working — Spider Crawl Returns Nothing, Robots.txt Blocked, and Pipeline Errors
How to fix Scrapy errors — spider yields no items, robots.txt blocking all requests, 403 forbidden response, AttributeError on response.css, item pipeline not processing, AsyncIO reactor errors, and middleware not running.
Fix: Selenium Not Working — WebDriver Errors, Element Not Found, and Timeout Issues
How to fix Selenium errors — WebDriverException session not created, NoSuchElementException element not found, StaleElementReferenceException, TimeoutException waiting for element, headless Chrome crashes, and driver version mismatch.
Fix: scikit-learn Not Working — NotFittedError, NaN Input, Pipeline, and ConvergenceWarning
How to fix scikit-learn errors — NotFittedError call fit before predict, ValueError Input contains NaN, could not convert string to float, Pipeline ColumnTransformer mistakes, cross-validation leakage, n_jobs hanging on Windows, and ConvergenceWarning.
Fix: Streamlit Not Working — Session State, Cache, and Rerun Problems
How to fix Streamlit errors — session state KeyError state not persisting, @st.cache deprecated migrate to cache_data cache_resource, file upload resetting, slow app loading on every interaction, secrets not loading, and widget rerun loops.
Fix: TensorFlow Not Working — OOM, Shape Mismatch, GPU Not Found, and Keras Errors
How to fix TensorFlow errors — GPU not detected CUDA library missing, ResourceExhaustedError OOM, InvalidArgumentError shape mismatch, NaN loss, @tf.function AutoGraph failures, and Keras 3 breaking changes in TF 2.16+.
Fix: Tox Not Working — Environment Creation, Config Errors, and Multi-Python Testing
How to fix Tox errors — ERROR cannot find Python interpreter, tox.ini config parsing error, allowlist_externals required, recreating environments slow, pyproject.toml integration, and matrix env selection.
Fix: Uvicorn Not Working — Worker Errors, Reload Issues, and Production Deployment
How to fix Uvicorn errors — Address already in use port binding, reload not detecting changes, SSL certificate errors, worker class with gunicorn, WebSocket disconnect, graceful shutdown, and proxy headers behind nginx.
Fix: vLLM Not Working — CUDA OOM, Model Loading, and API Server Errors
How to fix vLLM errors — CUDA out of memory during model load, tokenizer mismatch with HuggingFace, tensor parallel size does not match GPU count, KV cache exceeds memory, OpenAI API compatibility issues, and max_model_len too large.
Fix: Weights & Biases (wandb) Not Working — Login Errors, Init Hangs, and Sync Failures
How to fix wandb errors — API key not set login failed, wandb init hangs, offline mode sync, artifact upload failure, run not showing in dashboard, image logging size limit, and sweep agent not starting.
Fix: OpenAI Whisper Not Working — FFmpeg Missing, GPU Slow, and Language Detection Errors
How to fix Whisper errors — FFmpeg not found audio file load failed, CUDA out of memory on large model, slow CPU transcription, language detected incorrectly, hallucinations on silence, faster-whisper migration, and timestamp accuracy.
Fix: XGBoost Not Working — Feature Name Mismatch, GPU Errors, and Early Stopping Changes
How to fix XGBoost errors — feature names mismatch, XGBoostError GPU training fails, use_label_encoder deprecated, eval_metric warning, early stopping moved to callback, ValueError for DMatrix, and sklearn API confusion.
Fix: AWS CDK Not Working, Bootstrap Error, ROLLBACK_COMPLETE, and Deploy Failures
How to fix AWS CDK errors, cdk bootstrap required, stack in ROLLBACK_COMPLETE, asset bundling failed, CLI/library version mismatch, VPC lookup failing, and cross-stack export conflicts.
Fix: Deno PermissionDenied — Missing --allow-read, --allow-net, and Other Flags
How to fix Deno PermissionDenied (NotCapable in Deno 2) errors — the right permission flags, path-scoped permissions, deno.json permission sets, and the Deno.permissions API.
Fix: Fastify Not Working — 404, Plugin Encapsulation, and Schema Validation Errors
How to fix Fastify issues — route 404 from plugin encapsulation, reply already sent, FST_ERR_VALIDATION, request.body undefined, @fastify/cors, hooks not running, and TypeScript type inference.
Fix: Helm Not Working — Release Already Exists, Stuck Upgrade, and Values Not Applied
How to fix Helm 3 errors — release already exists, another operation is in progress, --set values not applied, nil pointer template errors, kubeVersion mismatch, hook failures, and ConfigMap changes not restarting pods.
Fix: Hugging Face Transformers Not Working — OSError, CUDA OOM, and Generation Errors
How to fix Hugging Face Transformers errors — OSError can't load tokenizer, gated repo access, CUDA out of memory with device_map auto, bitsandbytes not installed, tokenizer padding mismatch, pad_token_id warning, and LoRA adapter loading failures.
Fix: Kafka Consumer Not Receiving Messages, Connection Refused, and Rebalancing Errors
How to fix Apache Kafka issues — consumer not receiving messages, auto.offset.reset, Docker advertised.listeners, max.poll.interval.ms rebalancing, MessageSizeTooLargeException, and KafkaJS errors.
Fix: LangChain Python Not Working — ImportError, Pydantic, and Deprecated Classes
How to fix LangChain Python errors — ImportError from package split, Pydantic v2 compatibility, AgentExecutor deprecated, ConversationBufferMemory removed, LCEL output type mismatches, and tool calling failures.
Fix: Ollama Not Working — Connection Refused, Model Not Found, GPU Not Detected
How to fix Ollama errors — connection refused when the daemon isn't running, model not found, GPU not detected falling back to CPU, port 11434 already in use, VRAM exhausted, and API access from other machines.
Fix: OpenAI API Not Working — RateLimitError, 401, 429, and Connection Issues
How to fix OpenAI API errors — RateLimitError (429), AuthenticationError (401), APIConnectionError, context length exceeded, model not found, and SDK v0-to-v1 migration mistakes.
Fix: Puppeteer Not Working — Navigation Timeout, Chrome Not Found, and Target Closed
How to fix Puppeteer errors — navigation timeout exceeded, failed to launch browser process in Docker and CI, element not found, page crashed Target closed, memory leaks from unclosed pages, and waiting for dynamic content.
Fix: PyTorch Not Working — CUDA Out of Memory, Device Mismatch, and NaN Loss
How to fix PyTorch errors — CUDA out of memory, expected all tensors on same device, CUDA device-side assert triggered, torch.cuda.is_available() False, inplace gradient errors, DataLoader Windows crash, dtype mismatch, and NaN loss.
Fix: SQLAlchemy Not Working — DetachedInstanceError, Pool Exhausted, and MissingGreenlet
How to fix SQLAlchemy 2.x errors — DetachedInstanceError from lazy loading, QueuePool limit exceeded, MissingGreenlet in async context, N+1 queries, IntegrityError rollback, and Alembic migration failures.
Fix: uv Not Working — Command Not Found, Python Version Error, and Lock File Conflicts
How to fix uv errors — uv command not found after install, no Python interpreter found, uv run vs activate confusion, uv.lock merge conflicts, uv pip vs uv add, migrating from pip and Poetry, and workspace resolution failures.
Fix: Algolia Not Working — Search Returning No Results, Index Not Updating, or InstantSearch Errors
How to fix Algolia issues — indexing, search queries, InstantSearch setup, ranking configuration, facets, API key permissions, and Next.js integration.
Fix: Directus Not Working — API Returning 403, Items Not Appearing, or Flows Not Triggering
How to fix Directus issues — permissions, access policies, collections, REST and GraphQL APIs, file uploads, Flows automation, and self-hosted deployment.
Fix: Meilisearch Not Working — Search Returns No Results, Index Not Found, or API Key Errors
How to fix Meilisearch issues — index setup, document indexing, search configuration, filtering, facets, typo tolerance, and self-hosted deployment.
Fix: Nodemailer Not Working — Emails Not Sending, SMTP Auth Failing, or Gmail Blocking
How to fix Nodemailer issues — SMTP configuration, Gmail OAuth2, TLS errors, connection timeouts, email not delivered, and using with Next.js or Express.
Fix: Temporal Not Working — Workflows Not Starting, Activities Failing, or Worker Not Connecting
How to fix Temporal issues — worker setup, workflow and activity errors, schedule configuration, versioning, and self-hosted Temporal Server deployment.
Fix: Chakra UI Not Working — Provider Missing, Styles Not Applied, or Dark Mode Broken
How to fix Chakra UI v3 issues — ChakraProvider setup, color mode, theming, server-side rendering in Next.js, component styling, and common runtime errors.
Fix: PocketBase Not Working — Auth Failing, Real-time Subscriptions Broken, or Collection Rules Blocking Requests
How to fix PocketBase issues — authentication, collection access rules, real-time subscriptions, file uploads, relations, and self-hosted deployment.
Fix: Sanity Not Working — GROQ Queries Returning Nothing, CORS Errors, or Studio Not Loading
How to fix Sanity CMS issues — GROQ queries, CORS configuration, dataset permissions, image URLs, Portable Text, webhooks, and Next.js integration.
Fix: Strapi Not Working — API Returns 403, Content Not Appearing, or Plugin Errors
How to fix Strapi v5 issues — permissions, content types, REST and GraphQL APIs, media uploads, webhooks, plugins, and deployment configuration.
Fix: UploadThing Not Working — File Upload Failing, CORS Errors, or Route Not Found
How to fix UploadThing issues — file router configuration, Next.js App Router and Pages Router setup, CORS, file type restrictions, progress callbacks, and deployment.
Fix: Analog Not Working — Routes Not Loading, API Endpoints Failing, or Vite Build Errors
How to fix Analog (Angular meta-framework) issues — file-based routing, API routes with Nitro, content collections, server-side rendering, markdown pages, and deployment.
Fix: Angular SSR Not Working — Hydration Failing, Window Not Defined, or Build Errors
How to fix Angular Server-Side Rendering issues — @angular/ssr setup, hydration, platform detection, transfer state, route-level rendering, and deployment configuration.
Fix: Astro DB Not Working — Tables Not Found, Queries Failing, or Seed Data Missing
How to fix Astro DB issues — schema definition, seed data, queries with drizzle, local development, remote database sync, and Astro Studio integration.
Fix: Astro Actions Not Working — Form Submission Failing, Validation Errors Missing, or Return Type Wrong
How to fix Astro Actions issues — action definition, Zod validation, form handling, progressive enhancement, error handling, file uploads, and calling actions from client scripts.
Fix: Coolify Not Working — Deployment Failing, SSL Not Working, or Containers Not Starting
How to fix Coolify self-hosted PaaS issues — server setup, application deployment, Docker and Nixpacks builds, environment variables, SSL certificates, database provisioning, and GitHub integration.
Fix: Expo Router Not Working — Routes Not Matching, Layout Nesting Wrong, or Deep Links Failing
How to fix Expo Router issues — file-based routing, layout routes, dynamic segments, tabs and stack navigation, modal routes, authentication flows, and deep linking configuration.
Fix: NativeWind Not Working — Styles Not Applying, Dark Mode Broken, or Metro Bundler Errors
How to fix NativeWind issues — Tailwind CSS for React Native setup, Metro bundler configuration, className prop, dark mode, responsive styles, and Expo integration.
Fix: React Native Paper Not Working — Theme Not Applying, Icons Missing, or Components Unstyled
How to fix React Native Paper issues — PaperProvider setup, Material Design 3 theming, custom color schemes, icon configuration, dark mode, and Expo integration.
Fix: React Navigation Not Working — Screens Not Rendering, TypeScript Errors, or Gestures Broken
How to fix React Navigation issues — stack and tab navigator setup, TypeScript typing, deep linking, screen options, nested navigators, authentication flow, and performance optimization.
Fix: SolidStart Not Working — Routes Not Rendering, Server Functions Failing, or Hydration Errors
How to fix SolidStart issues — file-based routing, server functions, createAsync data loading, middleware, sessions, and deployment configuration.
Fix: Tamagui Not Working — Styles Not Applying, Compiler Errors, or Web/Native Mismatch
How to fix Tamagui UI kit issues — setup with Expo, theme tokens, styled components, animations, responsive props, media queries, and cross-platform rendering.
Fix: TanStack Start Not Working — Server Functions Failing, Routes Not Loading, or SSR Errors
How to fix TanStack Start issues — project setup, file-based routing, server functions with createServerFn, data loading, middleware, SSR hydration, and deployment configuration.
Fix: Vinxi Not Working — Dev Server Not Starting, Routes Not Matching, or Build Failing
How to fix Vinxi server framework issues — app configuration, routers, server functions, middleware, static assets, and deployment to different platforms.
Fix: Waku Not Working — Server Components Not Rendering, Client Components Not Interactive, or Build Errors
How to fix Waku React framework issues — RSC setup, server and client component patterns, data fetching, routing, layout system, and deployment configuration.
Fix: Wasp Not Working — Build Failing, Auth Not Working, or Operations Returning Empty
How to fix Wasp full-stack framework issues — main.wasp configuration, queries and actions, authentication setup, Prisma integration, job scheduling, and deployment.
Fix: AutoAnimate Not Working — Transitions Not Playing, List Items Not Animating, or React State Changes Ignored
How to fix @formkit/auto-animate issues — parent ref setup, React useAutoAnimate hook, Vue directive, animation customization, disabling for specific elements, and framework integration.
Fix: Better Auth Not Working — Login Failing, Session Null, or OAuth Callback Error
How to fix Better Auth issues — server and client setup, email/password and OAuth providers, session management, middleware protection, database adapters, and plugin configuration.
Fix: Blurhash Not Working — Placeholder Not Rendering, Encoding Failing, or Colors Wrong
How to fix Blurhash image placeholder issues — encoding with Sharp, decoding in React, canvas rendering, Next.js image placeholders, CSS blur fallback, and performance optimization.
Fix: BullMQ Not Working — Jobs Not Processing, Workers Not Starting, or Redis Connection Failing
How to fix BullMQ issues — queue and worker setup, Redis connection, job scheduling, retry strategies, concurrency, rate limiting, event listeners, and dashboard monitoring.
Fix: Changesets Not Working — Version Not Bumping, Changelog Empty, or GitHub Action Failing
How to fix @changesets/cli issues — changeset creation, version bumping, changelog generation, monorepo support, npm publishing, and GitHub Actions automation.
Fix: Clack Not Working — Prompts Not Displaying, Spinners Stuck, or Cancel Not Handled
How to fix @clack/prompts issues — interactive CLI prompts, spinners, multi-select, confirm dialogs, grouped tasks, cancellation handling, and building CLI tools with beautiful output.
Fix: Clerk Not Working — Auth Not Loading, Middleware Blocking, or User Data Missing
How to fix Clerk authentication issues — ClerkProvider setup, middleware configuration, useUser and useAuth hooks, server-side auth, webhook handling, and organization features.
Fix: cmdk Not Working — Command Palette Not Opening, Items Not Filtering, or Keyboard Navigation Broken
How to fix cmdk command palette issues — Dialog setup, custom filtering, groups and separators, keyboard shortcuts, async search, nested pages, and integration with shadcn/ui and Tailwind.
Fix: CodeMirror Not Working — Editor Not Rendering, Extensions Not Loading, or React State Out of Sync
How to fix CodeMirror 6 issues — basic setup, language and theme extensions, React integration, vim mode, collaborative editing, custom keybindings, and read-only mode.
Fix: Conform Not Working — Form Validation Not Triggering, Server Errors Missing, or Zod Schema Rejected
How to fix Conform form validation issues — useForm setup with Zod, server action integration, nested and array fields, file uploads, progressive enhancement, and Remix and Next.js usage.
Fix: Contentlayer Not Working — Content Not Generated, Types Missing, or Build Errors
How to fix Contentlayer and Contentlayer2 issues — content source configuration, document type definitions, MDX processing, computed fields, Next.js integration, and migration to alternatives.
Fix: Docusaurus Not Working — Build Failing, Sidebar Not Showing, or Plugin Errors
How to fix Docusaurus issues — docs and blog configuration, sidebar generation, custom theme components, plugin setup, MDX compatibility, search integration, and deployment.
Fix: ElectricSQL Not Working — Sync Not Starting, Shapes Empty, or Postgres Connection Failing
How to fix ElectricSQL issues — Postgres setup with logical replication, shape definitions, real-time sync to the client, React hooks, write-path through the server, and deployment configuration.
Fix: Embla Carousel Not Working — Slides Not Scrolling, Autoplay Not Starting, or Thumbnails Not Syncing
How to fix Embla Carousel issues — React setup, slide sizing, autoplay and navigation plugins, loop mode, thumbnail carousels, responsive breakpoints, and vertical scrolling.
Fix: Fumadocs Not Working — Pages Not Found, Search Not Indexing, or MDX Components Missing
How to fix Fumadocs documentation framework issues — Next.js App Router setup, content source configuration, sidebar generation, MDX components, search, OpenAPI integration, and custom themes.
Fix: gql.tada Not Working — Types Not Inferred, Schema Not Found, or IDE Not Showing Completions
How to fix gql.tada issues — schema introspection, type-safe GraphQL queries, fragment masking, urql and Apollo Client integration, IDE setup, and CI type checking.
Fix: GraphQL Yoga Not Working — Schema Errors, Resolvers Not Executing, or Subscriptions Failing
How to fix GraphQL Yoga issues — schema definition, resolver patterns, context and authentication, file uploads, subscriptions with SSE, error handling, and Next.js integration.
Fix: GSAP Not Working — Animations Not Playing, ScrollTrigger Not Firing, or React Cleanup Issues
How to fix GSAP animation issues — timeline and tween basics, ScrollTrigger setup, React useGSAP hook, cleanup and context, SplitText, stagger animations, and Next.js integration.
Fix: i18next Not Working — Translations Missing, Language Not Switching, or Namespace Errors
How to fix i18next issues — react-i18next setup, translation file loading, namespace configuration, language detection, interpolation, pluralization, and Next.js integration.
Fix: ky Not Working — Requests Failing, Hooks Not Firing, or Retry Not Working
How to fix ky HTTP client issues — instance creation, hooks (beforeRequest, afterResponse), retry configuration, timeout handling, JSON parsing, error handling, and migration from fetch or axios.
Fix: LangChain.js Not Working — Chain Not Executing, Retriever Returning Empty, or Memory Lost Between Calls
How to fix LangChain.js issues — model setup, prompt templates, RAG with vector stores, conversational memory, structured output, tool agents, and streaming with LangChain Expression Language.
Fix: Lingui Not Working — Messages Not Extracted, Translations Missing, or Macro Errors
How to fix Lingui.js i18n issues — setup with React, message extraction, macro compilation, ICU format, lazy loading catalogs, and Next.js integration.
Fix: Lottie Not Working — Animation Not Playing, File Not Loading, or React Component Blank
How to fix Lottie animation issues — lottie-react and lottie-web setup, JSON animation loading, playback control, interactivity, lazy loading, and performance optimization.
Fix: Mantine Not Working — Styles Not Loading, Theme Not Applying, or Components Broken After Upgrade
How to fix Mantine UI issues — MantineProvider setup, PostCSS configuration, theme customization, dark mode, form validation with useForm, and Next.js App Router integration.
Fix: Mapbox GL JS Not Working — Map Not Rendering, Markers Missing, or Access Token Invalid
How to fix Mapbox GL JS issues — access token setup, React integration with react-map-gl, markers and popups, custom layers, geocoding, directions, and Next.js configuration.
Fix: Monaco Editor Not Working — Editor Not Loading, TypeScript Errors, or Web Workers Failing
How to fix Monaco Editor issues — React integration with @monaco-editor/react, worker setup, TypeScript IntelliSense, custom themes, multi-file editing, and Next.js configuration.
Fix: next-safe-action Not Working — Action Not Executing, Validation Errors Missing, or Type Errors
How to fix next-safe-action issues — action client setup, Zod schema validation, useAction and useOptimisticAction hooks, middleware, error handling, and authorization patterns.
Fix: Nextra Not Working — Pages Not Rendering, Sidebar Missing, or MDX Components Broken
How to fix Nextra documentation site issues — Next.js integration, _meta.json sidebar configuration, custom MDX components, search setup, theme customization, and static export.
Fix: nuqs Not Working — URL State Not Syncing, Type Errors, or Server Component Issues
How to fix nuqs URL search params state management — useQueryState and useQueryStates setup, parsers, server-side access, shallow routing, history mode, and Next.js App Router integration.
Fix: Orval Not Working — Code Generation Failing, Types Not Matching API, or Hooks Not Updating
How to fix Orval API client generation issues — OpenAPI spec configuration, custom output targets, React Query and Axios integration, mock generation, type overrides, and CI/CD automation.
Fix: pdf-lib Not Working — PDF Not Generating, Fonts Not Embedding, or Pages Blank
How to fix pdf-lib issues — creating PDFs from scratch, modifying existing PDFs, embedding fonts and images, form filling, merging documents, and browser and Node.js usage.
Fix: Paraglide Not Working — Messages Not Loading, Compiler Errors, or Framework Integration Issues
How to fix Paraglide.js i18n issues — message compilation, type-safe translations, SvelteKit and Next.js integration, language switching, and message extraction from existing code.
Fix: Pothos Not Working — Types Not Resolving, Plugin Errors, or Prisma Integration Failing
How to fix Pothos GraphQL schema builder issues — type-safe schema definition, object and input types, Prisma plugin, relay connections, auth scope plugin, and schema printing.
Fix: PostHog Not Working — Events Not Tracking, Feature Flags Stale, or Session Replay Blank
How to fix PostHog analytics issues — JavaScript and Next.js setup, event capture, feature flags, A/B testing, session replay, user identification, and server-side tracking.
Fix: PowerSync Not Working — Offline Sync Failing, Queries Returning Stale Data, or Backend Connection Errors
How to fix PowerSync issues — SQLite local database, sync rules configuration, backend connector setup, watched queries, offline-first patterns, and React and React Native integration.
Fix: Prism React Renderer Not Working — No Syntax Colors, Wrong Language, or Custom Theme Not Applying
How to fix prism-react-renderer issues — Highlight component setup, language support, custom themes, line highlighting, copy button, and integration with MDX and documentation sites.
Fix: publint Not Working — Package Exports Invalid, Types Not Found, or Dual Package Errors
How to fix publint package validation issues — exports field configuration, dual ESM/CJS packaging, type resolution, main/module/types fields, files array, and common packaging mistakes.
Fix: Pusher Not Working — Events Not Received, Channel Auth Failing, or Connection Dropping
How to fix Pusher real-time issues — client and server setup, channel types, presence channels, authentication endpoints, event binding, connection management, and React integration.
Fix: React Aria Not Working — Components Not Rendering, ARIA Attributes Missing, or Styling Conflicts
How to fix React Aria and React Aria Components issues — hooks vs components API, styling with Tailwind CSS, custom components, collections pattern, forms, and accessibility compliance.
Fix: React PDF Not Working — PDF Not Rendering, Worker Error, or Pages Blank
How to fix react-pdf and @react-pdf/renderer issues — PDF viewer setup, worker configuration, page rendering, text selection, annotations, and generating PDFs in React.
Fix: React Three Fiber Not Working — Canvas Blank, Models Not Loading, or Performance Dropping
How to fix React Three Fiber (R3F) issues — Canvas setup, loading 3D models with useGLTF, lighting, camera controls, animations with useFrame, post-processing, and Next.js integration.
Fix: Scalar Not Working — API Docs Not Rendering, Try-It Not Sending Requests, or Theme Broken
How to fix Scalar API documentation issues — OpenAPI spec loading, interactive Try-It panel, authentication configuration, custom themes, CDN and React integration, and self-hosting.
Fix: Sentry Not Working — Errors Not Captured, Source Maps Missing, or Performance Traces Empty
How to fix Sentry issues — SDK initialization, source map uploads, error boundaries, performance monitoring, Next.js integration, release tracking, and alert configuration.
Fix: Sharp Not Working — Installation Failing, Image Not Processing, or Build Errors on Deploy
How to fix Sharp image processing issues — native binary installation, resize and convert operations, Next.js image optimization, Docker setup, serverless deployment, and common platform errors.
Fix: Shiki Not Working — No Syntax Highlighting, Wrong Theme, or Build Errors
How to fix Shiki syntax highlighter issues — basic setup, theme configuration, custom languages, transformer plugins, Next.js and Astro integration, and bundle size optimization.
Fix: Sonner Not Working — Toasts Not Showing, Styling Broken, or Server Component Errors
How to fix Sonner toast notification issues — Toaster setup, toast types, custom styling, promise toasts, action buttons, positioning, dark mode, and Next.js App Router integration.
Fix: Starlight Not Working — Pages Not Rendering, Sidebar Wrong, or Custom Components Broken
How to fix Astro Starlight documentation site issues — configuration, sidebar ordering, custom components, overrides, i18n, search, and content collections.
Fix: Stripe Integration Not Working — Checkout Failing, Webhooks Not Firing, or Subscriptions Not Updating
How to fix Stripe issues in Node.js and Next.js — Checkout Sessions, webhook signature verification, subscription lifecycle, customer portal, price management, and idempotent API calls.
Fix: Supertest Not Working — Requests Not Sending, Server Not Closing, or Assertions Failing
How to fix Supertest HTTP testing issues — Express and Fastify setup, async test patterns, authentication headers, file uploads, JSON body assertions, and Vitest/Jest integration.
Fix: Trigger.dev Not Working — Tasks Not Running, Runs Failing, or Dev Server Not Connecting
How to fix Trigger.dev issues — task definition and triggering, dev server setup, scheduled tasks with cron, concurrency and queues, retries, idempotency, and deployment to Trigger.dev Cloud.
Fix: ts-rest Not Working — Contract Types Not Matching, Client Requests Failing, or Server Validation Errors
How to fix ts-rest issues — contract definition, type-safe client and server setup, Zod validation, Next.js App Router integration, error handling, and OpenAPI generation.
Fix: tsup Not Working — Build Failing, Types Not Generated, or ESM/CJS Output Wrong
How to fix tsup bundler issues — entry points, dual ESM/CJS output, TypeScript declaration files, external dependencies, tree shaking, and package.json exports configuration.
Fix: unbuild Not Working — Build Output Empty, Stub Mode Failing, or Rollup Errors
How to fix unbuild issues — build configuration, stub mode for development, ESM and CJS output, TypeScript declarations, external dependencies, and monorepo workspace builds.
Fix: Vercel AI SDK Not Working — Streaming Not Rendering, useChat Stuck Loading, or Provider Errors
How to fix Vercel AI SDK issues — useChat and useCompletion hooks, streaming responses with streamText, provider configuration for OpenAI and Anthropic, tool calling, and Next.js integration.
Fix: View Transitions API Not Working — No Animation Between Pages, Cross-Document Transitions Failing, or Fallback Missing
How to fix View Transitions API issues — same-document transitions, cross-document MPA transitions, view-transition-name CSS, Next.js and Astro integration, custom animations, and browser support.
Fix: Auth.js (NextAuth) Not Working — Session Null, OAuth Callback Error, or CSRF Token Mismatch
How to fix Auth.js and NextAuth.js issues — OAuth provider setup, session handling in App Router and Pages Router, JWT vs database sessions, middleware protection, and credential provider configuration.
Fix: Capacitor Not Working — Build Failing, Plugins Not Loading, or Native Features Not Available
How to fix Capacitor issues — project setup with Ionic or standalone, native plugin access, iOS and Android build errors, live reload, deep links, push notifications, and migration from Cordova.
Fix: Cypress Not Working — Tests Timing Out, Elements Not Found, or cy.intercept Not Matching
How to fix Cypress issues — element selection strategies, async command chaining, cy.intercept for network stubbing, component testing, authentication handling, and flaky test debugging.
Fix: Effect (effect-ts) Not Working — Effect Not Running, Services Missing, or Type Errors
How to fix Effect issues — running effects with Effect.runPromise, Layer and service dependency injection, error channel types, Fiber concurrency, Schema validation, and common TypeScript errors.
Fix: Electron Not Working — Window Not Showing, IPC Not Communicating, or Build Failing
How to fix Electron issues — main and renderer process setup, IPC communication with contextBridge, preload scripts, auto-update, native module rebuilding, and packaging with electron-builder.
Fix: Inngest Not Working — Functions Not Triggering, Steps Failing, or Events Not Received
How to fix Inngest issues — function and event setup, step orchestration, retries and error handling, cron scheduling, concurrency control, fan-out patterns, and local development with the Dev Server.
Fix: jose JWT Not Working — Token Verification Failing, Invalid Signature, or Key Import Errors
How to fix jose JWT issues — signing and verifying tokens with HS256 and RS256, JWK and JWKS key handling, token expiration, claims validation, and edge runtime compatibility.
Fix: Liveblocks Not Working — Room Not Connecting, Presence Not Syncing, or Storage Mutations Lost
How to fix Liveblocks issues — room setup, real-time presence with useOthers, conflict-free storage with useMutation, Yjs integration, authentication, and React suspense patterns.
Fix: Million.js Not Working — Compiler Errors, Components Not Optimized, or React Compatibility Issues
How to fix Million.js issues — compiler setup with Vite and Next.js, block() optimization rules, component compatibility constraints, automatic mode, and debugging performance gains.
Fix: Neon Database Not Working — Connection Timeout, Branching Errors, or Serverless Driver Issues
How to fix Neon Postgres issues — connection string setup, serverless HTTP driver vs TCP, database branching, connection pooling, Drizzle and Prisma integration, and cold start optimization.
Fix: Nitro Not Working — Server Routes Not Found, Middleware Not Running, or Deploy Failing
How to fix Nitro server engine issues — route handlers, middleware, storage with unstorage, caching, WebSocket support, deployment presets for Cloudflare Workers, Vercel, and Node.js.
Fix: Panda CSS Not Working — Styles Not Applying, Tokens Not Resolving, or Build Errors
How to fix Panda CSS issues — PostCSS setup, panda.config.ts token system, recipe and pattern definitions, conditional styles, responsive design, and integration with Next.js and Vite.
Fix: Payload CMS Not Working — Collections Not Loading, Auth Failing, or Admin Panel Blank
How to fix Payload CMS issues — collection and global config, access control, hooks, custom fields, REST and GraphQL APIs, Next.js integration, and database adapter setup.
Fix: Qwik Not Working — Components Not Rendering, useSignal Not Reactive, or Serialization Errors
How to fix Qwik issues — component$ boundaries, useSignal and useStore reactivity, serialization with dollar signs, useTask$ and useVisibleTask$, Qwik City routing, and integration with React components.
Fix: Radix UI Not Working — Popover Not Opening, Dialog Closing Immediately, or Styling Breaking
How to fix Radix UI issues — Popover and Dialog setup, controlled vs uncontrolled state, portal rendering, animation with CSS or Framer Motion, accessibility traps, and Tailwind CSS integration.
Fix: React Email and Resend Not Working — Emails Not Sending, Templates Not Rendering, or Styling Broken
How to fix React Email and Resend issues — email template components, inline styles, Resend API integration, preview server, attachments, and email client compatibility.
Fix: Rspack Not Working — Build Failing, Loaders Not Applying, or Dev Server Not Starting
How to fix Rspack issues — configuration migration from webpack, loader compatibility, CSS extraction, module federation, React Fast Refresh, and build performance tuning.
Fix: SST Not Working — Deploy Failing, Bindings Not Linking, or Lambda Functions Timing Out
How to fix SST (Serverless Stack) issues — resource configuration with sst.config.ts, linking resources to functions, local dev with sst dev, database and storage setup, and deployment troubleshooting.
Fix: Svelte 5 Runes Not Working — $state Not Reactive, $derived Not Updating, or $effect Running Twice
How to fix Svelte 5 Runes issues — $state and $state.raw reactivity, $derived computations, $effect lifecycle, $props and $bindable, migration from Svelte 4 stores, and component patterns.
Fix: TanStack Router Not Working — Routes Not Matching, Loader Not Running, or Type Errors
How to fix TanStack Router issues — file-based routing setup, route tree generation, loader and search params, authenticated routes, type-safe navigation, and code splitting.
Fix: Turso Not Working — Connection Refused, Queries Returning Empty, or Embedded Replicas Not Syncing
How to fix Turso database issues — libsql client setup, connection URLs and auth tokens, embedded replicas for local-first apps, schema migrations, Drizzle ORM integration, and edge deployment.
Fix: UnoCSS Not Working — Classes Not Generating, Presets Missing, or Attributify Mode Broken
How to fix UnoCSS issues — Vite plugin setup, preset configuration, attributify mode, icons preset, shortcuts, custom rules, and integration with Next.js, Nuxt, and Astro.
Fix: Upstash Not Working — Redis Commands Failing, Rate Limiter Not Blocking, or QStash Messages Lost
How to fix Upstash issues — Redis REST client setup, rate limiting with @upstash/ratelimit, QStash message queues, Kafka topics, Vector search, and edge runtime integration.
Fix: Vanilla Extract Not Working — Styles Not Applied, TypeScript Errors, or Build Failing
How to fix Vanilla Extract issues — .css.ts file setup, style and recipe APIs, sprinkles for utility classes, theme tokens, dynamic styles, and integration with Next.js, Vite, and Remix.
Fix: Wrangler Not Working — Deploy Failing, Bindings Not Found, or D1 Queries Returning Empty
How to fix Wrangler and Cloudflare Workers issues — wrangler.toml configuration, KV and D1 bindings, R2 storage, environment variables, local dev with Miniflare, and deployment troubleshooting.
Fix: Biome Not Working — Rules Not Applied, ESLint Config Not Migrated, or VSCode Extension Ignored
How to fix Biome linter/formatter issues — biome.json configuration, migrating from ESLint and Prettier, VSCode extension setup, CI integration, and rule override syntax.
Fix: Convex Not Working — Query Not Updating, Mutation Throwing Validation Error, or Action Timing Out
How to fix Convex backend issues — query/mutation/action patterns, schema validation, real-time reactivity, file storage, auth integration, and common TypeScript type errors.
Fix: date-fns Not Working — Wrong Timezone Output, Invalid Date, or Locale Not Applied
How to fix date-fns issues — timezone handling with date-fns-tz, parseISO vs new Date, locale import and configuration, DST edge cases, v3 ESM migration, and common format pattern mistakes.
Fix: dnd-kit Not Working — Drag Not Starting, Sort Order Not Updating, or Items Jumping on Drop
How to fix dnd-kit issues — DndContext setup, sensors configuration, useSortable with SortableContext, drag overlays, collision detection algorithms, and accessible drag and drop.
Fix: Docker Secrets Not Working — BuildKit --secret Not Mounting, Compose Secrets Undefined, or Secret Leaking into Image
How to fix Docker secrets — BuildKit secret mounts in Dockerfile, docker-compose secrets config, runtime vs build-time secrets, environment variable alternatives, and verifying secrets don't leak into image layers.
Fix: esbuild Not Working — Plugin Errors, CSS Not Processed, or Output Missing After Build
How to fix esbuild issues — entry points, plugin API, JSX configuration, CSS modules, watch mode, metafile analysis, external packages, and common migration problems from webpack.
Fix: Expo Not Working — Build Failing, Native Module Not Found, or EAS Build Error
How to fix Expo issues — Expo Go vs development builds, native module installation with expo-modules-core, EAS Build configuration, bare workflow setup, and common SDK upgrade problems.
Fix: Framer Motion Not Working — Animation Not Playing, Exit Animation Skipped, or Layout Shift on Mount
How to fix Framer Motion issues — variants, AnimatePresence for exit animations, layout animations, useMotionValue, server component errors, and performance optimization.
Fix: Git Hooks Not Running — Husky Not Working, pre-commit Skipped, or lint-staged Failing
How to fix Git hooks not executing — Husky v9 setup, hook file permissions, lint-staged configuration, pre-commit Python tool, lefthook, and bypassing hooks in CI.
Fix: Hono Not Working — Route Not Matching, Middleware Skipped, or RPC Client Type Mismatch
How to fix Hono framework issues — routing order, middleware chaining, Hono RPC type inference, Cloudflare Workers bindings, validator integration, and runtime compatibility.
Fix: HTMX Not Working — hx-get Request Not Firing, Swap Not Updating DOM, or Response Ignored
How to fix HTMX issues — attribute syntax, target and swap strategies, out-of-band swaps, event handling, CSP configuration, response headers, and debugging HTMX requests.
Fix: Jotai Not Working — Atom Not Updating, Derived Atom Out of Sync, or atomWithStorage Hydration Error
How to fix Jotai state management issues — atom scope, derived atoms, async atoms with Suspense, atomWithStorage SSR, useAtomValue vs useSetAtom, and debugging stale state.
Fix: Kysely Not Working — Type Errors on Queries, Migration Failing, or Generated Types Not Matching Schema
How to fix Kysely query builder issues — database interface definition, dialect setup, type-safe joins and subqueries, migration runner, kysely-codegen for generated types, and common TypeScript errors.
Fix: Lucia Auth Not Working — Session Not Created, Middleware Rejecting Valid Sessions, or OAuth Callback Failing
How to fix Lucia auth issues — adapter setup, session validation in middleware, cookie configuration, OAuth provider integration, Next.js App Router setup, and Lucia v3 migration.
Fix: MDX Not Working — Components Not Rendering, Imports Failing, or Frontmatter Not Parsed
How to fix MDX issues — Next.js App Router setup with @next/mdx and next-mdx-remote, custom component mapping, frontmatter parsing with gray-matter, remark and rehype plugins, and TypeScript configuration.
Fix: MSW (Mock Service Worker) Not Working — Handlers Not Intercepting, Browser Not Mocking, or v2 Migration Errors
How to fix Mock Service Worker issues — browser vs Node setup, handler registration, worker start timing, passthrough requests, and common MSW v2 API changes from v1.
Fix: next-intl Not Working — Translations Missing, Locale Not Detected, or Middleware Redirect Loop
How to fix next-intl issues — App Router setup with middleware, useTranslations in server and client components, locale detection, pluralization, number and date formatting, and routing configuration.
Fix: Nuxt Not Working — useFetch Returns Undefined, Server Route 404, or Hydration Mismatch
How to fix Nuxt 3 issues — useFetch vs $fetch, server routes in server/api, composable SSR rules, useAsyncData, hydration errors, and Nitro configuration problems.
Fix: Playwright Not Working — Test Timeout, Selector Not Found, or CI Headless Fails
How to fix Playwright test issues — locator strategies, auto-waiting, network mocking, flaky tests in CI, trace viewer debugging, and common headless browser setup problems.
Fix: Python Packaging Not Working — Build Fails, Package Not Found After Install, or PyPI Upload Errors
How to fix Python packaging issues — pyproject.toml setup, build backends (setuptools/hatchling/flit), wheel vs sdist, editable installs, package discovery, and twine upload to PyPI.
Fix: React Native Reanimated Not Working — Worklet Error, useAnimatedStyle Not Updating, or Gesture Not Responding
How to fix React Native Reanimated issues — worklet rules, shared values, useAnimatedStyle, Gesture Handler setup, web support, Babel plugin configuration, and Reanimated 3 migration.
Fix: Recharts Not Working — Chart Not Rendering, Tooltip Missing, or ResponsiveContainer Showing Zero Height
How to fix Recharts issues — ResponsiveContainer setup, data format for each chart type, custom tooltips, axis configuration, legends, animations, and TypeScript types.
Fix: Remix Not Working — Loader Returns Undefined, Action Not Triggered, or Nested Route Data Missing
How to fix Remix issues — loader and action setup, nested route outlet, useLoaderData typing, error boundaries, defer with Await, and common React Router v7 migration problems.
Fix: RxJS Not Working — Observable Not Emitting, Memory Leak from Unsubscribed Stream, or Operator Behaving Unexpectedly
How to fix RxJS issues — subscription management, switchMap vs mergeMap vs concatMap, error handling with catchError, Subject types, cold vs hot observables, and Angular async pipe.
Fix: shadcn/ui Not Working — Components Not Rendering, Styles Missing, or Dark Mode Broken
How to fix shadcn/ui issues — Tailwind CSS v4 vs v3 configuration, CSS variables, dark mode setup, component installation, cn() utility, and common errors after adding components.
Fix: SolidJS Not Working — Signal Not Updating, Effect Running Twice, or createResource Data Undefined
How to fix SolidJS reactivity issues — signal access inside JSX, effect dependencies, createResource with loading states, Show and For components, store mutations, and common mistakes coming from React.
Fix: Storybook Not Working — Addon Conflicts, Component Not Rendering, or Build Fails After Upgrade
How to fix Storybook issues — CSF3 story format, addon configuration, webpack vs Vite builder, decorator setup, args not updating component, and Storybook 8 migration problems.
Fix: styled-components Not Working — Styles Not Applying, SSR Flash of Unstyled Content, or Theme Not Available
How to fix styled-components issues — ThemeProvider setup, Next.js SSR with ServerStyleSheet, shouldForwardProp, attrs, TypeScript theme typing, and styled-components v6 migration.
Fix: Supabase Not Working — RLS Policy Blocking Queries, Realtime Not Receiving Updates, or Auth Session Lost
How to fix Supabase issues — Row Level Security policies, realtime subscriptions, storage permissions, auth session with Next.js, edge functions, and common client configuration mistakes.
Fix: SvelteKit Not Working — load Function Errors, Form Actions Failing, or SSR Data Not Available
How to fix SvelteKit issues — load function data flow, +page.server.ts vs +page.ts, form actions with use:enhance, hooks.server.ts, SSR vs CSR mode, and common routing mistakes.
Fix: Swift async/await Not Working — Task Not Running, Actor Isolation Error, or MainActor Crash
How to fix Swift concurrency issues — async/await in non-async context, Task creation, actor isolation violations, MainActor UI updates, structured concurrency, and Sendable errors.
Fix: TanStack Query Not Working — Data Not Fetching, Cache Not Updating, or Mutation Not Triggering Re-render
How to fix TanStack Query (React Query v5) issues — query keys, stale time, enabled flag, mutation callbacks, optimistic updates, QueryClient setup, and SSR with prefetchQuery.
Fix: TanStack Table Not Working — Sorting Not Triggering, Filters Ignored, or Pagination Showing Wrong Data
How to fix TanStack Table (React Table v8) issues — column definitions, server-side sorting and filtering, row selection, virtual rows with TanStack Virtual, and v7 to v8 migration errors.
Fix: Tauri Not Working — Command Not Found, IPC Error, File System Permission Denied, or Build Fails
How to fix Tauri app issues — Rust command registration, invoke IPC, tauri.conf.json permissions, fs scope, window management, and common build errors on Windows/macOS/Linux.
Fix: Tiptap Not Working — Editor Not Rendering, Extensions Missing, or Content Not Saving
How to fix Tiptap editor issues — useEditor setup in React, StarterKit configuration, custom nodes and marks, SSR with Next.js, collaborative editing, and content serialization.
Fix: Turborepo Not Working — Cache Never Hits, Pipeline Not Running, or Workspace Task Fails
How to fix Turborepo issues — turbo.json pipeline configuration, cache keys, remote caching setup, workspace filtering, and common monorepo task ordering mistakes.
Fix: Valtio Not Working — Component Not Re-rendering, Snapshot Stale, or Proxy Mutation Not Tracked
How to fix Valtio state management issues — proxy vs snapshot, useSnapshot for React, subscribe for side effects, derived state with computed, async actions, and Valtio with React Server Components.
Fix: WebAssembly (WASM) Not Working — Module Fails to Load, Memory Error, or JS Interop Broken
How to fix WebAssembly issues — instantiateStreaming vs instantiate, CORS for WASM files, linear memory limits, wasm-bindgen JS interop, imports/exports mismatch, and WASM in bundlers.
Fix: XState Not Working — Machine Not Transitioning, Guards Not Running, or Actor Not Sending Events
How to fix XState v5 issues — state machine definition, guards and actions typed correctly, useMachine hook, createActor, context updates, child actors, and common v4 to v5 migration errors.
Fix: Zustand Not Working — Component Not Re-rendering, State Reset on Refresh, or Selector Causing Infinite Loop
How to fix Zustand state management issues — selector optimization, persist middleware, shallow comparison, devtools setup, slice pattern for large stores, and common subscription mistakes.
Fix: Angular Pipe Not Working — Custom Pipe Not Transforming or async Pipe Not Rendering
How to fix Angular pipe issues — declaring pipes in modules, standalone pipe imports, pure vs impure pipes, async pipe with observables, pipe chaining, and custom pipe debugging.
Fix: AWS Lambda Layer Not Working — Module Not Found or Layer Not Applied
How to fix AWS Lambda Layer issues — directory structure, runtime compatibility, layer ARN configuration, dependency conflicts, size limits, and container image alternatives.
Fix: AWS SQS Not Working — Messages Not Received, Duplicate Processing, or DLQ Filling Up
How to fix AWS SQS issues — visibility timeout, message not delivered, duplicate messages, Dead Letter Queue configuration, FIFO queue ordering, and Lambda trigger problems.
Fix: Bun Not Working — Node.js Module Incompatible, Native Addon Fails, or bun test Errors
How to fix Bun runtime issues — Node.js API compatibility, native addons (node-gyp), Bun.serve vs Node http, bun test differences from Jest, and common package incompatibilities.
Fix: Celery Beat Not Working — Scheduled Tasks Not Running or Beat Not Starting
How to fix Celery Beat issues — beat scheduler not starting, tasks not executing on schedule, timezone configuration, database scheduler, and running beat with workers.
Fix: CSS Scroll Behavior Not Working — smooth scroll, scroll-snap, or scroll-margin Ignored
How to fix CSS scroll issues — scroll-behavior: smooth not working, scroll-snap alignment problems, overflow container conflicts, scroll-margin for fixed headers, and browser compatibility.
Fix: Docker Compose Healthcheck Not Working — depends_on Not Waiting or Always Unhealthy
How to fix Docker Compose healthcheck issues — depends_on condition service_healthy, healthcheck command syntax, start_period, custom health scripts, and debugging unhealthy containers.
Fix: Docker Multi-Platform Build Not Working — buildx Fails, Wrong Architecture, or QEMU Error
How to fix Docker multi-platform build issues — buildx setup, QEMU registration, --platform flag usage, architecture-specific dependencies, and pushing multi-arch manifests to a registry.
Fix: Drizzle ORM Not Working — Schema Out of Sync, Relation Query Fails, or Migration Error
How to fix Drizzle ORM issues — schema definition, drizzle-kit push vs migrate, relation queries with, transactions, type inference, and common PostgreSQL/MySQL configuration problems.
Fix: ESLint Config Not Working — Rules Ignored, Flat Config Errors, or Plugin Not Found
How to fix ESLint configuration issues — flat config vs legacy config, extends conflicts, parser options, plugin resolution, per-directory overrides, and migrating to ESLint 9.
Fix: Express Middleware Not Working — Order Wrong, Errors Not Caught, or async Errors Silently Dropped
How to fix Express middleware issues — middleware execution order, error-handling middleware signature, async error propagation with next(err), and common middleware misconfigurations.
Fix: GitHub Actions Artifacts Not Working — Upload Fails, Download Empty, or Artifact Not Found
How to fix GitHub Actions artifact issues — upload-artifact path patterns, download-artifact across jobs, retention days, artifact name conflicts, and the v3 to v4 migration.
Fix: GitHub Actions Reusable Workflow Not Working — Inputs Not Passed or Secrets Not Available
How to fix GitHub Actions reusable workflow issues — workflow_call trigger, passing inputs and secrets, output variables, caller vs called permissions, and common errors.
Fix: GitHub Actions Job Timeout — Workflow Cancelled or Stuck After 6 Hours
How to fix GitHub Actions timeout issues — job-level and step-level timeouts, stuck processes, self-hosted runner timeouts, debugging hanging jobs, and timeout best practices.
Fix: Go Test Not Working, Tests Not Running, Failing Unexpectedly, or Coverage Not Collected
How to fix Go testing issues, test function naming, table-driven tests, t.Run subtests, httptest, testify assertions, and common go test flag errors.
Fix: gRPC Error Not Working — Status Codes, Connection Failed, or Deadline Exceeded
How to fix gRPC errors — UNAVAILABLE connection errors, DEADLINE_EXCEEDED, UNIMPLEMENTED, TLS setup, interceptors for error handling, and status code mapping.
Fix: IndexedDB Not Working — Transaction Inactive, Upgrade Blocked, or Store Not Found
How to fix IndexedDB issues — transaction lifecycle, version upgrades, blocked events, cursor iteration, IDBKeyRange queries, and using idb wrapper library to avoid callback hell.
Fix: Java Record Not Working — Compact Constructor Error, Serialization Fails, or Cannot Extend
How to fix Java record issues — compact constructor validation, custom accessor methods, Jackson serialization, inheritance restrictions, and when to use records vs regular classes.
Fix: Jest Setup File Not Working — setupFilesAfterFramework Not Running or Globals Not Applied
How to fix Jest setup file issues — setupFilesAfterFramework vs setupFiles, global mocks not applying, @testing-library/jest-dom matchers, module mocking in setup, and TypeScript setup files.
Fix: Kotlin Flow Not Working — Not Collecting, StateFlow Not Updating, or Flow Cancelled Unexpectedly
How to fix Kotlin Flow issues — cold vs hot flows, collectLatest vs collect, StateFlow and SharedFlow setup, lifecycle-aware collection in Android, and common Flow cancellation problems.
Fix: Kotlin Sealed Class Not Working — when Expression Not Exhaustive or Subclass Not Found
How to fix Kotlin sealed class issues — when exhaustiveness, sealed interface vs class, subclass visibility, Result pattern, and sealed classes across modules.
Fix: MySQL Replication Not Working — Replica Lag, Stopped Replication, or GTID Errors
How to fix MySQL replication issues — SHOW REPLICA STATUS errors, relay log corruption, GTID configuration, replication lag, skipping errors, and replica promotion.
Fix: NextAuth.js Not Working — Session Null, Callback Errors, or OAuth Redirect Issues
How to fix NextAuth.js (Auth.js) issues — session undefined in server components, OAuth callback URL mismatch, JWT vs database sessions, middleware protection, and credentials provider.
Fix: OpenTelemetry Not Working — Traces Not Appearing, Spans Missing, or Exporter Connection Refused
How to fix OpenTelemetry issues — SDK initialization order, auto-instrumentation setup, OTLP exporter configuration, context propagation, and missing spans in Node.js, Python, and Java.
Fix: Pinia Store Not Working — State Not Reactive, Actions Not Updating, or Store Not Found
How to fix Pinia store issues — state reactivity with storeToRefs, getters not updating, actions async patterns, store outside components, SSR hydration, and testing Pinia stores.
Fix: PostgreSQL JSONB Query Not Working — Operator Errors, Wrong Results, or Slow Queries
How to fix PostgreSQL JSONB query issues — -> vs ->> operators, @> containment, GIN indexes, type casting, array queries, and indexing strategies for JSONB columns.
Fix: PostgreSQL Row Level Security Not Working — Policy Not Applied, All Rows Visible, or Permission Denied
How to fix PostgreSQL Row Level Security (RLS) issues — enabling RLS, policy expressions, BYPASSRLS role, SET ROLE, current_user vs session_user, and Supabase auth.uid() patterns.
Fix: Python contextmanager Not Working — GeneratorExit, Missing yield, or Cleanup Not Running
How to fix Python context manager issues — @contextmanager generator, __enter__ and __exit__, exception handling inside with blocks, async context managers, and common pitfalls.
Fix: Python Protocol Not Working — Type Checker Rejects Compatible Class, runtime_checkable Fails, or Protocol Not Recognized
How to fix Python Protocol class issues — structural subtyping vs nominal typing, runtime_checkable, Protocol inheritance, TypeVar constraints, and common mypy/pyright errors with Protocol.
Fix: Python subprocess Not Working — Output Empty, Command Not Found, or Permission Denied
How to fix Python subprocess issues — capturing stdout/stderr, shell=True risks, Popen vs run, timeout handling, and common subprocess errors explained.
Fix: React Hook Form Not Working — register Not Applying, Validation Not Triggering, or Controller Issues
How to fix React Hook Form issues — register spread syntax, Controller for UI libraries, validation modes, watch vs getValues, nested fields, and form submission errors.
Fix: React useTransition Not Working — UI Still Freezes, isPending Never True, or Transition Not Deferred
How to fix React useTransition and startTransition issues — what counts as a transition, Suspense integration, concurrent rendering requirements, and common mistakes that prevent transitions from deferring.
Fix: Redis Cluster Not Working — MOVED, CROSSSLOT, or Connection Errors
How to fix Redis Cluster errors — MOVED redirects, CROSSSLOT multi-key operations, cluster-aware client setup, hash tags for key grouping, and failover handling.
Fix: Rust Error Handling Not Working — ? Operator, Custom Error Types, and thiserror/anyhow
How to fix Rust error handling issues — the ? operator, From trait for error conversion, thiserror for custom errors, anyhow for applications, and Box<dyn Error> pitfalls.
Fix: Spring Boot Test Not Working — ApplicationContext Fails to Load, MockMvc Returns 404, or @MockBean Not Injected
How to fix Spring Boot test issues — @SpringBootTest vs test slices, MockMvc setup, @MockBean vs @Mock, test context caching, and common test configuration mistakes.
Fix: Spring Boot @Cacheable Not Working — Cache Miss Every Time or Stale Data
How to fix Spring Boot @Cacheable issues — @EnableCaching missing, self-invocation bypass, key generation, TTL configuration, cache eviction, and Caffeine vs Redis setup.
Fix: Terraform Import Error — Resource Not Importable or State Conflict
How to fix Terraform import errors — terraform import syntax, import blocks (Terraform 1.5+), state conflicts, provider-specific import IDs, and importing existing infrastructure.
Fix: tRPC Not Working — Type Inference Lost, Procedure Not Found, or Context Not Available
How to fix tRPC issues — router setup, type inference across packages, context injection, middleware, error handling, and common tRPC v10/v11 configuration mistakes.
Fix: TypeScript Conditional Types Not Working — infer Not Extracting, Distributive Behavior Unexpected, or Type Resolves to never
How to fix TypeScript conditional type issues — infer keyword usage, distributive conditional types, deferred evaluation, naked type parameters, and common conditional type patterns.
Fix: TypeScript Discriminated Union Error — Property Does Not Exist or Narrowing Not Working
How to fix TypeScript discriminated union errors — type guards, exhaustive checks, narrowing with in operator, never type, and common patterns for tagged unions.
Fix: TypeScript Template Literal Type Error — Type Not Assignable or Inference Fails
How to fix TypeScript template literal type errors — string combination types, conditional inference, Extract and mapped types with template literals, and common pitfalls.
Fix: Vue Slot Not Working — Named Slots Not Rendering or Scoped Slot Data Not Accessible
How to fix Vue 3 slot issues — v-slot syntax, named slots, scoped slots passing data, default slot content, fallback content, and dynamic slot names.
Fix: Vue Router Params Not Updating — Component Not Re-rendering or beforeRouteUpdate Not Firing
How to fix Vue Router params not updating when navigating between same-route paths — watch $route, beforeRouteUpdate, onBeforeRouteUpdate, and component reuse behavior explained.
Fix: Web Worker Not Working — postMessage Ignored, Cannot Import Module, or Worker Crashes Silently
How to fix Web Worker issues — postMessage data cloning, module workers, error handling, SharedArrayBuffer setup, Comlink, and common reasons workers silently fail.
Fix: Zod Validation Not Working — safeParse Returns Wrong Error, transform Breaks Type, or discriminatedUnion Fails
How to fix Zod schema validation issues — parse vs safeParse, transform and preprocess, refine for cross-field validation, discriminatedUnion, error formatting, and common schema mistakes.
Fix: CSS Grid Layout Not Working — Items Not Placing or Spanning Correctly
How to fix CSS Grid issues — implicit vs explicit grid, grid-template-areas, auto-placement, subgrid, alignment, and common mistakes with grid-column and grid-row.
Fix: docker-compose.override.yml Not Working — Override File Ignored or Not Merged
How to fix docker-compose.override.yml not being applied — file naming, merge behavior, explicit file flags, environment-specific configs, and common override pitfalls.
Fix: FastAPI BackgroundTasks Not Working — Task Not Running or Dependency Errors
How to fix FastAPI BackgroundTasks — task not executing, dependency injection in tasks, error handling, Celery for heavy tasks, and lifespan-managed background workers.
Fix: Go Generics Type Constraint Error, Does Not Implement or Cannot Use as Type
How to fix Go generics errors, type constraints, interface vs constraint, comparable, union types, type inference failures, and common generic function pitfalls.
Fix: Kubernetes HPA Not Scaling — HorizontalPodAutoscaler Shows Unknown or Doesn't Scale
How to fix Kubernetes HorizontalPodAutoscaler issues — metrics-server not installed, CPU requests not set, unknown metrics, scale-down delay, custom metrics, and KEDA.
Fix: MongoDB Aggregation Pipeline Not Working — Wrong Results or Empty Array
How to fix MongoDB aggregation pipeline issues — $lookup field matching, $unwind on missing fields, $match placement, $group _id, type mismatches, and pipeline debugging.
Fix: NestJS Swagger UI Not Showing — /api-docs Returns 404 or Blank Page
How to fix NestJS Swagger UI not displaying — SwaggerModule setup, DocumentBuilder, decorators not appearing, guards blocking the docs route, and Fastify vs Express differences.
Fix: Next.js Server Action Not Working — Action Not Called or Returns Error
How to fix Next.js Server Actions — use server directive, form binding, revalidation, error handling, middleware conflicts, and client component limitations.
Fix: Node.js Stream Error — Pipe Not Working, Backpressure, or Premature Close
How to fix Node.js stream issues — pipe and pipeline errors, backpressure handling, Transform streams, async iteration, error propagation, and common stream anti-patterns.
Fix: Prisma Enum Not Working — Invalid Enum Value or Enum Not Recognized
How to fix Prisma enum errors — schema definition, database sync, TypeScript enum type mismatch, filtering by enum, and migrating existing enum values.
Fix: Python pathlib Not Working — Path Object Errors, Joins, and Common Pitfalls
How to fix Python pathlib issues — TypeError with string concatenation, path joining, glob patterns, reading files, cross-platform paths, and migrating from os.path.
Fix: React Testing Library Not Finding Element — Unable to Find Role or Text
How to fix React Testing Library query failures — getByRole vs getByText, async queries, accessible names, waitFor patterns, custom queries, and common selector mistakes.
Fix: Spring Data JPA Query Not Working — @Query, Derived Methods, and N+1 Problems
How to fix Spring Data JPA query issues — JPQL vs native SQL, derived method naming, @Modifying for updates, pagination, projections, and LazyInitializationException.
Fix: Vite Proxy Not Working — API Requests Not Forwarded or 404/502 Errors
How to fix Vite dev server proxy issues — proxy configuration in vite.config.ts, path rewriting, WebSocket proxying, HTTPS targets, and common misconfigurations.
Fix: Vue Teleport Not Rendering — Content Not Appearing at Target Element
How to fix Vue Teleport not working — target element not found, SSR with Teleport, disabled prop, multiple Teleports to the same target, and timing issues.
Fix: Angular HTTP Interceptor Not Working — Requests Not Intercepted
How to fix Angular HTTP interceptors not triggering — provideHttpClient setup, functional interceptors, order of interceptors, excluding specific URLs, and error handling.
Fix: Angular Signals Not Updating — computed() and effect() Not Triggering
How to fix Angular Signals not updating — signal mutations, computed dependency tracking, effect() cleanup, toSignal() with Observables, and migrating from zone-based change detection.
Fix: Angular Standalone Component Error — Component is Not a Known Element
How to fix Angular standalone component errors — imports array, NgModule migration, RouterModule vs RouterLink, CommonModule replacement, and mixing standalone with module-based components.
Fix: AWS Lambda Environment Variable Not Set — undefined or Missing at Runtime
How to fix AWS Lambda environment variables not available — Lambda console config, CDK/SAM/Terraform setup, secrets from SSM Parameter Store, encrypted variables, and local testing.
Fix: AWS S3 CORS Error — Access to Fetch Blocked by CORS Policy
How to fix AWS S3 CORS errors — S3 bucket CORS configuration, pre-signed URL CORS, CloudFront CORS headers, OPTIONS preflight requests, and presigned POST uploads.
Fix: Tailwind CSS Classes Not Applying — Styles Missing in Production or Development
How to fix Tailwind CSS not applying styles — content config paths, JIT mode, dynamic class names, PostCSS setup, CDN vs build tool, and purging issues.
Fix: Docker Build ARG Not Available — ENV Variables Missing at Runtime
How to fix Docker ARG and ENV variable issues — build-time vs runtime scope, ARG before FROM, multi-stage build variable passing, secret handling, and .env file patterns.
Fix: Docker HEALTHCHECK Failing — Container Marked Unhealthy Despite Running
How to fix Docker HEALTHCHECK failures — command syntax, curl vs wget availability, start period, interval tuning, health check in docker-compose, and debugging unhealthy containers.
Fix: Express Rate Limit Not Working — express-rate-limit Requests Not Throttled
How to fix Express rate limiting not working — middleware order, trust proxy for reverse proxies, IP detection, store configuration, custom key generation, and bypassing issues.
Fix: GitHub Actions Secret Not Available — Environment Variable Empty in Workflow
How to fix GitHub Actions secrets that appear empty or undefined in workflows — secret scope, fork PR restrictions, environment protection rules, secret names, and OIDC alternatives.
Fix: Go Error Handling Not Working — errors.Is, errors.As, and Wrapping
How to fix Go error handling — errors.Is vs ==, errors.As for type extraction, fmt.Errorf %w for wrapping, sentinel errors, custom error types, and stack traces.
Fix: Go Panic Not Recovered, panic/recover Patterns and Common Pitfalls
How to handle Go panics correctly, recover() placement, goroutine panics, HTTP middleware recovery, defer ordering, distinguishing panics from errors, and when not to use recover.
Fix: GraphQL Error Handling Not Working — Errors Not Returned or Always 200 OK
How to fix GraphQL error handling — error extensions, partial data with errors, Apollo formatError, custom error classes, client-side error detection, and network vs GraphQL errors.
Fix: GraphQL Subscription Not Updating — WebSocket Connection Not Receiving Events
How to fix GraphQL subscriptions not receiving updates — WebSocket setup, subscription protocol, Apollo Client config, server-side pub/sub, authentication over WebSocket, and reconnection.
Fix: Jest Async Test Timeout — Exceeded 5000ms or Test Never Resolves
How to fix Jest async test timeouts — missing await, unresolved Promises, done callback misuse, global timeout configuration, fake timers, and async setup/teardown issues.
Fix: Jest Coverage Not Collected — Files Missing from Coverage Report
How to fix Jest coverage not collecting all files — collectCoverageFrom config, coverage thresholds, Istanbul ignore comments, ts-jest setup, and Babel transform issues.
Fix: Kotlin Coroutine Not Executing — launch{} or async{} Blocks Not Running
How to fix Kotlin coroutines not executing — CoroutineScope setup, dispatcher selection, structured concurrency, cancellation handling, blocking vs suspending calls, and exception propagation.
Fix: Kotlin Coroutine Scope Cancelled — JobCancellationException or Coroutine Not Running
How to fix Kotlin coroutine cancellation issues — scope lifecycle, SupervisorJob, CancellationException handling, structured concurrency, viewModelScope, and cooperative cancellation.
Fix: Laravel Queue Job Not Processing — Jobs Stuck in Queue
How to fix Laravel queue jobs not running — queue worker not started, wrong connection config, failed jobs, job timeouts, horizon setup, and database vs Redis queue differences.
Fix: MongoDB Schema Validation Error — Document Failed Validation
How to fix MongoDB schema validation errors — $jsonSchema rules, required fields, type mismatches, enum constraints, bypassing validation for migrations, and Mongoose schema conflicts.
Fix: MySQL Full-Text Search Not Working — MATCH AGAINST Returns No Results
How to fix MySQL full-text search issues — FULLTEXT index creation, minimum word length, stopwords, boolean mode vs natural language mode, InnoDB vs MyISAM, and LIKE fallback.
Fix: NestJS Nest can't resolve dependencies — Provider Not Found Error
How to fix NestJS dependency injection errors — module imports, provider exports, circular dependencies, dynamic modules, and the most common 'can't resolve dependencies' patterns.
Fix: NestJS ValidationPipe Not Working — class-validator Decorators Ignored
How to fix NestJS ValidationPipe not validating requests — global pipe setup, class-transformer, whitelist and transform options, custom validators, and DTO inheritance issues.
Fix: Next.js Font Not Loading — Custom Fonts Not Applying or Flashing
How to fix Next.js font loading issues — next/font/google setup, CSS variable approach, local fonts, font-display settings, FOUT flash, and Tailwind CSS font integration.
Fix: nginx Upstream Load Balancing Not Working — All Traffic Hitting One Server
How to fix nginx load balancing issues — upstream block configuration, health checks, least_conn vs round-robin, sticky sessions, upstream timeouts, and SSL termination.
Fix: PHP Session Not Working — $_SESSION Variables Lost Between Requests
How to fix PHP session variables that don't persist between requests — session_start() placement, cookie settings, session storage, shared hosting, and session fixation security.
Fix: PostgreSQL Index Not Being Used — Query Planner Ignores Index
How to fix PostgreSQL indexes not being used — EXPLAIN ANALYZE output, function on indexed column, type mismatches, statistics staleness, partial indexes, and query planner costs.
Fix: Prisma Connection Pool Exhausted — Can't Acquire Connection from Pool
How to fix Prisma connection pool errors — pool size configuration, connection leaks, serverless deployments, singleton pattern, query timeout, and pgBouncer integration.
Fix: Python asyncio.gather Not Handling Errors — Exceptions Swallowed or All Tasks Cancelled
How to fix asyncio.gather error handling — return_exceptions parameter, partial failures, task cancellation propagation, TaskGroup alternatives, and exception isolation patterns.
Fix: Python Decorator Not Working — Function Signature Lost or Decorator Not Applied
How to fix Python decorator issues — functools.wraps, decorator factories with arguments, class decorators, stacking order, async function decorators, and common pitfalls.
Fix: Python mypy Type Error — Incompatible Types and Missing Annotations
How to fix Python mypy type errors — incompatible types in assignment, missing return type, Optional handling, TypedDict, Protocol, overloads, and common mypy configuration mistakes.
Fix: Rails N+1 Query Problem — Too Many Database Queries
How to fix Rails N+1 queries — includes vs joins vs preload vs eager_load, Bullet gem detection, avoiding N+1 in serializers and views, and counter caches.
Fix: React forwardRef Not Working — ref is null or Component Not Exposing Methods
How to fix React forwardRef issues — ref null on custom components, useImperativeHandle setup, forwardRef with TypeScript, class components, and React 19 ref as prop changes.
Fix: React Portal Event Bubbling Not Working — Events Not Reaching Parent
How to fix React Portal event bubbling — understanding Portal event propagation, modal close on outside click, stopPropagation side effects, focus management, and accessibility.
Fix: React StrictMode Double Render — Side Effects Running Twice in Development
How to fix React StrictMode double render issues — understanding intentional double invocation, fixing side effects, useEffect cleanup, external subscriptions, and production behavior.
Fix: React Suspense Not Working — Boundary Not Catching or Fallback Not Showing
How to fix React Suspense boundaries not triggering — lazy() import syntax, use() hook, data fetching libraries, ErrorBoundary vs Suspense, and Next.js loading.tsx.
Fix: Ruby Bundler Version Conflict — Gemfile Requirements Could Not Be Resolved
How to fix Ruby Bundler gem version conflicts — Gemfile.lock resolution, platform-specific gems, bundle update strategies, conflicting transitive dependencies, and Bundler version issues.
Fix: Spring Boot @Transactional Not Rolling Back — Transaction Committed Despite Exception
How to fix Spring @Transactional not rolling back — checked vs unchecked exceptions, self-invocation proxy bypass, rollbackFor, transaction propagation, and nested transactions.
Fix: Svelte Store Subscription Leak — Memory Leak from Unsubscribed Stores
How to fix Svelte store subscription memory leaks — auto-subscription with $, manual unsubscribe, derived store cleanup, custom store lifecycle, and SvelteKit SSR store handling.
Fix: TypeScript Function Overload Error — No Overload Matches This Call
How to fix TypeScript function overload errors — overload signature compatibility, implementation signature, conditional types as alternatives, method overloads in classes, and common pitfalls.
Fix: TypeScript Mapped Type Errors — Type is Not Assignable to Mapped Type
How to fix TypeScript mapped type errors — Partial, Required, Readonly, Record, Pick, Omit, conditional types, template literal types, and distributive behavior.
Fix: Vue Composable Not Reactive — ref and reactive Losing Reactivity After Destructuring
How to fix Vue composable reactivity loss — toRefs for destructuring, returning refs vs raw values, reactive object pitfalls, stale closures, and composable design patterns.
Fix: Vue Composition API Reactivity Lost — Destructured Props or Reactive Object Not Updating
How to fix Vue Composition API reactivity loss — destructuring reactive objects, toRefs, storeToRefs, ref vs reactive, watch vs watchEffect, and template not updating.
Fix: Pinia State Not Reactive — Store Changes Not Updating the Component
How to fix Pinia store state not updating components — storeToRefs for destructuring, $patch for partial updates, avoiding reactive() wrapping, getters vs computed, and SSR hydration.
Fix: Vue Router 404 on Page Refresh — History Mode Returns 404 or Blank Page
How to fix Vue Router 404 errors on page refresh in history mode — server configuration for nginx, Apache, Vite, Express, and Netlify, plus hash mode as a fallback.
Fix: Webpack Dev Server Not Reloading — HMR and Live Reload Not Working
How to fix Webpack dev server not reloading — Hot Module Replacement configuration, watchFiles settings, polling for Docker/WSL, HMR API for custom modules, and port conflicts.
Fix: Webpack Bundle Size Too Large — Reduce JavaScript Bundle for Faster Load Times
How to reduce Webpack bundle size — code splitting, tree shaking, dynamic imports, bundle analysis, moment.js replacement, lodash optimization, and production build configuration.
Fix: Angular Form Validation Not Working — Validators Not Triggering
How to fix Angular form validation not working — Reactive Forms vs Template-Driven, custom validators, async validators, touched/dirty state, and error message display.
Fix: Angular Lazy Loading Not Working — Routes Not Code-Split
How to fix Angular lazy loading not working — loadChildren syntax, standalone components, route configuration mistakes, preloading strategies, and debugging bundle splits.
Fix: Angular RxJS Memory Leak — Subscriptions Not Unsubscribed
How to fix RxJS memory leaks in Angular — unsubscribing from Observables, takeUntilDestroyed, async pipe, subscription management patterns, and detecting leaks with Chrome DevTools.
Fix: AWS Access Denied — IAM Permission Errors and Policy Debugging
How to fix AWS Access Denied errors — understanding IAM policies, using IAM policy simulator, fixing AssumeRole errors, resource-based policies, and SCPs blocking actions.
Fix: Docker Build Cache Invalidated — Slow Builds on Every Run
How to fix Docker layer cache being invalidated on every build — Dockerfile instruction order, COPY optimization, ARG vs ENV, BuildKit cache mounts, and .dockerignore.
Fix: FastAPI Dependency Injection Errors — Dependencies Not Working
How to fix FastAPI dependency injection errors — async dependencies, database sessions, sub-dependencies, dependency overrides in tests, and common DI mistakes.
Fix: GitHub Actions Matrix Strategy Not Working — Jobs Not Running or Failing
How to fix GitHub Actions matrix strategy issues — matrix expansion, include/exclude patterns, failing fast, matrix variable access, and dependent jobs with matrix outputs.
Fix: Go Goroutine Leak, Goroutines That Never Exit
How to find and fix goroutine leaks in Go, detecting leaks with pprof and goleak, blocked channel patterns, context cancellation, and goroutine lifecycle management.
Fix: Go Interface Nil Panic, Non-Nil Interface Holding a Nil Pointer
How to fix the Go interface nil trap, understanding non-nil interfaces with nil pointers, detecting the issue, error interface patterns, and designing APIs to avoid the pitfall.
Fix: Go Concurrent Map Read and Write Panic, fatal error: concurrent map
How to fix Go's concurrent map read and write panic, using sync.RWMutex, sync.Map, atomic operations, and structuring code to avoid shared state.
Fix: Jest Fake Timers Not Working — setTimeout and setInterval Not Advancing
How to fix Jest fake timers not working — useFakeTimers setup, runAllTimers vs advanceTimersByTime, async timers, React testing with act(), and common timer test mistakes.
Fix: Jest Module Mock Not Working — jest.mock() Has No Effect
How to fix Jest module mocks not working — hoisting behavior, ES module mocks, factory functions, mockReturnValue vs implementation, and clearing mocks between tests.
Fix: Kubernetes Secret Not Mounted — Pod Cannot Access Secret Values
How to fix Kubernetes Secrets not being mounted — namespace mismatches, RBAC permissions, volume mount configuration, environment variable injection, and secret decoding issues.
Fix: MySQL Index Not Being Used — Query Optimizer Skipping Indexes
How to fix MySQL indexes not being used by the query optimizer — EXPLAIN output, implicit conversions, function on columns, composite index order, cardinality issues, and forcing indexes.
Fix: NestJS Guard Not Working — canActivate Always Passes or Is Never Called
How to fix NestJS guards not working — applying guards globally vs controller vs method level, JWT AuthGuard, metadata with Reflector, public routes, and guard execution order.
Fix: NestJS Interceptor Not Triggered — Interceptors Not Running
How to fix NestJS interceptors not being called — global vs controller vs method binding, response transformation, async interceptors, execution context, and interceptor ordering.
Fix: Node.js UnhandledPromiseRejection and uncaughtException — Crashing Server
How to handle Node.js uncaughtException and unhandledRejection events — graceful shutdown, error logging, async error boundaries, and keeping servers alive safely.
Fix: Prisma Transaction Error — Transaction Already Closed or Rolled Back
How to fix Prisma transaction errors — interactive transactions vs $transaction array, error handling and rollback, nested transactions, timeout issues, and isolation levels.
Fix: Python asyncio Blocking the Event Loop — Mixing Sync and Async Code
How to fix Python asyncio event loop blocking — using run_in_executor for sync calls, asyncio.to_thread, avoiding blocking I/O in coroutines, and detecting event loop stalls.
Fix: Python Circular Import Error — ImportError and Cannot Import Name
How to fix Python circular import errors — restructuring modules, lazy imports, TYPE_CHECKING guard, dependency injection, and __init__.py import order issues.
Fix: React Hydration Error — Text Content Does Not Match
How to fix React hydration errors — server/client HTML mismatches, useEffect for client-only code, suppressHydrationWarning, dynamic content, and Next.js specific hydration issues.
Fix: TanStack Query (React Query) Returning Stale Data — Cache Not Updating
How to fix TanStack Query returning stale cached data — staleTime, invalidateQueries, query key structure, optimistic updates, and cache synchronization after mutations.
Fix: Redis Pub/Sub Not Working — Messages Not Received by Subscribers
How to fix Redis Pub/Sub issues — subscriber not receiving messages, channel name mismatches, connection handling, pattern subscriptions, and scaling with multiple processes.
Fix: Socket.IO CORS Error — Cross-Origin Connection Blocked
How to fix Socket.IO CORS errors — server-side CORS configuration, credential handling, polling vs WebSocket transport, proxy setup, and common connection failures.
Fix: Terraform Variable Not Set, No Value for Required Variable
How to fix Terraform 'no value for required variable' errors, variable definition files, environment variables, tfvars files, sensitive variables, and variable precedence.
Fix: TypeScript Could Not Find Declaration File, Module Has No Type Information
How to fix TypeScript 'could not find a declaration file for module' errors, installing @types packages, writing custom .d.ts files, module augmentation, and tsconfig paths.
Fix: Vue Computed Property Not Updating — Reactivity Not Triggered
How to fix Vue computed properties not updating — reactive dependency tracking, accessing nested objects, computed setters, watchEffect vs computed, and Vue 3 reactivity pitfalls.
Fix: Vue v-model Not Working on Custom Components — Prop Not Syncing
How to fix Vue v-model on custom components — defineModel, modelValue/update:modelValue pattern, multiple v-model bindings, v-model modifiers, and Vue 2 vs Vue 3 differences.
Fix: Webpack/Vite Path Alias Not Working — Module Not Found with @/ Prefix
How to fix path alias errors in webpack and Vite — configuring resolve.alias, tsconfig paths, babel-plugin-module-resolver, Vite alias configuration, and Jest moduleNameMapper.
Fix: Angular Change Detection Not Working — View Not Updating
How to fix Angular change detection issues — OnPush strategy not triggering, async pipe, markForCheck vs detectChanges, zone.js and zoneless patterns, and manual change detection triggers.
Fix: Celery Task Not Executing — Worker Not Processing Tasks
How to fix Celery tasks not executing — worker configuration, broker connection issues, task routing, serialization errors, and debugging stuck or lost tasks.
Fix: CSS Container Query Not Working — @container and container-type Issues
How to fix CSS container queries not working — setting container-type correctly, understanding containment scope, fixing @container syntax, and handling browser support and specificity issues.
Fix: Django REST Framework 403 Permission Denied
How to fix Django REST Framework 403 Forbidden and permission denied errors — authentication classes, permission classes, IsAuthenticated vs AllowAny, object-level permissions, and CSRF issues.
Fix: Express Async Error Not Being Caught — Unhandled Promise Rejection
How to fix Express async route handlers not passing errors to the error middleware — wrapping async routes, using express-async-errors, global error handlers, and Node.js unhandledRejection events.
Fix: GitHub Actions Docker Build and Push Failing
How to fix GitHub Actions Docker build and push errors — registry authentication, image tagging, layer caching, multi-platform builds, and GHCR vs Docker Hub setup.
Fix: Go context deadline exceeded / context canceled
How to fix Go context.DeadlineExceeded and context.Canceled errors — setting timeouts correctly, propagating context through call chains, handling cancellation, and debugging which operation timed out.
Fix: GraphQL N+1 Query Problem — DataLoader and Batching
How to fix the GraphQL N+1 query problem — understanding why it happens, implementing DataLoader for batching, using query complexity limits, and selecting efficient resolver patterns.
Fix: Kubernetes Pod OOMKilled, Out of Memory Error
How to fix Kubernetes OOMKilled errors, understanding memory limits, finding memory leaks, setting correct resource requests and limits, and using Vertical Pod Autoscaler.
Fix: MySQL Slow Query — Diagnosis and Optimization with EXPLAIN
How to diagnose and fix slow MySQL queries — enabling the slow query log, reading EXPLAIN output, adding indexes, fixing N+1 queries, and optimizing JOINs and ORDER BY.
Fix: NestJS Circular Dependency — forwardRef and Module Design
How to fix NestJS circular dependency errors — using forwardRef, restructuring module dependencies, extracting shared services, and understanding the NestJS module system.
Fix: Next.js App Router Fetch Not Caching or Always Stale
How to fix Next.js App Router fetch caching issues — understanding cache behavior, revalidation with next.revalidate, opting out with no-store, cache tags, and debugging stale data.
Fix: Node.js JavaScript Heap Out of Memory
How to fix Node.js 'JavaScript heap out of memory' — increasing heap size, finding memory leaks with heap snapshots, fixing common leak patterns, and stream-based processing for large data.
Fix: pandas SettingWithCopyWarning — A value is trying to be set on a copy
How to fix pandas SettingWithCopyWarning — understanding chained indexing, using .loc correctly, Copy-on-Write in pandas 2.x, and when the warning indicates a real bug vs a false alarm.
Fix: PostgreSQL Slow Query — Finding and Optimizing with EXPLAIN ANALYZE
How to diagnose and fix slow PostgreSQL queries — reading EXPLAIN ANALYZE output, adding the right indexes, fixing N+1 queries, optimizing joins, and using pg_stat_statements.
Fix: Python logging Not Showing Output
How to fix Python logging not displaying messages — log level misconfiguration, missing handlers, root logger vs named loggers, basicConfig not working, and logging in libraries vs applications.
Fix: React Native Android Build Failed
How to fix React Native Android build failures — SDK version mismatches, Gradle errors, duplicate module issues, Metro bundler problems, and NDK configuration for common build errors.
Fix: React Server Components Error — useState, Event Handlers, and Client Boundary Issues
How to fix React Server Components errors — useState and hooks in server components, missing 'use client' directive, async component patterns, serialization errors, and client/server boundary mistakes.
Fix: Redux State Not Updating — Component Not Re-rendering
How to fix Redux state not updating in components — mutating state directly, stale selectors, missing immer patterns in Redux Toolkit, useSelector mistakes, and debugging with Redux DevTools.
Fix: Svelte Store Not Updating — Reactive Store Issues
How to fix Svelte store not updating the UI — writable vs readable stores, derived stores, subscribe pattern, store mutation vs assignment, and custom store patterns.
Fix: TypeORM QueryFailedError and Entity Not Found
How to fix TypeORM QueryFailedError, entity not found errors, relation issues, missing migrations, and connection configuration problems in Node.js and NestJS applications.
Fix: Vue Router Navigation Guard Not Working — beforeEach and Route Guards
How to fix Vue Router navigation guards not working — beforeEach, beforeEnter, in-component guards, async guards, redirect loops, and route meta authentication patterns.
Fix: Webpack Bundle Too Large — Chunk Size Warning
How to reduce Webpack bundle size — code splitting, lazy loading, tree shaking, analyzing the bundle with webpack-bundle-analyzer, replacing heavy dependencies, and configuring splitChunks.
Fix: AWS ECS Task Failed to Start
How to fix ECS tasks that fail to start — port binding errors, missing IAM permissions, Secrets Manager access, essential container exit codes, and health check failures.
Fix: Axios Network Error — Request Failed with Status Code 0
How to fix Axios 'Network Error' with no status code — CORS blocks, SSL certificate issues, request timeout, no internet connection, and debugging with interceptors.
Fix: Docker Compose Services Can't Connect to Each Other
How to fix Docker Compose networking issues — services can't reach each other by hostname, port mapping confusion, network aliases, depends_on timing, and host vs container port differences.
Fix: Docker Container Keeps Restarting
How to fix a Docker container that keeps restarting — reading exit codes, debugging CrashLoopBackOff, fixing entrypoint errors, missing env vars, out-of-memory kills, and restart policy misconfiguration.
Fix: Docker Multi-Stage Build COPY --from Failed
How to fix Docker multi-stage build errors — COPY --from stage not found, wrong stage name, artifacts not at expected path, and BuildKit caching issues.
Fix: ESLint no-unused-vars False Positives and Configuration
How to fix ESLint no-unused-vars false positives — TypeScript types, destructuring ignores, React imports, function arguments, and configuring the rule to match your codebase patterns.
Fix: Express req.body Is undefined
How to fix req.body being undefined in Express — missing body-parser middleware, wrong Content-Type header, middleware order issues, and multipart form data handling.
Fix: Flask Route Returns 404 Not Found
How to fix Flask routes returning 404 — trailing slash redirect, Blueprint prefix issues, route not registered, debug mode, and common URL rule mistakes.
Fix: Flask CORS Not Working
How to fix CORS errors in Flask — installing flask-cors correctly, handling preflight OPTIONS requests, configuring origins with credentials, route-specific CORS, and debugging missing headers.
Fix: Git Keeps Asking for Username and Password
How to fix Git repeatedly prompting for credentials — credential helper not configured, HTTPS vs SSH, expired tokens, macOS keychain issues, and setting up a Personal Access Token.
Fix: GitHub Actions Environment Variables Not Available Between Steps
How to fix GitHub Actions env vars and outputs not persisting between steps — GITHUB_ENV, GITHUB_OUTPUT, job outputs, and why echo >> $GITHUB_ENV is required.
Fix: Go panic: runtime error: invalid memory address or nil pointer dereference
How to fix Go nil pointer dereference panics — checking for nil before use, nil interface traps, nil map writes, receiver methods on nil, and defensive nil handling patterns.
Fix: Hibernate LazyInitializationException — Could Not Initialize Proxy
How to fix Hibernate LazyInitializationException — loading lazy associations outside an active session, fetch join, @Transactional scope, DTO projection, and Open Session in View.
Fix: Jest Snapshot Outdated, 1 snapshot obsolete
How to fix Jest snapshot failures, updating outdated snapshots, removing obsolete ones, fixing inline snapshots, preventing brittle snapshot tests, and managing snapshots in CI.
Fix: Linux OOM Killer Killing Processes (Out of Memory)
How to fix Linux OOM killer terminating processes, reading oom_kill logs, adjusting oom_score_adj, adding swap, tuning vm.overcommit, and preventing memory leaks.
Fix: Next.js CORS Error on API Routes
How to fix CORS errors in Next.js API routes — adding Access-Control headers, handling preflight OPTIONS requests, configuring next.config.js headers, and avoiding common proxy mistakes.
Fix: pandas merge() Key Error and Duplicate Columns (_x, _y)
How to fix pandas merge and join errors — KeyError on merge key, duplicate _x/_y columns, unexpected row counts, suffixes, and how to validate merge results.
Fix: PostgreSQL "sorry, too many clients already"
How to fix PostgreSQL 'sorry, too many clients already' error — checking active connections, using connection pooling with PgBouncer, tuning max_connections, fixing ORM pool settings, and finding connection leaks.
Fix: Prisma Unique Constraint Failed on the Fields
How to fix Prisma's 'Unique constraint failed on the fields' error — finding which field caused it, handling upserts, race conditions, and bulk insert deduplication.
Fix: Pydantic ValidationError — Field Required / Value Not Valid
How to fix Pydantic ValidationError in Python — missing required fields, wrong types, custom validators, handling optional fields, v1 vs v2 API differences, and debugging complex nested models.
Fix: React useEffect Runs Twice in Development
Why React useEffect runs twice in development with Strict Mode, how to handle the double invocation correctly, when to add cleanup functions, and when the double-run actually reveals a real bug.
Fix: TypeScript Decorators Not Working (experimentalDecorators)
How to fix TypeScript decorators not applying — experimentalDecorators not enabled, emitDecoratorMetadata missing, reflect-metadata not imported, and decorator ordering issues.
Fix: TypeScript Enum Not Working — const enum, isolatedModules, and Runtime Issues
How to fix TypeScript enum problems — const enum with isolatedModules, enums not available at runtime, string vs numeric enums, and migrating to union types or as const objects.
Fix: Vite Environment Variables Not Working
How to fix Vite environment variables showing as undefined — missing VITE_ prefix, wrong .env file for the mode, import.meta.env vs process.env, TypeScript types, and SSR differences.
Fix: AWS CloudWatch Logs Not Appearing
How to fix AWS CloudWatch logs not showing up — IAM permissions missing, log group not created, log stream issues, CloudWatch agent misconfiguration, and Lambda log delivery delays.
Fix: CSS Custom Properties (Variables) Not Working or Not Updating
How to fix CSS custom properties not applying — wrong scope, missing fallback values, JavaScript not setting variables on the right element, and how CSS variables interact with media queries and Shadow DOM.
Fix: Spring Boot "The dependencies of some of the beans in the application context form a cycle"
How to fix Spring Boot circular dependency errors — BeanCurrentlyInCreationException, refactoring to break cycles, @Lazy injection, setter injection, and @PostConstruct patterns.
Fix: Spring Security Returning 403 Forbidden Unexpectedly
How to fix Spring Security 403 Forbidden errors, CSRF token missing, incorrect security configuration, method security blocking requests, and how to debug the Spring Security filter chain.
Fix: Kubernetes ConfigMap Changes Not Reflected in Running Pods
How to fix Kubernetes ConfigMap updates not reaching running pods — why pods don't see updated values, how to trigger restarts, use live volume mounts, and automate ConfigMap rollouts with Reloader.
Fix: MongoDB "not primary" Write Error (Replica Set)
How to fix MongoDB 'not primary' errors when writing to a replica set, read preference misconfiguration, connecting to a secondary, replica set elections, and write concern settings.
Fix: Certbot Certificate Renewal Failed (Let's Encrypt)
How to fix Certbot certificate renewal failures — domain validation errors, port 80 blocked, nginx config issues, permissions, and automating renewals with systemd or cron.
Fix: Node.js Crashing with UnhandledPromiseRejection (--unhandled-rejections)
How to fix Node.js UnhandledPromiseRejectionWarning and process crashes — why unhandled promise rejections crash Node.js 15+, how to add global handlers, find the source of the rejection, and fix async error handling.
Fix: Poetry Dependency Conflict (SolverProblemError / No Solution Found)
How to fix Poetry dependency resolution errors — SolverProblemError when adding packages, conflicting version constraints, how to diagnose dependency trees, and workarounds for incompatible packages.
Fix: Python venv Using Wrong Python Version
How to fix Python virtual environments using the wrong Python version — venv picking system Python instead of pyenv, specifying the interpreter path, and verifying the active environment.
Fix: AWS ECR Authentication Failed (docker login and push Errors)
How to fix AWS ECR authentication errors — no basic auth credentials, token expired, permission denied on push, and how to authenticate correctly from CI/CD pipelines and local development.
Fix: Django Migration Conflict (Conflicting Migrations Cannot Be Applied)
How to fix Django migration conflicts — why multiple leaf migrations conflict, how to merge conflicting migrations, resolve dependency chains, and set up a team workflow to prevent migration conflicts.
Fix: Docker Build ARG Not Available in RUN Commands
How to fix Docker build ARG variables that are empty or undefined inside RUN commands — why ARG scope is limited, how ARG and ENV interact, multi-stage build ARG scoping, and secrets that shouldn't use ARG.
Fix: GitHub Actions if Condition Not Working (Steps and Jobs Being Skipped or Always Running)
How to fix GitHub Actions if conditions that don't evaluate correctly — why steps are skipped or always run, how to use context expressions, fix boolean checks, and handle job outputs in conditions.
Fix: GraphQL 400 Bad Request Error (Query Syntax and Variable Errors)
How to fix GraphQL 400 Bad Request errors — malformed query syntax, variable type mismatches, missing required fields, schema validation failures, and how to debug GraphQL errors from Apollo and fetch.
Fix: Kubernetes Ingress Not Working (404, 502, or Traffic Not Routing)
How to fix Kubernetes Ingress not routing traffic — why Ingress returns 404 or 502, how to configure annotations correctly, debug ingress-nginx and AWS ALB Ingress Controller, and verify backend service health.
Fix: Mongoose ValidationError — Document Failed to Save
How to fix Mongoose ValidationError when saving documents — required field errors, type cast failures, custom validator errors, and how to handle validation in Express APIs properly.
Fix: Next.js Middleware Not Running (middleware.ts Not Intercepting Requests)
How to fix Next.js middleware not executing — wrong file location, matcher config errors, middleware not intercepting API routes, and how to debug middleware execution in Next.js 13 and 14.
Fix: pnpm Peer Dependency Errors (Missing or Incompatible Peer Dependencies)
How to fix pnpm peer dependency errors — why pnpm is stricter than npm about peer deps, how to resolve missing peers, configure peerDependencyRules, and handle incompatible version ranges.
Fix: Python dataclass Mutable Default Value Error (ValueError / TypeError)
How to fix Python dataclass mutable default errors — why lists, dicts, and sets cannot be default field values, how to use field(default_factory=...), and common dataclass pitfalls with inheritance and ClassVar.
Fix: React Query (TanStack Query) Infinite Refetching Loop
How to fix React Query refetching infinitely — why useQuery keeps fetching, how object and array dependencies cause loops, how to stabilize queryKey, and configure refetch behavior correctly.
Fix: Socket.IO Not Connecting (CORS, Transport, and Namespace Errors)
How to fix Socket.IO connection failures — CORS errors, transport fallback issues, wrong namespace, server not emitting to the right room, and how to debug Socket.IO connections in production.
Fix: Spring Boot Failed to Configure DataSource (DataSource Auto-Configuration Error)
How to fix Spring Boot 'Failed to configure a DataSource' errors, missing URL property, driver class not found, connection refused, and how to correctly configure datasource properties for MySQL, PostgreSQL, and H2.
Fix: TypeScript isolatedModules Errors (const enum, type-only imports)
How to fix TypeScript isolatedModules errors — why const enum fails with Babel and Vite, how to replace const enum, fix re-exported types, and configure isolatedModules correctly for your build tool.
Fix: Vitest Setup Not Working (setupFiles, Mocks, and Global Config Issues)
How to fix Vitest configuration not taking effect — why setupFiles don't run, globals are undefined, mocks don't work, and how to configure Vitest correctly for React, Vue, and Node.js projects.
Fix: AWS RDS Connection Timed Out from Lambda or EC2
How to fix AWS RDS connection timeout errors from Lambda functions and EC2 instances, security group configuration, VPC settings, connection pooling, and RDS Proxy setup for Lambda.
Fix: Docker Compose Environment Variables Not Loading from .env File
How to fix Docker Compose not loading environment variables from .env files — why variables are empty or undefined inside containers, the difference between env_file and variable substitution, and how to debug env var issues.
Fix: ESLint import/no-unresolved Error (Module Exists but ESLint Can't Find It)
How to fix ESLint's import/no-unresolved errors when modules actually resolve correctly — configure eslint-import-resolver-typescript, fix path alias settings, and handle node_modules that ESLint cannot find.
Fix: GitHub Actions Cache Not Working (Cache Miss on Every Run)
How to fix GitHub Actions cache not restoring — why actions/cache always misses, how to construct correct cache keys, debug cache hits and misses, and optimize caching for npm, pip, and Gradle.
Fix: jest.mock() Not Working — Module Not Being Replaced in Tests
How to fix jest.mock() not intercepting module calls — why mocks are ignored, how to correctly mock ES modules, default exports, named exports, and fix hoisting issues in Jest tests.
Fix: Next.js Build Failed (next build Errors and How to Fix Them)
How to fix Next.js build failures — TypeScript errors blocking production builds, module resolution failures, missing environment variables, static generation errors, and common next build crash causes.
Fix: Prisma Migration Failed (migrate dev / migrate deploy Errors)
How to fix Prisma migration errors — migrate dev failing with schema drift, migrate deploy errors in production, database out of sync, and how to safely reset or resolve migration conflicts.
Fix: Python requests.get() Hanging, Timeout Not Working
How to fix Python requests hanging forever, why requests.get() ignores timeout, how to set connect and read timeouts correctly, use session-level timeouts, and handle timeout exceptions properly.
Fix: Redis Key Not Expiring (TTL / EXPIRE Not Working)
How to fix Redis keys that never expire — why EXPIRE commands are silently overwritten, how SET options replace TTL, how to inspect key TTL, and how to prevent accidental TTL removal in your application.
Fix: Vite Build Chunk Size Warning (Some Chunks Are Larger Than 500 kB)
How to fix Vite's chunk size warning — why bundles exceed 500 kB, how to split code with dynamic imports and manualChunks, configure the chunk size limit, and optimize your Vite production build.
Fix: CSS Animation Not Working (@keyframes Has No Effect)
How to fix CSS animations not working — @keyframes not applying, animation paused, transform conflicts, reduced motion settings, and common animation property mistakes.
Fix: Elasticsearch index_not_found_exception (Index Does Not Exist)
How to fix Elasticsearch index_not_found_exception errors — why index operations fail with 404, how to create indices correctly, manage index aliases, and handle missing indices in production.
Fix: Undo git reset --hard and Recover Lost Commits
How to undo git reset --hard and recover lost commits using git reflog — step-by-step recovery for accidentally reset branches, lost work, and dropped stashes.
Fix: JavaScript NaN === NaN Returns false (NaN Comparison Bugs)
How to fix JavaScript NaN comparison bugs — why NaN !== NaN, the difference between isNaN() and Number.isNaN(), and how to correctly check for NaN in conditionals and array operations.
Fix: Linux No Space Left on Device (Disk Full Error)
How to fix 'No space left on device' errors on Linux, find what is consuming disk space with df and du, clean up logs, Docker images, old kernels, and temporary files, and prevent disk full situations.
Fix: MySQL Deadlock Found When Trying to Get Lock
How to fix MySQL 'Deadlock found when trying to get lock; try restarting transaction' — diagnosing deadlock causes, using SHOW ENGINE INNODB STATUS, and preventing deadlocks with consistent lock ordering.
Fix: React Native Metro Bundler Failed to Start or Bundle
How to fix React Native Metro bundler errors — unable to resolve module, EMFILE too many open files, port already in use, transform cache errors, and Metro failing to start on iOS or Android.
Fix: Stripe Webhook Signature Verification Failed
How to fix Stripe webhook signature verification errors — why Stripe-Signature header validation fails, how to correctly pass the raw request body, and how to debug webhook delivery in the Stripe dashboard.
Fix: Vue 3 Reactive Data Not Updating (ref/reactive Not Triggering Re-render)
How to fix Vue 3 reactive data not updating the UI — why ref and reactive lose reactivity, how to correctly mutate reactive state, and common pitfalls with destructuring and nested objects.
Fix: AWS EC2 SSH Connection Refused or Timed Out
How to fix AWS EC2 SSH connection refused or timed out errors — security group rules, key pair issues, sshd not running, wrong username, and network ACL misconfigurations.
Fix: CSS position: sticky Not Working
How to fix CSS position sticky not working — element scrolls away instead of sticking, caused by overflow hidden on a parent, missing top value, wrong stacking context, or incorrect height on the container.
Fix: JavaScript Closure in Loop — All Callbacks Get the Same Value
How to fix the JavaScript closure loop bug where all event handlers or setTimeout callbacks return the same value — using let, IIFE, bind, or forEach instead of var in loops.
Fix: Kubernetes exceeded quota / Pod Stuck in Pending Due to Resource Quota
How to fix Kubernetes 'exceeded quota' errors — pods stuck in Pending because namespace resource quotas are exhausted, missing resource requests, and LimitRange defaults.
Fix: EMFILE Too Many Open Files / ulimit Error on Linux
How to fix EMFILE too many open files errors on Linux and Node.js — caused by low ulimit file descriptor limits, file handle leaks, and how to increase limits permanently.
Fix: Nginx WebSocket Proxy Not Working (101 Switching Protocols Failed)
How to fix Nginx WebSocket proxying not working — 101 Switching Protocols fails, connections drop after 60 seconds, missing Upgrade headers, and SSL WebSocket configuration.
Fix: Python threading Not Running in Parallel (GIL Limitations)
How to fix Python threading not achieving parallelism due to the GIL — when to use multiprocessing, concurrent.futures, or asyncio instead, and what the GIL actually blocks.
Fix: Python multiprocessing Not Working (freeze_support, Pickle Errors, Zombie Processes)
How to fix Python multiprocessing not working, freeze_support error on Windows, pickle errors with lambdas, zombie processes, and Pool hanging indefinitely.
Fix: React.memo Not Preventing Re-renders
How to fix React.memo not working — components still re-rendering despite being wrapped in memo, caused by new object/function references, missing useCallback, and incorrect comparison functions.
Fix: TypeScript Generic Type Constraint Errors
How to fix TypeScript generic constraint errors — Type 'X' does not satisfy the constraint 'Y', generic inference failures, constrained generics with extends, and conditional types.
Fix: CSS Grid Not Working (display: grid Has No Effect)
How to fix CSS Grid not working — grid-template-columns has no effect, grid items not placing correctly, implicit vs explicit grid confusion, and common grid layout debugging techniques.
Fix: Docker Compose depends_on Not Waiting for Service to Be Ready
How to fix Docker Compose depends_on not working — services start in order but the app still crashes because depends_on only waits for container start, not service readiness. Includes healthcheck solutions.
Fix: .gitignore Not Working (Files Still Being Tracked)
How to fix .gitignore not working — files still showing in git status after being added to .gitignore, caused by already-tracked files, wrong syntax, nested gitignore rules, and cache issues.
Fix: Cron Job Not Running on Linux
How to fix cron jobs not running on Linux — caused by PATH issues, missing newlines, permission errors, environment variables not set, and cron daemon not running.
Fix: Next.js Environment Variables Returning undefined
How to fix Next.js environment variables returning undefined — NEXT_PUBLIC prefix rules, server vs client context, .env file loading order, and runtime vs build-time variable access.
Fix: Python asyncio Not Running / async Functions Not Executing
How to fix Python asyncio not running — coroutines never executing, RuntimeError no running event loop, mixing sync and async code, and common async/await mistakes in Python.
Fix: React.lazy and Suspense Errors (Element Type Invalid, Loading Chunk Failed)
How to fix React.lazy and Suspense errors — Element type is invalid, A React component suspended while rendering, Loading chunk failed, and lazy import mistakes with named vs default exports.
Fix: TypeScript Path Aliases Not Working (Cannot Find Module '@/...')
How to fix TypeScript path aliases not resolving — tsconfig paths configured but imports still fail at runtime, in Jest, or after building with webpack, Vite, or ts-node.
Fix: Webpack HMR (Hot Module Replacement) Not Working
How to fix Webpack Hot Module Replacement not updating the browser — HMR connection lost, full page reloads instead of hot updates, and HMR breaking in Docker or behind a proxy.
Fix: CSS Flexbox Not Working (display: flex Has No Effect)
How to fix CSS Flexbox not working — why display flex has no effect, flex children not aligning, flex-grow not stretching, and how to debug common Flexbox layout issues.
Fix: git fatal: A branch named 'x' already exists
How to fix 'git fatal: A branch named already exists' when creating or renaming branches, including local conflicts, remote tracking branches, and worktree issues.
Fix: UnhandledPromiseRejectionWarning / UnhandledPromiseRejection
How to fix UnhandledPromiseRejectionWarning in Node.js and unhandled promise rejection errors in JavaScript caused by missing catch handlers, async/await mistakes, and event emitter errors.
Fix: Nginx location Block Not Matching (Wrong Route Served)
How to fix Nginx location blocks not matching, caused by prefix vs regex priority, trailing slash issues, root vs alias confusion, and try_files misconfiguration.
Fix: Python SSL: CERTIFICATE_VERIFY_FAILED
How to fix Python SSL CERTIFICATE_VERIFY_FAILED error caused by missing root certificates on macOS, expired system certs, corporate proxies, and self-signed certificates in requests, urllib, and httpx.
Fix: VS Code Remote SSH Could Not Establish Connection
How to fix VS Code Remote SSH 'Could not establish connection' errors — caused by missing server files, SSH config issues, firewall blocks, and VS Code Server installation failures.
Fix: ASP.NET 500 Internal Server Error
Fix ASP.NET 500 Internal Server Error by enabling developer exception pages, fixing DI registration, connection strings, and middleware configuration.
Fix: Celery Task Not Received or Not Executing
Fix Celery tasks not being received or executed by resolving broker connections, autodiscovery issues, task name mismatches, and worker configuration.
Fix: Elasticsearch Cluster Health Red Status
Fix Elasticsearch cluster health red status by resolving unassigned shards, disk watermark issues, node failures, and shard allocation problems.
Fix: Electron 'require' Is Not Defined Error
Fix the Electron 'require is not defined' error caused by contextIsolation, nodeIntegration changes, and learn to use preload scripts and contextBridge.
Fix: GitHub Actions Runner Failed to Start or Connect
Fix GitHub Actions self-hosted runner failures including connection issues, version mismatches, and registration problems with step-by-step solutions.
Fix: Heroku H10 App Crashed Error
Fix the Heroku H10 App Crashed error by fixing your Procfile, PORT binding, missing dependencies, and build scripts with step-by-step solutions.
Fix: Pandas SettingWithCopyWarning
Learn how to fix the Pandas SettingWithCopyWarning by using .loc[], .copy(), and avoiding chained indexing in your DataFrame operations.
Fix: RabbitMQ Connection Refused Error
Fix RabbitMQ connection refused errors caused by service issues, port mismatches, credential problems, and Docker networking with step-by-step solutions.
Fix: Sass Error - Undefined Variable
Fix the Sass undefined variable error caused by @use vs @import migration, variable scope issues, and dart-sass namespace changes with clear solutions.
Fix: Vercel Deployment Failed - Common Causes and Solutions
Fix Vercel deployment failures caused by build errors, environment variables, serverless function limits, and dependency issues with step-by-step solutions.
Fix: Angular ExpressionChangedAfterItHasBeenCheckedError
How to fix ExpressionChangedAfterItHasBeenCheckedError in Angular caused by change detection timing issues, lifecycle hooks, async pipes, and parent-child data flow.
Fix: AWS Lambda Unable to import module / Runtime.ImportModuleError
How to fix the AWS Lambda Runtime.ImportModuleError and Unable to import module error caused by wrong handler paths, missing dependencies, layer issues, and packaging problems.
Fix: CMake Could Not Find Package Configuration File
How to fix the CMake error 'Could not find a package configuration file' for find_package, covering CMAKE_PREFIX_PATH, dev packages, vcpkg, Conan, module mode, toolchain files, and cross-compilation.
Fix: C# async deadlock — Task.Result and .Wait() hanging forever
How to fix the C# async/await deadlock caused by Task.Result and .Wait() blocking the synchronization context in ASP.NET, WPF, WinForms, and library code.
Fix: Docker container health status unhealthy
How to fix Docker container health check failing with unhealthy status, including HEALTHCHECK syntax, timing issues, missing curl/wget, endpoint problems, and Compose healthcheck configuration.
Fix: ECONNRESET Socket Hang Up Error in Node.js
How to fix the ECONNRESET and socket hang up errors in Node.js caused by server timeouts, keep-alive misconfiguration, proxy issues, large request bodies, SSL/TLS failures, and connection pool exhaustion.
Fix: Firebase Permission Denied Error
How to fix the Firebase 'permission denied' or 'Missing or insufficient permissions' error in Firestore and Realtime Database. Covers security rules, authentication state, custom claims, Admin SDK, rule simulators, time-based rules, and document-level permissions.
Fix: Git submodule update failed / fatal: not a git repository
Resolve Git submodule update and init failures including 'fatal: not a git repository', path conflicts, URL mismatches, shallow clone issues, and CI/CD checkout problems.
Fix: Gradle Could Not Resolve Dependencies Error
How to fix Gradle's 'Could not resolve all dependencies' error caused by missing repositories, offline mode, proxy issues, version conflicts, and corrupted cache.
Fix: Java ClassCastException: class X cannot be cast to class Y
How to fix Java ClassCastException by using instanceof checks, fixing generic type erasure, resolving ClassLoader conflicts, correcting raw types, and using pattern matching in Java 16+.
Fix: MongoDB E11000 duplicate key error collection
How to fix the MongoDB E11000 duplicate key error by identifying duplicate fields, fixing index conflicts, using upserts, handling null values, and resolving race conditions.
Fix: PHP Warning: Undefined array key (Undefined index)
Fix the PHP warning Undefined array key, Undefined index, and Trying to access array offset on null by checking keys, using the null coalescing operator, and handling PHP 8 strictness.
Fix: PowerShell Script Cannot Be Loaded Because Running Scripts Is Disabled
How to fix 'cannot be loaded because running scripts is disabled on this system' in PowerShell by changing the execution policy with Set-ExecutionPolicy, fixing Group Policy restrictions, and bypassing for single scripts.
Fix: Python TypeError: unhashable type: 'list'
Learn why Python raises TypeError unhashable type list, dict, or set and how to fix it when using dictionary keys, sets, groupby, dataclasses, and custom classes.
Fix: Python ValueError: Too Many Values to Unpack
Learn why Python raises ValueError too many values to unpack and how to fix it when unpacking tuples, iterating dictionaries, parsing files, and using zip or enumerate.
Fix: React Warning: Failed prop type
How to fix the React 'Warning: Failed prop type' error. Covers wrong prop types, missing required props, children type issues, shape and oneOf PropTypes, migrating to TypeScript, default props, and third-party component mismatches.
Fix: SQLite Database Is Locked Error
How to fix the SQLite 'database is locked' error caused by concurrent writes, long-running transactions, missing WAL mode, busy timeout, and unclosed connections.
Fix: Tailwind CSS Classes Not Applying
How to fix Tailwind CSS classes not applying to your HTML elements. Covers content config paths, purge and safelist, class conflicts and specificity, dynamic class names, PostCSS config, @apply issues, dark mode config, and JIT mode problems.
Fix: Xcode Build Failed - Common Causes and Solutions
How to fix Xcode build failed errors including clean build folder, derived data, provisioning profiles, code signing, Swift version mismatch, CocoaPods, SPM, architecture, and missing framework issues.
Fix: Angular NullInjectorError: No provider for X
How to fix Angular NullInjectorError No provider for service caused by missing providers, wrong module imports, standalone components, and lazy-loaded module issues.
Fix: AWS CloudFormation stack in ROLLBACK_COMPLETE or CREATE_FAILED state
How to fix AWS CloudFormation ROLLBACK_COMPLETE and CREATE_FAILED errors caused by IAM permissions, resource limits, invalid parameters, and dependency failures.
Fix: C# Cannot implicitly convert type 'X' to 'Y'
How to fix C# cannot implicitly convert type error caused by type mismatches, nullable types, async return values, LINQ result types, and generic constraints.
Fix: C# TaskCanceledException: A task was canceled
How to fix C# TaskCanceledException A task was canceled caused by HttpClient timeouts, CancellationToken, request cancellation, and Task.WhenAll failures.
Fix: Django Forbidden (403) CSRF verification failed
How to fix Django 403 CSRF verification failed error caused by missing CSRF tokens, AJAX requests, cross-origin issues, HTTPS misconfig, and session problems.
Fix: Docker build sending large build context / slow Docker build
How to fix Docker build sending large build context caused by missing .dockerignore, node_modules in context, large files, and inefficient Dockerfile layers.
Fix: Docker Compose Service failed to build / ERROR building
How to fix Docker Compose Service failed to build errors caused by wrong Dockerfile paths, YAML syntax issues, build args, platform mismatches, and network failures.
Fix: Docker exec /entrypoint.sh: no such file or directory
How to fix Docker entrypoint not found error caused by wrong file path, Windows line endings, missing shebang, wrong base image, and multi-stage build issues.
Fix: Express Cannot GET /route (404 Not Found)
How to fix Express.js Cannot GET route 404 error caused by wrong route paths, missing middleware, route order issues, static files, and router mounting problems.
Fix: FastAPI 422 Unprocessable Entity (validation error)
How to fix FastAPI 422 Unprocessable Entity error caused by wrong request body format, missing fields, type mismatches, query parameter errors, and Pydantic validation.
Fix: git cherry-pick error: could not apply commit (conflict)
How to fix git cherry-pick conflict errors caused by diverged branches, overlapping changes, missing context, renamed files, and merge commits.
Fix: git error: src refspec 'main' does not match any
How to fix git error src refspec main does not match any caused by empty repos, wrong branch name, no commits, typos, and default branch mismatch.
Fix: Git remote rejected — file exceeds GitHub's file size limit of 100.00 MB
Resolve the GitHub push error when a file exceeds the 100 MB size limit by removing the large file from history, using Git LFS, or cleaning your repository with BFG Repo Cleaner.
Fix: Go fatal error: all goroutines are asleep - deadlock!
How to fix Go fatal error all goroutines are asleep deadlock caused by unbuffered channels, missing goroutines, WaitGroup misuse, and channel direction errors.
Fix: Go panic: runtime error: index out of range
How to fix Go panic runtime error index out of range caused by empty slices, off-by-one errors, nil slices, concurrent access, and missing bounds checks.
Fix: Go cannot use X (type Y) as type Z in argument
How to fix Go 'cannot use as type' error caused by type mismatches, interface satisfaction, pointer vs value receivers, type conversions, and generic constraints.
Fix: Go undefined: variable (or function)
How to fix Go undefined error caused by undeclared variables, wrong package scope, unexported names, missing imports, build tags, and file organization issues.
Fix: Java ConcurrentModificationException
How to fix Java ConcurrentModificationException caused by modifying a collection while iterating, HashMap concurrent access, stream operations, and multi-threaded collection usage.
Fix: Java NoSuchMethodError
How to fix Java NoSuchMethodError caused by classpath conflicts, incompatible library versions, wrong dependency scope, shaded JARs, and compile vs runtime version mismatches.
Fix: Java java.lang.IllegalArgumentException
How to fix Java IllegalArgumentException caused by null arguments, invalid enum values, negative numbers, wrong format strings, and Spring/Hibernate validation failures.
Fix: Java java.lang.NullPointerException
How to fix Java NullPointerException by reading stack traces, adding null checks, using Optional, fixing uninitialized variables, avoiding null returns, handling auto-unboxing, and using static analysis annotations.
Fix: Spring BeanCreationException: Error creating bean with name
How to fix Spring BeanCreationException error creating bean caused by missing dependencies, circular references, wrong annotations, configuration errors, and constructor issues.
Fix: Java StackOverflowError – Infinite Recursion, Circular References, and Stack Size
How to fix java.lang.StackOverflowError caused by infinite recursion, circular references in toString or equals, JPA bidirectional relationships, and Spring circular dependencies.
Fix: FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
How to fix the JavaScript heap out of memory error by increasing Node.js memory limits, fixing memory leaks, and optimizing builds in webpack, Vite, and Docker.
Fix: TypeError: x is not a function
How to fix JavaScript TypeError is not a function caused by wrong variable types, missing imports, overwritten variables, incorrect method names, and callback issues.
Fix: kubectl apply error validating / is invalid
How to fix kubectl apply errors like 'error validating', 'is invalid', and 'error when creating' caused by YAML syntax issues, deprecated APIs, missing fields, and more.
Fix: Kubernetes Pod stuck in Pending state
How to fix Kubernetes Pod stuck in Pending state caused by insufficient resources, unschedulable nodes, PVC issues, node selectors, taints, and resource quotas.
Fix: Maven Could Not Resolve Dependencies - Failed to Read Artifact Descriptor
How to fix Maven's 'Could not resolve dependencies' and 'Failed to read artifact descriptor' errors caused by corrupted cache, proxy settings, missing repositories, and version conflicts.
Fix: MySQL ERROR 1205: Lock wait timeout exceeded
How to fix MySQL ERROR 1205 Lock wait timeout exceeded caused by long-running transactions, row-level locks, missing indexes, deadlocks, and InnoDB lock contention.
Fix: Next.js 500 Internal Server Error
How to fix the Next.js 500 Internal Server Error by checking server logs, fixing getServerSideProps, API routes, environment variables, database connections, middleware, and deployment issues.
Fix: Next.js API route 404 Not Found or not responding
How to fix Next.js API route 404 not found errors caused by wrong file paths, App Router vs Pages Router confusion, incorrect exports, and deployment issues.
Fix: Nginx 413 Request Entity Too Large
How to fix the Nginx 413 Request Entity Too Large error when uploading files by adjusting client_max_body_size, PHP limits, Node.js body parser, proxy buffers, Docker ingress, and more.
Fix: Nginx SSL: error:0A00006C:SSL routines::bad key / SSL handshake failed
How to fix Nginx SSL handshake failed and certificate errors caused by mismatched keys, wrong certificate chain, expired certs, TLS version issues, and permission problems.
Fix: npm ERR! code E404 – Not Found (package not found in registry)
How to fix npm ERR code E404 not found error caused by typos, private registries, scoped packages, deleted packages, and authentication issues.
Fix: npm ERR! Could not resolve peer dependency conflict
How to fix the npm ERR! Could not resolve peer dependency conflict error. Covers --legacy-peer-deps, --force, npm overrides, peerDependenciesMeta, React version conflicts, and debugging with npm ls.
Fix: PHP Fatal error: Allowed memory size of X bytes exhausted
How to fix PHP Fatal error Allowed memory size exhausted caused by memory limits, large datasets, memory leaks, recursive functions, and inefficient queries.
Fix: PostgreSQL permission denied for table (or relation, schema, sequence)
How to fix the PostgreSQL error 'permission denied for table' by granting privileges, fixing default permissions, resolving schema and ownership issues, RLS policies, and role inheritance.
Fix: Python RuntimeError: no running event loop / This event loop is already running
How to fix Python asyncio RuntimeError no running event loop and event loop already running caused by mixing sync and async code, Jupyter, and wrong loop management.
Fix: Python AttributeError: 'NoneType' object has no attribute
How to fix Python AttributeError NoneType object has no attribute caused by functions returning None, method chaining, failed lookups, uninitialized variables, and missing return statements.
Fix: Python requests.exceptions.ConnectionError: Max retries exceeded
How to fix Python requests ConnectionError Max retries exceeded caused by wrong URL, DNS failure, server down, SSL errors, connection pool exhaustion, and firewall blocks.
Fix: Python FileNotFoundError: [Errno 2] No such file or directory
How to fix Python FileNotFoundError No such file or directory caused by relative vs absolute paths, wrong working directory, missing files, pathlib usage, and Docker container file access.
Fix: Python IndexError: list index out of range
How to fix Python IndexError list index out of range caused by empty lists, off-by-one errors, wrong loop bounds, deleted elements, and negative indexing mistakes.
Fix: Python json.decoder.JSONDecodeError: Expecting value
How to fix Python JSONDecodeError Expecting value caused by empty responses, HTML error pages, invalid JSON, BOM characters, and API errors.
Fix: Python KeyError: 'key_name'
How to fix Python KeyError caused by missing dictionary keys, JSON parsing issues, environment variables, pandas DataFrame columns, and unsafe key access patterns.
Fix: Python ModuleNotFoundError even after pip install (venv / virtualenv)
How to fix ModuleNotFoundError in Python when packages are installed but not found inside a virtual environment. Covers venv activation, pip path issues, IDE settings, conda conflicts, and more.
Fix: Python PermissionError: [Errno 13] Permission denied
How to fix Python PermissionError Errno 13 Permission denied when reading, writing, or executing files, covering file permissions, ownership, virtual environments, Windows locks, and SELinux.
Fix: Python RuntimeError: dictionary changed size during iteration
How to fix Python RuntimeError dictionary changed size during iteration caused by modifying a dict while looping over it, with solutions using copies, comprehensions, and safe patterns.
Fix: Python SyntaxError: invalid syntax
How to fix Python SyntaxError invalid syntax caused by missing colons, parentheses, wrong operators, Python 2 vs 3 syntax, f-strings, and walrus operator issues.
Fix: Python TypeError: missing required positional argument
How to fix Python TypeError missing required positional argument caused by missing self, wrong argument count, class instantiation errors, and decorator issues.
Fix: Python TypeError: 'NoneType' object is not subscriptable
Learn why Python raises TypeError NoneType object is not subscriptable and how to fix it with practical solutions for functions, dictionaries, lists, APIs, and regex.
Fix: Python TypeError: takes X positional arguments but Y were given
How to fix Python TypeError takes positional arguments but were given caused by missing self, extra arguments, wrong function calls, and class method confusion.
Fix: Python UnicodeDecodeError – 'utf-8' codec can't decode byte
How to fix Python UnicodeDecodeError 'utf-8' codec can't decode byte in position invalid start byte, covering chardet detection, encoding fallback, BOM handling, pandas CSV encoding, and PYTHONIOENCODING.
Fix: Python ValueError: invalid literal for int() with base 10
How to fix Python ValueError invalid literal for int() with base 10 caused by passing float strings, whitespace, empty strings, or non-numeric characters to int().
Fix: Python ZeroDivisionError: division by zero
Resolve Python's ZeroDivisionError by checking divisors, using try/except, handling empty lists, fixing modulo and Decimal edge cases, and managing numpy/pandas division.
Fix: React TypeError: Cannot read property 'map' of undefined
How to fix React TypeError Cannot read property map of undefined caused by uninitialized state, async data loading, wrong API response structure, and missing default values.
Fix: React Cannot update a component while rendering a different component
How to fix React Cannot update a component while rendering a different component caused by setState during render, context updates in render, and Redux dispatch in render.
Fix: Invalid hook call. Hooks can only be called inside of the body of a function component
How to fix the React Invalid hook call error caused by mismatched React versions, duplicate React copies, calling hooks outside components, and class component usage.
Fix: Objects are not valid as a React child (found: [object Object])
How to fix the React error 'Objects are not valid as a React child' caused by rendering plain objects, Date objects, Promises, or API responses directly in JSX.
Fix: React Hook useEffect has a missing dependency warning
How to fix the React Hook useEffect has a missing dependency warning — covers the exhaustive-deps rule, useCallback, useMemo, refs, proper fetch patterns, and when to safely suppress the lint warning.
Fix: React useState not updating (state not changing after setState)
How to fix React useState not updating. Covers async state updates, functional updates, object mutations, stale closures, setTimeout issues, React 18 batching, props initialization, and debugging state changes.
Fix: Redis OOM command not allowed when used memory > maxmemory
How to fix Redis OOM command not allowed when used memory exceeds maxmemory caused by memory limits, missing eviction policies, large keys, and memory fragmentation.
Fix: Ruby NoMethodError: undefined method for nil:NilClass
How to fix Ruby NoMethodError undefined method for nil NilClass caused by uninitialized variables, missing return values, wrong hash keys, and nil propagation.
Fix: Rust cannot borrow as mutable because it is also borrowed as immutable
How to fix Rust cannot borrow as mutable error caused by aliasing rules, simultaneous references, iterator invalidation, struct method conflicts, and lifetime issues.
Fix: Rust the trait X is not implemented for Y (E0277)
How to fix Rust compiler error E0277 'the trait X is not implemented for Y' with solutions for derive macros, manual trait implementations, Send/Sync bounds, trait objects, and generics.
Fix: Rust lifetime may not live long enough / missing lifetime specifier
How to fix Rust lifetime errors including missing lifetime specifier, may not live long enough, borrowed value does not live long enough, and dangling references.
Fix: Segmentation fault (core dumped) in Linux / C / C++
How to fix the 'Segmentation fault (core dumped)' error in Linux, covering null pointer dereference, buffer overflow, use-after-free, stack overflow, and debugging with GDB, Valgrind, and AddressSanitizer.
Fix: Spring Boot Web server failed to start. Port 8080 was already in use
How to fix the Spring Boot error 'Web server failed to start. Port 8080 was already in use' by killing blocking processes, changing ports, fixing IDE issues, and resolving Docker conflicts.
Fix: Terraform Error: Reference to undeclared resource / unsupported attribute
How to fix Terraform plan errors including reference to undeclared resource, unsupported attribute, undeclared variable, and unknown module output.
Fix: Terraform Error: Resource already exists
How to fix Terraform resource already exists error caused by out-of-band changes, state drift, import issues, duplicate resource blocks, and failed destroys.
Fix: TypeScript Argument of type 'X' is not assignable to parameter of type 'Y' (TS2345)
How to fix TypeScript error TS2345 Argument of type is not assignable to parameter of type, covering null narrowing, union types, generics, callback types, type widening, enums, and React event handlers.
Fix: TypeScript Could not find a declaration file for module (TS7016)
How to fix the TypeScript TS7016 error 'Could not find a declaration file for module' by installing @types packages, creating declaration files, and configuring tsconfig.json.
Fix: TypeScript Property does not exist on type (TS2339)
How to fix TypeScript error TS2339 'Property does not exist on type'. Covers missing interface properties, type narrowing, optional chaining, intersection types, index signatures, type assertions, type guards, window augmentation, and discriminated unions.
Fix: TypeScript Type 'X | undefined' is not assignable to type 'X'
How to fix TypeScript strict null checks error Type X undefined is not assignable caused by optional values, nullable types, missing guards, and strictNullChecks.
Fix: Vite server connection lost / HMR not working
How to fix the '[vite] server connection lost. Polling for restart...' error and HMR not working. Covers file watcher limits, WebSocket config, Docker polling, WSL2, proxy forwarding, SSL issues, firewall blocking, and dependency pre-bundling.
Fix: Error: error:0308010C:digital envelope routines::unsupported
How to fix the Node.js digital envelope routines unsupported error caused by OpenSSL 3.0 changes in Node.js 17+, with solutions for webpack, Vite, React, and Angular.
Fix: Yarn error Integrity check failed / EINTEGRITY sha512
How to fix Yarn integrity check failed and EINTEGRITY sha512 errors caused by corrupted cache, lock file mismatches, registry issues, and network problems.
Fix: Python RecursionError - maximum recursion depth exceeded
Resolve Python's RecursionError by converting recursion to iteration, increasing the recursion limit, fixing infinite loops, and using tail-call optimization patterns.