Pytest Parametrize Not Generating
Pytest parametrize does not generate cases when ids are misconfigured.
Category archive
Python fixes
Published troubleshooting guides for python issues.
Pytest Coverage Report Incomplete
Pytest coverage reports are incomplete when source paths are wrong.
Pytest Async Test Timeout
Pytest async tests timeout when event loop is not configured.
Pytest Mock Not Working
Pytest mocks fail when patch target is incorrect.
Pytest Fixture Not Tearing Down
Pytest fixtures do not tear down when yield is not used.
Celery Broker Connection Lost
Celery loses broker connection when heartbeat is not configured.
Celery Task Retry Loop
Celery tasks retry infinitely when retry logic is misconfigured.
Celery Result Backend Not Storing
Celery results are not stored when backend URL is invalid.
Celery Beat Schedule Not Running
Celery beat does not run periodic tasks when schedule is misconfigured.
Celery Worker Not Consuming
Celery workers do not consume tasks when queue name is wrong.
FastAPI Response Model Not Matching
FastAPI response models fail when return type does not match schema.
FastAPI Lifespan Context Error
FastAPI lifespan context fails when async generator is not yielded.
FastAPI Security OAuth2 Token Error
FastAPI OAuth2 fails when token URL is misconfigured.
FastAPI Router Not Included
FastAPI routers are not included when app.include_router is not called.
FastAPI Background Task Not Running
FastAPI background tasks fail when added after response is sent.
FastAPI WebSocket Disconnect
FastAPI WebSocket connections drop when accept is not called.
FastAPI CORS Middleware Not Working
FastAPI CORS middleware fails when add_middleware is called wrong.
FastAPI Async Database Session
FastAPI async DB sessions fail when dependency is not awaited.
FastAPI Pydantic Validation Error
FastAPI pydantic validation fails when request body schema is violated.
FastAPI Dependency Injection Failed
FastAPI dependencies fail when Depends is not used correctly.
Django CBV Mixin Lost
Django class-based views lose mixins when method resolution order is wrong.
Django Middleware Not Executing
Django middleware is skipped when not in MIDDLEWARE setting.
Django Signal Not Firing
Django signals do not fire when receiver is not connected.
Django Database Transaction Error
Django transactions fail when atomic block is nested incorrectly.
Django Celery Task Not Running
Django Celery tasks do not run when worker is not started or broker is down.
Django Authentication Backend Not Working
Django auth backends fail when AUTHENTICATION_BACKENDS is misconfigured.
Django Admin Site Not Accessible
Django admin is inaccessible when URL patterns are not included.
Django Static Files Not Serving
Django static files are not served when collectstatic has not run.
Django QuerySet N Plus One
Django N+1 queries occur when select_related or prefetch_related is not used.
Django Migration Apply Failed
Django migrations fail when dependency migration is not applied.
Flask g Object Not Available
Flask g object is not available when accessed outside request context.
Flask CORS Origin Not Allowed
Flask-CORS blocks requests when origins list does not match.
Flask Login User Not Authenticated
Flask-Login does not authenticate when user_loader is not defined.
Flask WTF CSRF Validation Failed
Flask-WTF CSRF validation fails when token is missing or expired.
Flask Session Not Persisting
Flask sessions do not persist when secret_key is not set.
Flask Blueprint URL Not Found
Flask blueprint routes return 404 when url_prefix is wrong.
Flask Jinja Template Error
Flask Jinja templates fail when undefined variable is accessed.
Flask Migrate Upgrade Failed
Flask-Migrate migrations fail when alembic version is inconsistent.
Flask SQLAlchemy Connection Error
Flask SQLAlchemy cannot connect when database URL is invalid.
Flask App Not Starting
Flask applications fail to start when app factory is misconfigured.
Python Encoding Decoding Error
Python encoding errors occur when string is not valid UTF-8.
Python Context Manager Error
Python context managers fail when __exit__ does not handle exceptions.
Python Decorator Not Working
Python decorators do not work when functools.wraps is not used.
Python Async Await Error
Python async/await fails when coroutine is not awaited or event loop is closed.
Python Memory Leak Circular Reference
Python memory leaks occur when circular references prevent garbage collection.
Python GIL Contention Slow
Python threading is slow when GIL contention causes serialization.
Python Requirements Conflict
Python requirements conflict when packages have incompatible dependency versions.
Python Pip Install Permission Denied
Python pip install fails when user lacks write permissions to site-packages.
Python venv Activation Failed
Python virtual environment fails to activate when creation was incomplete.
Python Import Error No Module
Python cannot import module when package is not installed or path is wrong.