common-failure-patterns

name	common-failure-patterns
description	Common failure patterns organized by category with symptoms, causes, and fixes. Activate when: diagnosing dependency conflicts, environment issues, PATH problems, permission errors, CORS errors, DNS failures, timeout issues, async bugs, concurrency problems, race conditions, memory leaks, deadlocks.

Common Failure Patterns

Dependency Conflicts

Version Mismatch

Symptoms:
- ImportError or ModuleNotFoundError at runtime
- "No matching distribution found" during install
- Tests pass locally but fail in CI
- AttributeError on functions that "should exist"

Diagnosis:
  pip freeze | grep <package>    # What's actually installed?
  pip show <package>             # Version + dependencies
  pip check                      # Dependency compatibility check
  npm ls <package>               # Node dependency tree
  npm ls --all 2>&1 | grep ERR   # Find conflicts

Common causes:
- Lock file not committed (pip.lock, yarn.lock, package-lock.json)
- Different Python/Node version between local and CI
- Transitive dependency updated with breaking change
- Multiple packages requiring conflicting versions

Fixes:
- Pin exact versions in requirements.txt / package.json
- Use lock files and commit them to version control
- Use virtual environments to isolate project dependencies
- Run pip install --upgrade --force-reinstall 
 For Node: delete node