common-bug-patterns

Prompt file imported from PauloHYBEX/Nexus-TCMS (.windsurf/workflows/references/common-bug-patterns.md). Copyright stays with the author.

<common_bug_patterns>

Patterns for detecting common bugs in AI-generated code. Used by the verifier agent and verify-work workflow to catch issues that pass basic existence checks but fail in practice.

Stub Detection

These patterns indicate placeholder code regardless of file type:

Comment-based stubs

grep -E "(TODO|FIXME|XXX|HACK|PLACEHOLDER)" "$file"
grep -E "implement|add later|coming soon|will be" "$file" -i
grep -E "// \.\.\.|/\* \.\.\. \*/|# \.\.\." "$file"

Placeholder text in output

grep -E "placeholder|lorem ipsum|coming soon|under construction" "$file" -i
grep -E "sample|example|test data|dummy" "$file" -i

Empty or trivial implementations

grep -E "return null|return undefined|return \{\}|return \[\]" "$file"
grep -E "pass$|\.\.\.|\bnothing\b" "$file"
grep -E "console\.(log|warn|error).*only" "$file"

Hardcoded values where dynamic expected

grep -E "id.*=.*['\"].*['\"]" "$file"
grep -E "count.*=.*\d+|length.*=.*\d+" "$file"

Wiring Gaps

Code exists but isn't connected to the rest of the system:

Unregistered routes

• Route handler file exists but not imported in the router/app entry
• API endpoint defined but not added to the route table

Unused exports

• Component exported but never imported anywhere
• Utility function exported but no consumers

Missing environment variables

• Code references process.env.X but .env.example doesn't list it
• Config reads a key that's not in the defaults

Broken imports

• Import path doesn't match actual file location (case sensitivity on Linux)
• Circular dependency that works in dev but fails in production build

State Drift

State management issues that cause subtle bugs:

Stale state references

• React component reads state that was updated in a different render cycle
• Cache not invalidated after mutation

Race conditions

• Multiple async operations writing to the same resource
• Optimistic UI update without rollback on failure

Schema mismatch

• Database migration changes column type but API response type not updated
• Frontend expects field that backend stopped sending

Verification Levels

For each artifact, verify at the appropriate level:

Levels 1-3 can be checked programmatically. Level 4 often requires human verification (verify-work UAT).

</common_bug_patterns>