Legacy error-resolution reference archive retained for migration. Do not route user tasks here; use systematic-debugging for active bug, stack-trace, and root-cause work.
Legacy reference archive for first-principle error diagnosis across languages and frameworks.
This directory is retained because it contains substantial analysis, pattern, and replay material. It is not an active code-quality route owner. Route user-facing bug, stack-trace, and root-cause tasks to systematic-debugging.
The 5-step Error Resolution Process:
1. CLASSIFY -> 2. PARSE -> 3. MATCH -> 4. ANALYZE -> 5. RESOLVE
| | | | |
What type? Extract key Known Root cause Fix +
information pattern? analysis PreventWhen you encounter an error:
| Category | Indicators | Common Causes |
|---|---|---|
| Syntax | Parse error, Unexpected token | Typos, missing brackets, invalid syntax |
| Type | TypeError, type mismatch | Wrong data type, null/undefined access |
| Reference | ReferenceError, NameError | Undefined variable, scope issues |
| Runtime | RuntimeError, Exception | Logic errors, invalid operations |
| Network | ECONNREFUSED, timeout, 4xx/5xx | Connection issues, wrong URL, server down |
| Permission | EACCES, PermissionError | File/directory access, sudo needed |
| Dependency | ModuleNotFound, Cannot find module | Missing package, version mismatch |
| Configuration | Config error, env missing | Wrong settings, missing env vars |
| Database | Connection refused, query error | DB down, wrong credentials, bad query |
| Memory | OOM, heap out of memory | Memory leak, large data processing |
Identify the error category by examining:
ENOENT, TypeError)Extract key information:
- Error code: [specific code if any]
- File path: [where the error originated]
- Line number: [exact line if available]
- Function/method: [context of the error]
- Variable/value: [what was involved]
- Stack trace depth: [how deep is the call stack]Check against known error patterns:
patterns/ directory for language-specific patternsApply the 5 Whys technique:
Error: Cannot read property 'name' of undefined
Why 1? -> user object is undefined
Why 2? -> API call returned null
Why 3? -> User ID doesn't exist in database
Why 4? -> ID was from stale cache
Why 5? -> Cache invalidation not implemented
Root Cause: Missing cache invalidation logicGenerate actionable solution:
When resolving an error, provide:
## Error Diagnosis
**Classification**: [Category] / [Severity] / [Scope]
**Error Signature**:
- Code: [error code]
- Type: [error type]
- Location: [file:line]
## Root Cause
[Explanation of why this error occurred]
**Contributing Factors**:
1. [Factor 1]
2. [Factor 2]
## Solution
### Immediate Fix
[Quick steps to resolve]
### Code Change
[Specific code to add/modify]
### Verification
[How to verify the fix works]
## Prevention
[How to prevent this error in the future]
## Replay Tag
[Unique identifier for this solution - for future reference]The replay system records successful solutions for future reference.
After resolving an error, record it:
# Create solution record in project
mkdir -p .claude/error-solutions
# Solution file format: [error-type]-[hash].yaml# .claude/error-solutions/[error-signature].yaml
id: "nodejs-module-not-found-express"
created: "2024-01-15T10:30:00Z"
updated: "2024-01-20T14:22:00Z"
error:
type: "dependency"
category: "ModuleNotFound"
language: "nodejs"
pattern: "Cannot find module 'express'"
context: "npm project, missing dependency"
diagnosis:
root_cause: "Package not installed or node_modules corrupted"
factors:
- "Missing npm install after git clone"
- "Corrupted node_modules directory"
- "Package not in package.json"
solution:
immediate:
- "Run: npm install express"
proper:
- "Check package.json has express listed"
- "Run: rm -rf node_modules && npm install"
code_change: null
verification:
- "Run the application again"
- "Check express is in node_modules"
prevention:
- "Add npm install to project setup docs"
- "Use npm ci in CI/CD pipelines"
metadata:
occurrences: 5
last_resolved: "2024-01-20T14:22:00Z"
success_rate: 1.0
tags: ["nodejs", "npm", "dependency"]When encountering an error:
.claude/error-solutions/ for matching patternssignature = hash(
error_type +
error_code +
normalized_message + # remove specific values
language +
framework
)Example transformations:
Cannot find module 'express' -> Cannot find module '{module}'TypeError: Cannot read property 'name' of undefined -> TypeError: Cannot read property '{prop}' of undefinedUseful commands during debugging:
# Verbose error output
NODE_DEBUG=* node app.js
# Memory debugging
node --inspect app.js
# Check installed packages
npm ls [package-name]
# Verify package.json
npm ls --depth=0# Debug mode
python -m pdb script.py
# Check installed packages
pip show [package-name]
pip list# Check file permissions
ls -la [file]
# Check port usage
lsof -i :[port]
netstat -an | grep [port]
# Check environment variables
env | grep [VAR_NAME]
printenv [VAR_NAME]
# Check disk space
df -h
# Check memory
free -m # Linux
vm_stat # macOSWhen the error location is unclear:
Create the smallest code that reproduces the error:
Explain the problem out loud (or to Claude):
Find which commit introduced the bug:
git bisect start
git bisect bad # current commit is bad
git bisect good [last-known-good-commit]
# Git will checkout commits for you to test
git bisect good/bad # mark each as good or bad
git bisect reset # when donepatterns/ - Language-specific error patterns
nodejs.md - Node.js common errorspython.md - Python common errorsreact.md - React/Next.js errorsdatabase.md - Database errorsdocker.md - Docker/container errorsgit.md - Git errorsnetwork.md - Network/API errorsanalysis/ - Analysis methodologies
stack-trace.md - Stack trace parsing guideroot-cause.md - Root cause analysis techniquesreplay/ - Replay system
solution-template.yaml - Template for recording solutionsf627ab5
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