Trace And Isolate
Applies systematic tracing and isolation techniques to pinpoint exactly where a bug...
Install
npx skills add rohitg00/skillkit --skill trace-and-isolate -g -a claude-code -y- Repository
- rohitg00/skillkit1.6k
- Category
- Testing
- Updated
- 5mo ago
- License
- Apache-2.0
- Context cost
- Mediumabout 1,587 tokens
- Runs scripts
- No, instructions only
What it does
Applies systematic tracing and isolation techniques to pinpoint exactly where a bug originates in code. Use when a bug is hard to locate, code is not working as expected, an error or crash appears with unclear cause, a regression was introduced between recent commits, or you need to narrow down which component, function, or line is faulty. Covers binary search debugging, git bisect for regressions, strategic logging with [TRACE] patterns, data and control flow tracing, component isolation, minimal reproduction cases, conditional breakpoints, and watch expressions across TypeScript, SQL, and bash.
Trace and Isolate
You are using systematic tracing and isolation techniques to narrow down where a bug originates. The goal is to find the exact location in code where behavior diverges from expectation.
Quick Reference
| Scenario | Technique |
|---|---|
| Large codebase / complex flow | Binary search debugging |
| Bug appeared between commits | git bisect |
| Unclear data transformation | Strategic [TRACE] logging |
| Which component is faulty? | Component isolation + mocks |
| Bug hard to reproduce | Minimal reproduction case |
| Conditional or intermittent bug | Conditional breakpoints / watch expressions |
Binary Search Debugging
When you have a large codebase or complex flow:
- Identify the start - Last known good state
- Identify the end - First observed bad state
- Test the middle - Check if behavior is good or bad
- Repeat - Binary search on the half with the bug
Code Path Binary Search
Start: User clicks submit button
End: Error shown to user
Midpoint 1: Form validation
→ Data looks correct here? Continue to later code
→ Data already wrong? Focus on earlier code
Midpoint 2: API request construction
→ Request payload correct? Focus on server side
→ Payload already malformed? Focus on form handling
...Continue until exact line is found
Git Bisect for Regressions
When a bug appeared between two commits:
# Start bisect
git bisect start
# Mark current (broken) state as bad
git bisect bad
# Mark last known good state
git bisect good v2.3.0
# Git checks out middle commit, test and mark
git bisect good # or git bisect bad
# Repeat until found
# Git will report: "abc123 is the first bad commit"
# Clean up
git bisect reset
Automated bisect with test script:
git bisect start HEAD v2.3.0
git bisect run npm test -- --grep "failing test"
Tracing Techniques
Strategic Logging
Add temporary logging at key points:
