Go Bugfix

TL;DR checklist

• Reproduce or precisely state the wrong behavior.
• Trace from the symptom to the root cause and make a minimal fix.
• Add a regression check and run focused package tests.

Key read-only checks

• Inspect the failing output, call path, and nearby tests before editing.

Common pitfalls

• Do not patch only the downstream panic when the bad value originates earlier.

Agent procedure

Follow the Workflow, Safety rules, and Quality checklist below.

Quick references

• Workflow below.

Last verified: unverified

When to use

Use when a Go program has a specific, identifiable bug (wrong output, panic, failing test, deadlock) that needs a fix.

Goal

Fix the actual bug with a minimal, correct change, backed by a regression test — without refactoring unrelated code.

Workflow

1. Reproduce or precisely understand the failing behavior: run the failing test, reproduce the panic, or get the exact wrong output from the user.
2. Inspect existing tests around the affected code to understand intended behavior and existing coverage.
3. Trace the code path to find the root cause (not just where the symptom surfaces — e.g. a nil pointer panic three calls downstream from where a value was never initialized).
4. Implement the minimal fix at the root cause.
5. Add a regression test that fails before the fix and passes after it.
6. Run the focused test(s) (go test -run <TestName> ./...) to confirm, then run the broader package tests to check for regressions.

Safety rules

• Do not refactor unrelated code, rename things, or "clean up while you're in there" — fix only the bug.
• Do not silently swallow the error the bug caused (recover() without acting on it, ignoring an error return) — fix the cause, not the symptom.
• If the root cause is unclear after investigation, say so rather than applying a fix that only masks the symptom.

Output format

## Bug
<what's wrong, how it manifests>

## Root cause
<file:line, why it happens>

## Fix
<the diff/change, minimal and scoped to the bug>

## Regression test
<the test added, and confirmation it failed before / passes after>

## Test run result

Quality checklist

• The fix addresses the root cause, not just where the symptom appeared
• A regression test was added and shown to fail before the fix
• No unrelated code was refactored or renamed
• Focused tests were run and pass after the fix
• Errors are handled, not silently discarded