fix

name	fix
description	Fix a bug following the test-first approach -- reproduce with test, then fix, then verify
disable-model-invocation	true
user-invocable	true
allowed-tools	Bash, Read, Write, Edit, Grep, Glob, Agent, TodoWrite

Bug Fix -- Test-First Approach

Fix a bug by first reproducing it with a failing test, then fixing the code, then verifying.

Arguments

• $ARGUMENTS -- description of the bug (e.g., "margin collapse not working for empty divs", "PNG transparency renders as black", "CSS shorthand font not parsing correctly")

Workflow

Step 1: Reproduce

1. Understand the bug -- read the description, search for related issues:

   gh issue list --search "$ARGUMENTS"
   

2. Write a failing test that demonstrates the bug:

   • Name it: BugFix_Description_ShouldBehavior
   • The test MUST fail before your fix (proves the bug exists)
   • Keep the test minimal -- smallest HTML/CSS that reproduces the issue

3. Run the test -- confirm it FAILS:

   dotnet test --configuration Release --filter "FullyQualifiedName~BugFix_Description"
   

   If it passes, the test doesn't reproduce the bug. Try again.

Step 2: Fix

4. Fix the bug -- make the minimal change needed:

   • Don't refactor unrelated code
   • Don't "improve" surrounding code
   • Just fix the bug

5. Run the failing test -- confirm it PASSES:

   dotnet test --configuration Release --filter "FullyQualifiedName~BugFix_Description"
   

Step 3: Verify

6. Run ALL tests -- make sure the fix didn't break anything:

   dotnet test --configuration Release
   

7. If the fix touches a hot path, run performance check:

   cd benchmarks/EggPdf.Benchmarks && dotnet run -c Release -- --filter *{Scenario}* --job short
   

Step 4: Commit

8. Commit with fix: prefix:

   git add -A && git commit -m "fix: description of what was wrong and why"
   

Key Rules

• ALWAYS write the failing test FIRST. No test = no fix.
• NEVER commit a fix without a regression test.
• Keep the fix minimal. One bug per commit.