feat: auto-change directory after setup command

[liamawhite]

Add automatic directory change to newly created repository after successful setup, making the setup command consistent with other worktree commands (add, switch, remove) that also change directories.

Resolves #6

Generated with Claude Code

[claude]

Claude finished @liamawhite's task —— View job

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PR Review: Auto-change directory after setup command

Review Checklist:

• Read and analyze the changed file (cmd/setup.go)
• Check consistency with other commands that change directories
• Review for code quality and best practices
• Identify potential bugs or issues
• Assess performance considerations
• Check for security concerns
• Evaluate test coverage needs
• Provide comprehensive feedback

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Review Feedback

✅ Code Quality & Best Practices

The implementation follows the established pattern used by other commands (add, switch, remove, clear). The use of fmt.Fprintf(os.Stderr, "WT_CHDIR:%s\n", ...) is consistent with the codebase's directory change mechanism.

✅ Consistency

Excellent consistency with other commands:

• add: Changes to filepath.Join(wm.GitRoot, branch) (the new worktree)
• switch: Changes to selectedWorktree (the target worktree)
• remove: Changes to wm.GitRoot (back to main repo)
• clear: Changes to wm.GitRoot (back to main repo)
• setup: Changes to config.RepoName (the newly created repo) ✅

⚠️ Potential Issues

1. Directory Path Accuracy: The change uses config.RepoName which contains just the repository name (e.g., "worktree" from "liamawhite/worktree"). However, looking at the setup code in pkg/setup/setup.go:84-90, I can see that:

   if err := os.MkdirAll(repoConfig.RepoName, 0755); err != nil {
       return err
   }
   if err := os.Chdir(repoConfig.RepoName); err != nil {
       return err
   }

   The setup process creates and changes into this directory, so using config.RepoName is correct.

2. Error Handling: The directory change happens after SetupRepository() succeeds, which is appropriate. If setup fails, no directory change is attempted.

✅ Performance Considerations

No performance impact - this is a simple string output to stderr.

✅ Security Considerations

No security concerns:

• Uses the same RepoName that was already validated during parsing
• No user input injection risk in the WT_CHDIR output
• Follows established patterns

⚠️ Test Coverage

Gap identified: While there are integration tests for the setup command (integration/integration_test.go:47), there are no tests that verify:

1. The WT_CHDIR output is generated
2. The correct directory path is output
3. Directory change behavior matches other commands

Recommendation: Consider adding a test case to verify the WT_CHDIR output, similar to:

func TestSetupDirectoryChange(t *testing.T) {
    // Capture stderr and verify WT_CHDIR output contains expected directory
}

📍 Code Location Reference

The change is in cmd/setup.go:45 and follows the exact pattern used in:

• cmd/add.go:46
• cmd/switch.go:78
• cmd/remove.go:89
• cmd/clear.go:52

Overall Assessment

✅ APPROVED - This is a well-implemented change that:

• Solves the stated problem (makes setup consistent with other commands)
• Follows established patterns perfectly
• Has no significant risks or issues
• Improves user experience by eliminating manual cd after setup

The only minor improvement would be adding test coverage for the WT_CHDIR behavior, but this is not a blocker for merging.

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