Migrate git operations to go-git library v5.16.4

[Copilot]

Migrates internal/git from shelling out via exec.Command to using the go-git/go-git/v5 library where practical.

Migrated to go-git

• CmdCurrentBranch() - uses repo.Head()
• CmdHasLocalChanges() - uses worktree.Status().IsClean()
• hasRemote() - uses repo.Remotes()
• CmdHasRemoteUnfetchedTags() - uses repo.Tags() for local tag enumeration
• CmdCreateTag() - uses repo.CreateTag()
• CmdRemoveTag() - uses repo.DeleteTag()

Kept as exec.Command

Remote operations remain as shell commands since go-git requires complex auth setup:

• CmdPushTag(), CmdRemoveRemoteTag() - push operations
• CmdGetTag() - for-each-ref with timestamp sorting (no clean go-git equivalent)
• Fetch/log comparison in CmdHasRemoteChanges()/CmdHasUnpushedChanges()

Example

// Before
func CmdCreateTag(tag string) error {
    cmd := exec.Command("git", "tag", tag)
    output, err := cmd.CombinedOutput()
    // ...
}

// After
func CmdCreateTag(tag string) error {
    repo, err := openRepository()
    if err != nil {
        return err
    }
    head, err := repo.Head()
    if err != nil {
        return fmt.Errorf("failed to get HEAD: %w", err)
    }
    _, err = repo.CreateTag(tag, head.Hash(), nil)
    // ...
}

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• dario.cat
  • Triggering command: /update-job-proxy /update-job-proxy (dns block)
• go.googlesource.com
  • Triggering command: /update-job-proxy /update-job-proxy (dns block)
• gopkg.in
  • Triggering command: /update-job-proxy /update-job-proxy (dns block)
• https://api.github.com//advisories
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (http block)
• https://api.github.com/repos/go-git/go-git/releases/latest
  • Triggering command: /usr/bin/curl curl -s REDACTED (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Prepare a plan/implementation to mitigate to latest version of go-git

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[Copilot]

Pull request overview

This PR migrates the codebase from using exec.Command("git", ...) for git operations to using the go-git library (v5.16.4) where practical. The migration improves code maintainability by replacing shell command executions with native Go library calls for several core git operations, while strategically keeping exec.Command for operations that require complex authentication or are simpler with direct command execution.

Key Changes

• Migrated core git operations (CmdCurrentBranch, CmdHasLocalChanges, CmdCreateTag, CmdRemoveTag, hasRemote, CmdHasRemoteUnfetchedTags) to use go-git library functions
• Added go-git v5.16.4 dependency and its transitive dependencies to go.mod
• Retained exec.Command for operations requiring authentication (push/fetch) or specific formatting (tag creation dates)

Reviewed changes

Copilot reviewed 3 out of 747 changed files in this pull request and generated 1 comment.

File	Description
internal/git/git.go	Core migration implementing go-git library for repository operations, with new openRepository() helper and updated functions to use native go-git APIs
internal/git/git_test.go	Formatting improvement splitting multi-line test data for better readability
go.mod	Added go-git v5.16.4 dependency with all required transitive dependencies

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[Copilot]

Slicing head.Hash().String()[:7] will panic if the hash string is shorter than 7 characters. While git hashes are typically 40 characters, add a length check to prevent potential runtime panics in edge cases.

Suggested change

	return head.Hash().String()[:7], nil
	hashStr := head.Hash().String()
	if len(hashStr) >= 7 {
	return hashStr[:7], nil
	}
	return hashStr, nil