Git Plugin: Detached HEAD Prompt Display in Oh‑My‑Zsh 4.7.0

Handling Detached HEAD in the Git Prompt

In Oh-My-Zsh 4.7.0, the git_prompt_info function is designed to prioritize the current branch name. When the repository enters a detached HEAD state, the function fails to find a symbolic reference and automatically falls back to displaying the abbreviated commit hash (short SHA). There is no built-in boolean toggle to switch between the hash and a custom label; the behavior is determined by whether a symbolic ref exists.

Customizing the Detached Display

To override the default short SHA with a custom string or label, you must define the ZSH_THEME_GIT_PROMPT_DETACHED variable in your configuration. This allows you to maintain a consistent visual style even when not on a named branch.

1. Open your ~/.zshrc file.
2. Add the following line before the line that sources oh-my-zsh.sh:

   ZSH_THEME_GIT_PROMPT_DETACHED="(detached: %s)"

3. Reload your configuration:

   source ~/.zshrc

Technical Explanation and Assumptions

The plugin's logic relies on git symbolic-ref HEAD. If this command returns a non-zero exit code (which occurs during a detached HEAD), the plugin executes git rev-parse --short HEAD to retrieve the commit hash.

Assumptions: This behavior assumes you are using a theme that calls the git_prompt_info function. If you are using a highly customized theme that bypasses this function, the ZSH_THEME_GIT_PROMPT_DETACHED variable will have no effect. We assume the use of Git 2.x or newer where rev-parse --short is standard.

Verification Steps

To verify the prompt is responding correctly to the detached state, run the following commands in a test repository:

• Enter detached state: git checkout $(git rev-list --max-parents=0 HEAD) (checks out the initial commit).
• Verify manually: Run git symbolic-ref HEAD; it should return a fatal error, confirming the state.
• Check prompt: Observe if the prompt displays the short SHA or your custom ZSH_THEME_GIT_PROMPT_DETACHED string.

Diagnostic Note: If the prompt does not change after these steps, please specify which Zsh theme you are currently using, as some themes override the default git plugin functions.