How to ignore gitignore

Overview

In Git, the `.gitignore` file is used to specify intentionally untracked files that Git should ignore. This is incredibly useful for preventing temporary files, build artifacts, log files, or sensitive configuration details from being committed to your repository. However, there are specific scenarios where you might need to override this behavior, either to temporarily stop tracking a file that's usually tracked, or to force Git to track a file that is currently being ignored.

This article will guide you through the methods to effectively 'ignore' or 'unignore' files in Git, focusing on how to manage files that fall outside the standard `.gitignore` rules or when you need a temporary bypass.

Understanding Git's Ignore Mechanisms

Git has several ways of ignoring files:

• `.gitignore` files: These are configuration files placed in your repository that specify patterns of files to ignore. They are version-controlled and shared with collaborators.
• `.git/info/exclude` file: This file works similarly to `.gitignore` but is local to your repository and not committed. It's useful for personal ignores.
• Global Gitignore: You can configure a global ignore file for your user account, which applies to all your Git repositories.

While these mechanisms are designed to keep your repository clean, sometimes you need finer-grained control for individual files.

Temporarily Ignoring Tracked Files

Sometimes, you might have a file that is already tracked by Git (meaning it's in the repository) but you want Git to stop checking it for changes. This is common for configuration files that might have local, sensitive changes you don't want to commit. The most effective way to achieve this is using the git update-index --assume-unchanged command.

Using git update-index --assume-unchanged

This command tells Git to effectively 'forget' about changes to a specific file. Git will stop staging modifications and won't show it as modified in git status. It's important to understand that this flag is a local setting and is not committed to the repository. It only affects your local working copy.

How to use it:

1. Ensure the file is currently tracked by Git.
2. Run the command: git update-index --assume-unchanged path/to/your/file.txt

After running this command, Git will stop monitoring that file for changes. If you later want Git to start tracking changes again, you need to explicitly tell it to do so:

How to revert:

1. Run the command: git update-index --no-assume-unchanged path/to/your/file.txt

Caveats:

• If the file is modified on the remote repository and you pull changes, Git might overwrite your local changes or cause conflicts, as it assumes your local version is not changing.
• This command can be confusing if you forget you've applied it. Use git ls-files --exclude-standard --others --ignored --cached or git status --ignored to see ignored files, and git ls-files --stage to see files staged or tracked. To specifically see files marked with assume-unchanged, you can use git update-index --show-index which might show `i` for assume-unchanged.

Forcing Git to Track Ignored Files

Conversely, you might have a file that is listed in your `.gitignore` file, but for a specific reason, you want to track it in your local repository. This is less common but can be necessary for certain development workflows.

Using git update-index --no-skip-worktree

This command is used to force Git to track a file that is currently being ignored. It essentially tells Git to disregard the ignore rules for this specific file and ensure it's considered part of the repository.

How to use it:

1. Ensure the file is listed in a `.gitignore` file or matches an ignore pattern.
2. Run the command: git update-index --no-skip-worktree path/to/your/file.txt

This command also applies locally and is not committed. It makes Git aware of the file and its potential changes.

How to revert:

1. To stop tracking it again and have Git ignore it based on `.gitignore`, you would use: git update-index --skip-worktree path/to/your/file.txt

Note: The --skip-worktree and --no-skip-worktree flags are primarily used in scenarios where you have local modifications to files that are otherwise ignored, and you want Git to be aware of these local modifications without necessarily committing them. This is often used in conjunction with build systems or specific deployment workflows.

Best Practices and Considerations

• Understand the Scope: Remember that git update-index commands are local to your repository. They are not shared with collaborators.
• Document Your Actions: If you're using these commands for specific reasons, consider adding a comment in a team README or a local documentation file explaining why certain files are being managed this way.
• Avoid Overuse: These commands are powerful but can lead to confusion if overused or forgotten. They are best reserved for specific, well-understood situations.
• Use `.gitignore` Appropriately: For most use cases, ensuring your `.gitignore` file is comprehensive and correctly configured is the best approach.

By understanding and judiciously applying these commands, you can gain more control over how Git manages your files, ensuring a smoother development workflow.