Git hooks for metadata storage/retrieval

Question

One of git's unavoidable quirks is its inability to store and retrieve metadata about a file. For example, on the mac, labels are stored with "extended attributes" (accessible with xattr), and any checkout/reset/merge/pull command will erase those attributes if the file is affected by the checkout.

I've looked around to see if someone has written metadata-saving scripts already, but I came up dry.

So what I'd like to do is use Git's hook system to:

1. Read extended attributes when files are committed,
2. Write the attributes to a file stored in the repository that also gets committed,
3. Apply the extended attributes to files that are modified in a merge/checkout/reset.

Which of the hooks should I use? Are post-receive and pre-commit all that I need? Can pre-commit also add a file to the commit (i.e., after writing the new attributes)?

Answer 1

The gibak tool uses pre-commit and post-checkout to let its ometastore tool save/restore metadata (optionally including xattrs).

You do not want post-receive. It is run on the remote end of pushes. It runs for bare repositories, so it has no business trying to update any files from the contents of a pushed commit. Do it in post-checkout where you know you will have a working tree available.