On 4/11/2023 5:20 PM, Jim Porter wrote:
> If we did something like this, I think both post-commit and pre-push 
> hooks would be useful. The former gives committers immediate feedback on 
> their commit message (if they read the output), while the latter is what 
> ensures that the upstream commit messages are properly-formatted.

Attached is a mostly-working pair of hooks (post-commit and pre-push) to 
check this. There's still a bit more work to do though:

  1. Clean up the output a bit
  2. Make it work on non-gawk awks

Both of those should be pretty easy though. Here's an example of the 
error if you try to push:

--------------------------------------------------

   In commit 89f2dbb773: My commit message
     File lisp/bad.el listed in commit message, but not in diff
   Push aborted; please see the file 'CONTRIBUTE'
   error: failed to push some refs to 
'jporter@git.sv.gnu.org:/srv/git/emacs.git'

--------------------------------------------------

For the post-commit hook, we just pass the current commit SHA to our awk 
script, which checks that SHA to make sure its commit message is 
correct. For the pre-push hook, we need to compare the local ref that 
we're pushing to the remote ref, and then check every commit between the 
two (the Git documentation explains a bit about how the hook works[1]).

Assuming the general strategy looks ok, I'll finish this up and add more 
documentation for what's going on.

[1] https://git-scm.com/docs/githooks#_pre_push