Another problem you might not have run into yet: the names given by
rev-list are not quoted in any way, and will just omit newlines. So if
your hook is trying to avoid malicious garbage like "foo\nbar", it won't
work.

Thanks for that warning. I was not aware that rev-list didn't quote file names.

Those names are really just intended as hints for pack-objects. I
suspect the documentation could be more clear about these limitations.

That would indeed be great and would have likely prevented the obvious
misconceptions on my side.

I'm not sure what you mean by "one by one", since that is inherently
what rev-list is doing under the hood. If you mean "running a separate
process for each commit", then yes, that will be slow.

Yes, that's what I meant to say.

But if you want
to know all of the names touched in a set of commits, I have used
something like this before:

  git rev-list $new --not --all |
  git diff-tree --stdin --format= -r -c --name-only

Thanks, that looks promising and solves at least one of my use cases. The only
minor problem is that there seems to be no way to pipe the diff-tree output to
cat-file without massaging it with awk first.

I have three uses cases in my pre-receive hooks:

1. Filters solely based on the file name
   ? your suggestions works perfectly here
2. Filters based only on file contents
   ? git rev-list --objects + git cat-file provide everything I need
3. One filter based on file size and name (forbid large files, with exceptions)
   ? I'm guessing "git rev-list | git diff-tree --stdin | awk |
     git cat-file --batch-check" is the best solution to extract the necessary
     information from git in this case?

-- Moritz