Re: precommit hook broken with "git commit <filename>"

[Junio C Hamano <gitster@pobox.com>]

"C. Scott Ananian" <cscott@laptop.org> writes:

> It appears that "git commit <filename>" breaks the git precommit hook.
>  Every other git command updates the index to make the
> commit-about-to-be-made before running the precommit hook, and indeed
> the 'pre-commit.sample' distributed with git assumes that the index
> reflects the commit.  However, in the case of "git commit <filename>"
> the man page states "the commit will ignore changes staged in the
> index, and instead record the current content of the listed files
> (which must already be known to git)".

Doesn't the command call the pre-commit hook with GIT_INDEX_FILE
environment set to the temporary index used to create the (partial)
commit?  The sample pre-commit hook runs "diff --cached" between that
index and HEAD (or the empty tree), and should show the change about to be
committed.