git diff/log --check exitcode and PAGER environment variable

Using my default PAGER=less, git log --check exits with exit code 0, contrary to documentation.

There is this old thread: "[PATCH 1/5] "diff --check" should affect exit status" http://thread.gmane.org/gmane.comp.version-control.git/68145/focus=68148 which seemed not to reach a conclusion.

For git log, I still have not been able to make it exit with anything other than 0 - contrary to documentation.

May I propose a change to either documentation or behavior of "git diff --check". The current one has:

--check::
	Warn if changes introduce trailing whitespace
	or an indent that uses a space before a tab. Exits with
	non-zero status if problems are found. Not compatible with
	--exit-code.

This, clearly, is not correct:

$ PAGER=less git diff --check (my default PAGER) or $ unset PAGER ; git diff --check always exits with exit code 0. But

$ git --no-pager diff --check or $ PAGER=cat git diff --check or $ PAGER= git diff --check exits with exit code 2 on error (curiously PAGER= and unset PAGER give different results)

But the --exit-code overrides any of that:

$ git --no-pager diff --check --exit-code exits with exit code 3 on error (with or without the --no-pager).

I'm not sure about a good rephrasing. How about: '... "git diff" exits with non-zero status if problems are found and run with --exit-code.'

While this documentation string is found in diff-options.txt and included in:

git-diff-files.txt git-diff-index.txt git-diff-tree.txt git-diff.txt git-format-patch.txt git-log.txt

At least for the git-log cases, the behavior is not the same as for git-diff:

$ PAGER=cat git --no-pager log HEAD~20..HEAD --check --exit-code $ echo $? 0 Though there are several check failures (red squares in output), it exits with 0, even when using all the tricks that work with "git diff".

Clearly here, the documentation is "even more wrong". Hence the explicit mention of "git diff" in the help string for the --check option.

What do you think?

Peter