Re: [PATCH] test-lib-functions: avoid non POSIX ERE in test_dir_is_empty()

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 26, 2021, 19:21 UTC
Message-ID: <xmqqfsuwdnbk.fsf@gitster.g>
In-Reply-To: <CAPUEspjGkHhFNgTe3HnnUvkzwHfKqb9dYO3aCXDh_fRyFMRN6A@mail.gmail.com>

Carlo Arenas <carenas@gmail.com> writes:

> egrep (and also fgrep, which we intentionally support because it is
> missing from some ancient AIX system[1]) will be removed in the
> next[2] release of GNU grep.

It is not a reason not to nudge us to prepare for the eventual removal of these two commands, but we need to keep the facts straight in our log messages.

The way I read [2], they will only start giving a warning message nudging the users to use "grep -[EF]", and for them to be able to warn, I would imagine they have to stay in the release without getting removed.

> [1] 87539416fd (tests: grep portability fixes, 2008-09-30)
> [2] https://git.savannah.gnu.org/cgit/grep.git/commit/?id=a9515624709865d480e3142fd959bccd1c9372d1

There are about 35 places in t/ we call egrep or fgrep; if we can add a pair of replacement shell functions in t/test-lib.sh for them to use whatever command GIT_TEST_EGREP and GIT_TEST_FGREP environment variables specify and fall back on "grep -E/-F" otherwise, we can prepare for the change without too much code churning.

Something along the lines of

	# in test-lib-functions.sh
        : ${GIT_TEST_EGREP:=grep -E} ${GIT_TEST_FGREP:=grep -F}
        egrep () { $GIT_TEST_EGREP "$@" }
        fgrep () { $GIT_TEST_FGREP "$@" }

where people could do something silly like

	GIT_TEST_FGREP='command fgrep' \
	GIT_TEST_EGREP='command egrep' \
	make test

perhaps?