Re: t7405.17 breakage vanishes with GETTEXT_POISON=1

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

SZEDER Gábor <szeder.dev@gmail.com> writes:

> The test in question runs
>
>   test_i18ngrep ! "refusing to lose untracked file at" err
>
> which fails in normal test runs, because 'grep' does find the
> undesired string; that's the known breakage.  Under GETTEXT_POISION,
> however, 'test_i18ngrep' always succeeds because of this condition:
>
>   if test -n "$GETTEXT_POISON"
>   then
>           # pretend success
>           return 0
>   fi
>
> and then in turn the whole test succeeds.

Ah, good spotting.

If a test using "grep" declares that something must not exist in
plumbing message, it writes "! grep something", and because
"test_i18ngrep something" always pretends that something is found
under poisoned build (by the way, would this change when we remove
the separate poisoned build?), "test_i18ngrep ! something" must be
used for Porcelain messages to say the same thing.

Of course, this has a funny interactions with test_expect_failure.
I actually do not think the complexity to work this around is worth
it.  

Changing behaviour of "test_i18ngrep ! something" to always fail
under poisoned build would not work, of course, and changing it to
always fail under poisoned build inside test_expect_failure would
not be a good idea, either, because the know breakage may be at
steps in the same test that is different from the grep, e.g., we may
have a "git dothis" command that should keep the HEAD without
emitting an error message, and we may test it like so:

	git rev-parse HEAD >old &&
	git dothis >out 2>err &&
	test_i18ngrep ! error: err && # no error should be seen
	git rev-parse HEAD >new &&
	test_cmp old new

but currently the command may have a known bug that it moves HEAD;
the command however does not emit an error message.

SO...