Re: [PATCH] t7518: fix flaky grep invocation

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 17, 2020, 00:02 UTC
Message-ID: <xmqqr1px90u8.fsf@gitster.c.googlers.com>
In-Reply-To: <pull.884.git.git.1602891594738.gitgitgadget@gmail.com>

"Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes:

Show 7 quoted lines

> output, but on one automatic CI run I observed the following output:
>
> fatal: empty ident name (for <runner@fv-az128-670.gcliasfzo2nullsdbrimjtbyhg.cx.internal.cloudapp.net>) not allowed
>
> Note that 'null' appears as a substring of the domain name, found
> within 'gcliasfzo2nullsdbrimjtbyhg'.  Tighten the test by searching for
> "(null)" rather than "null".

Why do we even need grep again? If we were to segfault, wouldn't test_must_fail catch it for us?

... ahh, OK, your libc may allow NULL left in email and that is what we are trying to catch?

Honestly, I am not sure if it even makes sense to test it like this. The code that the test tries to protect against future breakages roughly look like this these days.

	if (!email) {
		... one way to assign non-NULL to email ...
	}
	if (!email) {
		... do other things to assign non-NULL to email or die ...
	}

	if (want_name) {
		... here we require email to be set because we show
		... it in an error message
	}

The original problem was that the code had "if (want_name)" part first before email==NULL condition has been dealt with, and used email==NULL in one of the error messages. The fix was to move the part that deals with email==NULL up, as it does not need any of the effects that happen in "if (want_name)" block.

Now, what is this particular test protecting against? We may again move the "if (want_name)" block up and trigger the error message in it that uses e-mail while having NULL in email again? If so, would it make more sense to do something along this line, lose the "grep" and keep "test_must_fail"? We expect and require at this point in the code (the patch is inside that "if (want_name)" block) email must have been set up already, so it would be a BUG() otherwise.

Hmm?

 ident.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git i/ident.c w/ident.c
index 6aba4b5cb6..9b71563d95 100644
--- i/ident.c
+++ w/ident.c
@@ -430,6 +430,8 @@ const char *fmt_ident(const char *name, const char *email,
 			if (strict) {
 				if (using_default)
 					ident_env_hint(whose_ident);
+				if (!email)
+					BUG("NULL email when we need to complain???");
 				die(_("empty ident name (for <%s>) not allowed"), email);
 			}
 			pw = xgetpwuid_self(NULL);