Re: [PATCH] test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFD

From: Jeff King <peff@peff.net>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: "SZEDER Gábor" <szeder.dev@gmail.com>,
	git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
	"Derrick Stolee" <derrickstolee@github.com>,
	"Taylor Blau" <me@ttaylorr.com>
Subject: Re: [PATCH] test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFD
Date: Wed, 1 Dec 2021 14:38:08 -0500	[thread overview]
Message-ID: <YafPIOD2bmeYrPR2@coredump.intra.peff.net> (raw)
In-Reply-To: <211201.868rx4beer.gmgdl@evledraar.gmail.com>

On Wed, Dec 01, 2021 at 03:06:44PM +0100, Ævar Arnfjörð Bjarmason wrote:

> I don't really mind keeping BASH_XTRACEFD if it's doing something
> useful, but I feel like I'm missing something here. Is it really doing
> something useful?
> 
> AFAICT the ony case where it mattered was t1510-repo-setup.sh, which
> with my upthread
> <patch-1.1-9f735bd0d49-20211129T200950Z-avarab@gmail.com> now works with
> -x, at the trivial cost of skipping a small bi of the test with -x.
> 
> I suppose we could move this BASH_XTRACEFD to tht file in particular if
> anyone feel strongly about the trivial loss of tracing that entails. I
> figured just skipping it under "-x" and adding a "say" to that effect
> was a better trade-off.
> 
> For the rest of the test suite BASH_XTRACEFD effectively didn't matter,
> since all our tests had to work under --verbose-log -x anyway under
> dash.
> 
> Am I just wrong about this line of thinking, or is it purely that you
> two would like to keep BASH_XTRACEFD in case some hypothetical future
> caller wants to make use of "test_untraceable=UnfortunatelyYes" again?

I don't know that I'd call it purely hypothetical. It was the state for
many years in the past. And there has to be per-test hackery to keep it
that way. So I wouldn't call XTRACEFD a workaround at all; in my mind it
was the solution.

Now if people want to do that per-test hackery _also_, because it keeps
"-x" more useful for folks who can't or won't use bash, I have no
problem with that. What I was hoping to avoid was making it a
hard requirement, because now it's one more subtle thing for test
writers to have to remember and deal with.

But maybe that ship is sailed. If we are running with "-x" and dash in
CI, then they're going to see confusing failures there regardless.

-Peff