Re: [PATCH 2/2] t3404: be resilient against running with the -x flag

From: Jeff King <peff@peff.net>
Date: May 10, 2016, 20:58 UTC
Message-ID: <20160510205800.GC19958@sigill.intra.peff.net>
In-Reply-To: <xmqqshxpofqh.fsf@gitster.mtv.corp.google.com>

On Tue, May 10, 2016 at 12:49:42PM -0700, Junio C Hamano wrote:

Show 5 quoted lines

> I wonder if we can fix "-x" instead so that we do not have to
> butcher tests like this patch does.  It was quite clear what it
> expected to see before this patch, and it is sad that the workaround
> makes less readable (and relies on the real output we are looking
> for never begins with '+').

I don't think there is a scalable, portable way to do so. "-x" output is going to stderr, and is inherited by any functions or subshells. So either we have to ask "-x" output to go somewhere else, or we have to turn it off inside the functions and subshells. The latter requires tweaking each site, which isn't scalable. And there is no way to do the former in a portable way (AFAIK).

That being said, bash supports BASH_XTRACEFD, so maybe something like this:

diff --git a/t/test-lib.sh b/t/test-lib.sh
index 286c5f3..482ec11 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -321,6 +321,7 @@ then
 else
 	exec 4>/dev/null 3>/dev/null
 fi
+BASH_XTRACEFD=4
 
 test_failure=0
 test_count=0

would help Dscho's case (and people on other shells aren't helped, but
they are not hurt either).

-Peff