Subject: Re: [PATCH 3/3] test-lib.sh: support -x option for shell-tracing

From: Jeff King <[email-masked]>
Date: Fri, 10 Oct 2014 02:21:56 -0400

On Fri, Oct 10, 2014 at 02:13:55AM -0400, Jeff King wrote:

> Having finally figured out how to drop the "set +x" from the output, I
> have noticed that I kind of liked the "test_eval_ret=$?" part of the
> trace (which is now gone, too), because it pretty explicitly tells you
> that the last traced command failed. But now that it has been silenced,
> there's no reason we couldn't add back in our own output to make it more
> clear.

Like:

diff --git a/t/test-lib.sh b/t/test-lib.sh
index a60ec75..81ceb23 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -237,7 +237,11 @@ do
 		shift ;;
 	-x)
 		test_eval_start_='set -x'
-		test_eval_end_='set +x'
+		test_eval_end_='
+			set +x
+			test "$test_eval_ret_" = 0 ||
+			  say_color error >&4 "last command exited with \$?=$?"
+		'
 		verbose=t
 		shift ;;
 	*)
@@ -543,7 +547,7 @@ test_eval_ () {
 	{
 		test_eval_inner_ "$@" </dev/null >&3 2>&4
 		test_eval_ret_=$?
-		$test_eval_end_
+		eval "$test_eval_end_"
 	} 2>/dev/null
 	return $test_eval_ret_
 }

I think we can probably do away with this excessive use of eval, and
just keep a boolean flag for "is -x in effect" and check it inside
test_eval_. Originally I was trying to keep the number of executed
commands down, because everything until the "set +x" ran (including
checks for an "is -x in effect" flag) was shown to the user. But since
that is no longer the case, we can be less stingy with the conditionals.

-Peff