[PATCH v2] test-lib: fix GIT_TEST_SANITIZE_LEAK_LOG

["Rubén Justo" <rjusto@gmail.com>]

In the if-elses chain we have in "check_test_results_san_file_", we
consider three variables: $passes_sanitize_leak, $sanitize_leak_check
and lastly, implicitly, GIT_TEST_SANITIZE_LEAK_LOG (always set to "true"
at that point).

For the first two variables we have different considerations depending
on the value of $test_failure, which make sense.  However, for the
third, GIT_TEST_SANITIZE_LEAK_LOG, we don't;  regardless of
$test_failure, we use "invert_exit_code=t" to produce a non-zero
return value.

That assumes "$test_failure = 0" is always true at that point.  But it
is not:

   $ git checkout v2.40.1
   $ make SANITIZE=leak
   $ make -C t GIT_TEST_SANITIZE_LEAK_LOG=true t3200-branch.sh
   ...
   With GIT_TEST_SANITIZE_LEAK_LOG=true, our logs revealed a memory leak, exiting with a non-zero status!
   # Simulated failures as TODO & now exiting with 0 due to --invert-exit-code

We need to use "invert_exit_code=t" only when "$test_failure = 0".

Probably we have missed this because GIT_TEST_SANITIZE_LEAK_LOG is
commonly used in combination with GIT_TEST_PASSING_SANITIZE_LEAK=check,
the second variable noted above, for which we have, as already said,
different considerations depending on the value of $test_failure.

However GIT_TEST_SANITIZE_LEAK_LOG has value used on its own, as it was
documented in faececa53f (test-lib: have the "check" mode for
SANITIZE=leak consider leak logs, 2022-07-28).

Let's add the missing conditions in the if-elses chain to make it work
as expected.

Note that we're not resetting the value of "invert_exit_code" when
$test_failure is non-zero.  Doing that is only needed when
GIT_TEST_PASSING_SANITIZE_LEAK=check, the second variable noted above.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Rubén Justo <rjusto@gmail.com>
---

Changes since v1:
- dropped 1/1 as it was erroneously included
- reworded the message to better capture the situation and the goal
- show a message also when $test_failure is non-zero


It is probably worth revisiting the use of "invert_exit_code=t"
in this SANITIZE_LEAK machinery.  But I'll stop here.

---
 t/test-lib.sh | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/t/test-lib.sh b/t/test-lib.sh
index 5ea5d1d62a..945ede50ac 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -1264,9 +1264,12 @@ check_test_results_san_file_ () {
 	then
 		say "As TEST_PASSES_SANITIZE_LEAK=true isn't set the above leak is 'ok' with GIT_TEST_PASSING_SANITIZE_LEAK=check" &&
 		invert_exit_code=t
-	else
+	elif test "$test_failure" = 0
+	then
 		say "With GIT_TEST_SANITIZE_LEAK_LOG=true our logs revealed a memory leak, exit non-zero!" &&
 		invert_exit_code=t
+	else
+		say "With GIT_TEST_SANITIZE_LEAK_LOG=true our logs revealed a memory leak..."
 	fi
 }
 
-- 
2.34.1