[PATCH 5/5] test-lib-functions: detect test_when_finished in subshell

From: John Keeping <john@keeping.me.uk>
Date: Sep 5, 2015, 13:12 UTC
Message-ID: <59a8583f79c5ac4661f140262e01cd602286f740.1441458341.git.john@keeping.me.uk>
In-Reply-To: <cover.1441458341.git.john@keeping.me.uk>

test_when_finished does nothing in a subshell because the change to test_cleanup does not affect the parent.

There is no POSIX way to detect that we are in a subshell ($$ and $PPID are specified to remain unchanged), but we can detect it on Bash and fall back to ignoring the bug on other shells.

Signed-off-by: John Keeping <john@keeping.me.uk>
---
 t/test-lib-functions.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 0e80f37..6dffb8b 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -736,6 +736,11 @@ test_seq () {
 # what went wrong.
 
 test_when_finished () {
+	# We cannot detect when we are in a subshell in general, but by
+	# doing so on Bash is better than nothing (the test will
+	# silently pass on other shells).
+	test "${BASH_SUBSHELL-0}" = 0 ||
+	error "bug in test script: test_when_finished does nothing in a subshell"
 	test_cleanup="{ $*
 		} && (exit \"\$eval_ret\"); eval_ret=\$?; $test_cleanup"
 }

-- 
2.5.0.466.g9af26fa