patch, 2 partsalways run all lint targets when running the test suite

I recently accidentally added a non-portable "echo -n" to a test suite helper which "make test" didn't show. This series attempts to detect such problems early when running the test suite.

The first patch includes the helper scripts to be tested too when running "make test-lint" (and thus the test-lint-shell-syntax target) in the test directory.

The second patch then uses all lint tests in the test run.

Jens Lehmann (2):
  t/Makefile: check helper scripts for non-portable shell commands too
  t/Makefile: always test all lint targets when running tests

 t/Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Currently only the "t[0-9][0-9][0-9][0-9]-*.sh" scripts are tested for shell incompatibilities using the check-non-portable-shell.pl script. This makes it easy to miss non-POSIX constructs added to one of the t/*lib*.sh helper scripts, as they aren't automatically detected.

Fix that by adding a THELPERS variable containing all shell scripts that
aren't tests and add these to the "test-lint-shell-syntax" target too.
---
 t/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Only the two targets "test-lint-duplicates" and "test-lint-executable" are currently executed when running the test target. This was done on purpose when the TEST_LINT variable was added in 81127d74. But as this does not include the "test-lint-shell-syntax" target added the same day in commit c7ce70ac, it is easy to accidentally add non portable shell constructs without noticing that when running the test suite.

Fix that by always running all lint tests unless the TEST_LINT variable is
overridden. If we add less accurate or slow tests later we could still
fall back to exclude them like 81127d74 proposed. But for now it is better
to include all lint tests until proven otherwise.
---
 t/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Jens Lehmann <Jens.Lehmann@web.de> writes:

I not running the lint-shell-syntax that is fundamentally flaky to avoid false positives is very much on purpose. The flakiness is not the fault of the implementor of the lint-shell-syntax, but comes from the approach taken to pretend that simple pattern matching can parse shell scripts. It may not complain on the current set of scripts, but that is not really by design but by accident.

So I am not very enthusiastic to see this change myself.

Am 07.07.2014 20:13, schrieb Junio C Hamano:

Ok, I understand we do not want to lightly risk false positives. I just noticed that I accidentally forgot to sign off this series, so I'd resend just the first patch with a proper SOB, ok?

On Tue, Jul 8, 2014 at 12:24 PM, Jens Lehmann <Jens.Lehmann@web.de> wrote:

Nah, let's do both and how it plays out. My not being very enthusiastic myself does not necessarily mean that it is bad for the project. Maybe most people like it and if I cannot bear with it I can always turn it off myself for my environment.

I just have a strange feeling that we may be seeing some twisted shell script updates and when the author gets asked why it was written in such a strange way, the answer might turn out to be "just to work around the false positive from the test-lint", which I would not want to see.

Am 09.07.2014 07:42, schrieb Junio C Hamano:

Me neither. But until then it might well be that the benefit of having this test on by default outweighs this potential problem. It would have surely detected my fingers typing "echo -n" without my brain being alert enough to catch this portability issue ;-)

This is the updated version with proper SOBs and an updated commit message for 2/2 which is trying to sum up the considerations raised in this thread.

Jens Lehmann (2):
  t/Makefile: check helper scripts for non-portable shell commands too
  t/Makefile: always test all lint targets when running tests

 t/Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Currently only the "t[0-9][0-9][0-9][0-9]-*.sh" scripts are tested for shell incompatibilities using the check-non-portable-shell.pl script. This makes it easy to miss non-POSIX constructs added to one of the t/*lib*.sh helper scripts, as they aren't automatically detected.

Fix that by adding a THELPERS variable containing all shell scripts that aren't tests and add these to the "test-lint-shell-syntax" target too.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
---
 t/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Only the two targets "test-lint-duplicates" and "test-lint-executable" are currently executed when running the test target. This was done on purpose when the TEST_LINT variable was added in 81127d74 to avoid twisted shell scripting by developers only to avoid false positives that might result from the rather simple minded tests, e.g. test-lint-shell-syntax. But it looks like it might be better to include all lint tests to help developers to detect non portable shell constructs before the patch is sent to the list and reviewed there.

Change the TEST_LINT variable to run all lint test unless the TEST_LINT variable is overridden. If we hit false positives more often than helping developers to avoid non-portable code (or add less accurate or slow tests later) we could still fall back to exclude them like 81127d74 proposed.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
---
 t/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

On Mon, Jul 07, 2014 at 11:13:11AM -0700, Junio C Hamano wrote:

Let me play devil's advocate for a moment.

Is lint-shell-syntax in fact flaky? I know we discussed false positives when it was originally added, but I think the current implementation tries hard to avoid them. Given that it provides no false positives on the current code base (without many people running it), it seems likely to stay that way. And the cost if we are wrong is either fixing the tool or disabling it (so worst case we are back where we started, modulo a little effort to enable it and then revert).

What do we gain? We have an extra line of defense that helps newer shell script writers fix their bugs before they make it to the list. That catches more bugs, and reduces effort for reviewers. And it is exactly these newer shell script writers that need the default flipped; they do not know about portability and the lint target in the first place.

I dunno. I am not that enthusiastic about the change, either, but I tend to think it will probably not hurt, and may help.

-Peff