Re: [PATCH 05/15] t/Makefile: optimize chainlint self-test

On Mon, Dec 13 2021, Fabian Stelzer wrote:

On 13.12.2021 09:27, Eric Sunshine wrote:

quoted

On Mon, Dec 13, 2021 at 5:22 AM Fabian Stelzer [off-list ref] wrote:

quoted

On 13.12.2021 01:30, Eric Sunshine wrote:

quoted

check-chainlint:
+      sed -e '/^# LINT: /d' $(patsubst %,chainlint/%.test,$(CHAINLINTTESTS)) >'$(CHAINLINTTMP_SQ)'/tests && \
+      cat $(patsubst %,chainlint/%.expect,$(CHAINLINTTESTS)) >'$(CHAINLINTTMP_SQ)'/expect && \
+      $(CHAINLINT) '$(CHAINLINTTMP_SQ)'/tests >'$(CHAINLINTTMP_SQ)'/actual && \
+      diff -u '$(CHAINLINTTMP_SQ)'/expect '$(CHAINLINTTMP_SQ)'/actual

If I read this right you are relying on the order of the .test & .expect
files to match. I did something similar in a test prereq which resulted in a
bug when setting the test_output_dir to something residing in /dev/shm,
since the order of files in /dev/shm is reversed (at least on some
platforms). Even though this should work as is I could see this leading to a
similar bug in the future.

It's not seen in the patch context, but earlier in the file we have:

   CHAINLINTTESTS = $(sort $(...,$(wildcard chainlint/*.test)))

which provides stability via `sort`, thus ensures that the order of
the ".test" and ".expect" match.

I think that addresses your concern (unless I misunderstand your observation).

Yes, thats what i meant. I didn't realize $CHAINLINTTESTS is already
the sorted glob. Thanks for clarifying.

Personally i find the initial for loop variant to be the most
readable.  Ævars makefile targets could be very nice too, but
especially:

+$(BUILT_CHAINLINTTESTS): | .build/chainlint
+$(BUILT_CHAINLINTTESTS): .build/%.actual: %
+       $(CHAINLINT) <$< | \
+	 sed -e '/^# LINT: /d' >$@ && \
+       diff -u $(basename $<).expect $@

i find very hard to grasp :/
I have no idea what is going on here: `<$< |` ?

It's a minor point, and not relevant to this series proceeding.

But just FWIW I think both of you are wrong about the potenital for a
".test" and ".expect" bug here.

I.e. yes the CHAINLINTTESTS variable is sorted:

    CHAINLINTTESTS = $(sort $(...,$(wildcard chainlint/*.test)))

But in Eric's patch we just have this relevant to this concern of
(paraphrased) "would it not be sorted break it?":

	+	sed -e '/^# LINT: /d' $(patsubst %,chainlint/%.test,$(CHAINLINTTESTS)) >'$(CHAINLINTTMP_SQ)'/tests && \
	+	cat $(patsubst %,chainlint/%.expect,$(CHAINLINTTESTS)) >'$(CHAINLINTTMP_SQ)'/expect && \

So it doesn't matter if it's sorted our not.

I.e. we've got {A,B,C}.{test,expect} files in a directory, and we're
constructing a "A.test" and "A.expect" via "$(patsubst)".

So if it's "A B C", "C B A", "A C B" etc. won't matter. We'll always get
".test" files corresponding to ".expect".

If it's not sorted we'll get failure output in an unexpected order, but
it won't matter to whether we detect a failure or not.