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From: Fabian Stelzer <fs@gigacodes.de>
To: Eric Sunshine <sunshine@sunshineco.com>
Cc: "Git List" <git@vger.kernel.org>, "Jeff King" <peff@peff.net>,
	"Elijah Newren" <newren@gmail.com>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [PATCH 05/15] t/Makefile: optimize chainlint self-test
Date: Mon, 13 Dec 2021 17:14:19 +0100	[thread overview]
Message-ID: <20211213161419.cwamlunrgz3adrhh@fs> (raw)
In-Reply-To: <CAPig+cSXHBMgOUycL0cXuVCb_PJ2=x2w4wUkc7eQQueyk=0Uzw@mail.gmail.com>

On 13.12.2021 11:02, Eric Sunshine wrote:
>On Mon, Dec 13, 2021 at 10:43 AM Fabian Stelzer <fs@gigacodes.de> wrote:
>> 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 $@
>>
>> i find very hard to grasp :/
>> I have no idea what is going on here: `<$< |` ?
>
>Ya, that line-noise is an unfortunate combination of shell and
>Makefile gobbledygook. The `$<` is effectively the source file (the
>file being passed into chainlint.sed), and the rest of it is just
>normal shell. `<` is redirection (using the source file `$<` as
>stdin), and `|` is the pipe operator (sending the output of
>chainlint.sed to another `sed`), and capturing it all via shell `>`
>redirection in `$@` which is the Makefile variable for the target
>file.
>

Thanks, that explains it nicely. I'm not familiar enough with makefile 
syntax.

>Anyhow, although the commit message tries to sell this change as some
>sort of optimization, it's really in preparation for the new chainlint
>which wants to check all tests in all files with a single invocation
>rather than being invoked over and over and over. The self-test files
>also require more preprocessing to work with the new chainlint, so the
>implementation of `check-chainlint` gets rather more complex once the
>end state is reached. I'll think about it a bit, but at the moment,
>I'm still leaning toward this intermediate step as being beneficial to
>reaching the end state. However, my opinion could change since the way
>this is done here was probably influenced by an earlier iteration of
>the new chainlint, but now that the implementation of the new
>chainlint is concrete, it may not be especially important to do it
>this way.

I don't mind much either way and i tend to favor the efficient variant as 
well. On the other hand i can also see some bug mixing up the contents of 
these files producing a huge diff with no good indication for the developer 
of what has happened.

  parent reply	other threads:[~2021-12-13 16:14 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-13  6:30 [PATCH 00/15] generalize chainlint self-tests Eric Sunshine
2021-12-13  6:30 ` [PATCH 01/15] t/chainlint/*.test: don't use invalid shell syntax Eric Sunshine
2021-12-13  6:30 ` [PATCH 02/15] t/chainlint/*.test: fix invalid test cases due to mixing quote types Eric Sunshine
2021-12-13  6:30 ` [PATCH 03/15] t/chainlint/*.test: generalize self-test commentary Eric Sunshine
2021-12-13  6:30 ` [PATCH 04/15] t/chainlint/one-liner: avoid overly intimate chainlint.sed knowledge Eric Sunshine
2021-12-13  6:30 ` [PATCH 05/15] t/Makefile: optimize chainlint self-test Eric Sunshine
2021-12-13 10:09   ` [RFC PATCH] t/Makefile: use dependency graph for "check-chainlint" Ævar Arnfjörð Bjarmason
2021-12-14  7:44     ` Eric Sunshine
2021-12-14 12:34       ` Ævar Arnfjörð Bjarmason
2021-12-13 10:22   ` [PATCH 05/15] t/Makefile: optimize chainlint self-test Fabian Stelzer
2021-12-13 14:27     ` Eric Sunshine
2021-12-13 15:43       ` Fabian Stelzer
2021-12-13 16:02         ` Eric Sunshine
2021-12-13 16:11           ` Ævar Arnfjörð Bjarmason
2021-12-13 17:05             ` Eric Sunshine
2021-12-13 17:25               ` Eric Sunshine
2021-12-13 19:33                 ` Ævar Arnfjörð Bjarmason
2021-12-13 21:37                   ` Eric Sunshine
2021-12-13 16:14           ` Fabian Stelzer [this message]
2021-12-16 13:17         ` Ævar Arnfjörð Bjarmason
2021-12-16 15:47           ` Eric Sunshine
2021-12-16 19:26             ` Ævar Arnfjörð Bjarmason
2021-12-13  6:30 ` [PATCH 06/15] chainlint.sed: improve ?!AMP?! placement accuracy Eric Sunshine
2021-12-13  6:30 ` [PATCH 07/15] chainlint.sed: improve ?!SEMI?! " Eric Sunshine
2021-12-13  6:30 ` [PATCH 08/15] chainlint.sed: tolerate harmless ";" at end of last line in block Eric Sunshine
2021-12-13  6:30 ` [PATCH 09/15] chainlint.sed: drop unnecessary distinction between ?!AMP?! and ?!SEMI?! Eric Sunshine
2021-12-13  6:30 ` [PATCH 10/15] chainlint.sed: drop subshell-closing ">" annotation Eric Sunshine
2021-12-13  6:30 ` [PATCH 11/15] chainlint.sed: make here-doc "<<-" operator recognition more POSIX-like Eric Sunshine
2021-12-13  6:30 ` [PATCH 12/15] chainlint.sed: don't mistake `<< word` in string as here-doc operator Eric Sunshine
2021-12-13  6:30 ` [PATCH 13/15] chainlint.sed: stop throwing away here-doc tags Eric Sunshine
2021-12-13  6:30 ` [PATCH 14/15] chainlint.sed: swallow comments consistently Eric Sunshine
2021-12-13  6:30 ` [PATCH 15/15] chainlint.sed: stop splitting "(..." into separate lines "(" and "..." Eric Sunshine
2021-12-15  0:00 ` [PATCH 00/15] generalize chainlint self-tests Elijah Newren
2021-12-15  3:15   ` Eric Sunshine

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