Re: [PATCH v2 3/4] Makefiles: change search through $(MAKEFLAGS) for GNU make 4.4

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 30, 2022, 04:28 UTC
Message-ID: <xmqqk03dyskc.fsf@gitster.g>
In-Reply-To: <patch-v2-3.4-6db7dd74e52-20221129T140159Z-avarab@gmail.com>

Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:

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> Since GNU make 4.4 the semantics of the $(MAKEFLAGS) variable has
> changed in a backward-incompatible way, as its "NEWS" file notes:
>
>   Previously only simple (one-letter) options were added to the MAKEFLAGS
>   variable that was visible while parsing makefiles.  Now, all options are
>   available in MAKEFLAGS.  If you want to check MAKEFLAGS for a one-letter
>   option, expanding "$(firstword -$(MAKEFLAGS))" is a reliable way to return
>   the set of one-letter options which can be examined via findstring, etc.

Wow.  That's a bold move for GNU make folks to make.

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> This upstream change meant that e.g.:
>
> 	make man
>
> Would become very noisy, because in shared.mak we rely on extracting
> "s" from the $(MAKEFLAGS), which now contains long options like
> "--jobserver-auth=fifo:<path>", which we'll conflate with the "-s"
> option.

Do our uses of $(MAKEFLAGS) for the $(PRINT_DIR) and the $(QUIET) macros that do not affect correctness? $(QUIET) thing I suspect will merely be annoyance, but $(PRINT_DIR) might affect correctness depending on how $(MAKE) output is being used.

I have to wonder how many projects they have broken with this change ;-).

In any case, this seems like a good thing to do. I am not sure if this is so urgent to add in the -rc period, or can safely wait post release.

Thanks.