Re: [Buildroot] [RFC PATCH 0/2] use `command -v' instead of `which'

From: "Yann E. MORIN" <yann.morin.1998@free.fr>
To: Arnout Vandecappelle <arnout@mind.be>
Cc: buildroot@buildroot.org
Subject: Re: [Buildroot] [RFC PATCH 0/2] use `command -v' instead of `which'
Date: Thu, 30 Sep 2021 22:04:02 +0200	[thread overview]
Message-ID: <20210930200402.GO1504958@scaer> (raw)
In-Reply-To: <fee5adb3-0cd8-3538-bf3e-d04af8153007@mind.be>

Petr, Arnout, All,

On 2021-09-26 23:32 +0200, Arnout Vandecappelle spake thusly:
> On 21/09/2021 22:51, Petr Vorel wrote:
> >I've tested the patchset on dash as the default shell. But it certainly
> >deserve more people to have look and test.
> 
>  Well, as the commit message says: it's POSIX so it should be supported by
> everything. which has a much smaller chance of being supported.

This is causing quite some issues.

First, 'command -v' does not behave the same way 'which' used to, when
passed more than one parameter, because some shells are not compliant to
POSIX (this might be a bug, but nonetheless it affects the most widely
used shell out there, bash) [0].

Second, this is causing a lot of error messages:

    $ make defconfig
    [...]
    $ make help
    make[1]: command: Command not found
    [...]

The original commit reports that 'which' is broken in Debian, but I was
not able to reproduce in Bullseye, where 'which' still works as expected
and does not emit any extra warning.

So, we are trying to fix something that is broken on a development
version of Debian, but that still works in all known released
distributions.

I usually am quite in favour of sticking to POSIX tools, but which has
been ubiquitous in the past 30 years or so, and I would consider that
Debian's which *is* broken for reporting such deprecation warnings.

So, I suggest that we do revert this patch, and work on a better
transition away from which, if at all. One very quick solution would be
to bundle our own which in Buildroot and then we'd have a quick way out
of that Debian's mess...

Anyway, I'd vote "revert".

Regards,
Yann E. MORIN.

[0] https://lore.kernel.org/buildroot/YVTIghzHs82uFBIe@pevik/T/#m95c17eb8374e4e3dd6eee700d397aa12cca0739e

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