lint: constant in conditional (was: Re: CVS commit: src/sys/sys)

[Roland Illig <roland.illig%gmx.de@localhost>]

Am 06.04.2025 um 03:24 schrieb Taylor R Campbell:
>> Date: Sat, 5 Apr 2025 19:18:20 +0200
>> From: Roland Illig <roland.illig%gmx.de@localhost>
>>
>> Would it be narrow enough to add /*CONSTCOND*/ to the definition of
>> ALIGNED_POINTER on i386 and amd64? Or would you consider this still too
>> broad?
>
> Might be reasonable.  But then we have a lot of predicates that might
> be used in conditionals but be constant on some architectures, which
> raises the question of which ones should be marked.
>
> I wonder how many real bugs -- true positives -- lint's
> constant-condition warnings find.

I have no idea about that number, as I hope that these issues would have
been fixed by now, before committing them.

I looked at the remaining warnings, and more than 95% of them are
useless, leaving at most 5% that are debatable. I didn't see a case
where that warning pointed at an obvious bug.

I'm fine disabling this check for lib/libc, or even entirely removing
the check from lint, as it doesn't find all constant conditions but
complains about many cases that are fine. The examples given in
tests/usr.bin/xlint/lint1/msg_161.c are not convincing enough to keep
this warning.

Roland