Re: lint warnings (was: Re: CVS commit: src)

[christos%astron.com@localhost (Christos Zoulas)]

In article <68ea25e4-a22b-4fbc-af8c-30c4195d2f24%gmx.de@localhost>,
Roland Illig  <roland.illig%gmx.de@localhost> wrote:
>27.06.2022 01:20:20 Christos Zoulas <christos%astron.com@localhost>:
>
>> In article <20220624201621.EF2AFFB1B%cvs.NetBSD.org@localhost>,
>> Roland Illig <source-changes-d%NetBSD.org@localhost> wrote:
>>> -=-=-=-=-=-
>>>
>>> Module Name:Â Â Â  src
>>> Committed By:Â Â  rillig
>>> Date:Â Â Â Â Â Â  Fri Jun 24 20:16:21 UTC 2022
>>>
>>> Modified Files:
>>> Â Â Â  src/tests/usr.bin/xlint/lint1: msg_247.c
>>> Â Â Â  src/usr.bin/xlint/lint1: tree.c
>>>
>>> Log Message:
>>> lint: do not warn about pointer cast between sockaddr variants
>>
>> Doesn't gcc warn for this?
>
>No, it doesn't. As we compile most of our code with -Werror, we would
>have noticed that.

I think that I've seen some pointer aliasing warning, but I could be wrong.

>I don't want to add any new command line switches to lint for specific
>cases like these, as we will quickly run out of letters. Instead, I'd
>rather define a "profile" named "NetBSD-userland" or "NetBSD-external"
>or "NetBSD-kernel". In these profiles, optional warnings could be
>switched using descriptive names, in addition to specific message IDs.
>These profiles would also allow to turn specific warnings into errors.

That is fine.

>My expectation of lint is that it warns me about possible bugs, and
>casting between the sockaddr variants is required by the API, therefore
>I don't see a point in flagging it as a possible bug.
>
>Or would you rather fix all the current warnings by adding an
>intermediate cast to 'void *'? That would be a lot of work, plus the
>intermediate cast can hide other typos.

There is no intermediate cast needed; you can just cast the sockaddr flavor
to (void *) or (const void *).

>Similarly for the cast from 'pointer to array[20] of double' to 'pointer
>to double': I don't see how that could be dangerous, therefore I
>switched off this warning unconditionally. Lint now misses casts between
>pointers to arrays of the same base type but different lengths, but
>pointers to arrays are rare enough that I simply ignored this case. In
>practice, these cases typically wrap the array in a struct.
>
>The state from 4 days ago where we had 12000 warnings of this kind
>alone, most of which were noise, was not acceptable to me, as nobody can
>be expected to walk through this amount of warnings, repeatedly checking
>for false positives just to find the 5% of the warnings that might be
>interesting.

Yes, and I was thinking to wrap them all up into a pedantic flag instead.


christos