Re: lint warnings

[Christos Zoulas <christos%zoulas.com@localhost>]

On 2022-06-28 12:10 am, Roland Illig wrote:
> Am 27.06.2022 um 20:20 schrieb 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:    src
> > > > > Committed By:   rillig
> > > > > Date:       Fri Jun 24 20:16:21 UTC 2022
> > > > >
> > > > > Modified Files:
> > > > >      src/tests/usr.bin/xlint/lint1: msg_247.c
> > > > >      src/usr.bin/xlint/lint1: tree.c
> > > > >
> > > > > Log Message:
> > > > > lint: do not warn about pointer cast between sockaddr variants
> > >
> > > 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 *).
>
> This '(void *)' or '(const void *)' is exactly what I meant with
> 'intermediate cast'. This cast would also hide casts between completely
> unrelated pointer types, therefore I prefer the direct cast from one
> sockaddr pointer to another.

Yes, I meant there is only one cast needed.

> Lint warns about the direct casts in all cases that seem dubious, while
> it treats a cast chain involving '(void *)' as an 'I know what I'm
> doing' from the author. This exact behavior makes sense to me.
>
> > > ... cast from 'pointer to array[20] of double' to 'pointer
> > > to double': I don't see how that could be dangerous ...
> >
> > ... I was thinking to wrap them all up into a pedantic flag instead.
>
> Did you mean this as 'I will implement this pedantic flag', or rather 
> as
> 'you should implement this'? Right now, I won't do that because I'm
> lacking any good examples that would demonstrate the usefulness of this
> new flag. If you add that flag, could you add a few examples to the
> existing tests? Having these examples is much easier than digging
> through the code, trying to find examples retrospectively 25 years 
> later. :)

I meant that I don't want to lose all those warnings in pedantic mode, 
but
I was not planning to add it. It seems useful to still have a way for 
lint
report the cases where they are usage-specific correct, but not 
linguistically
correct.

christos