enabling W=1 by default

[Andy Shevchenko]

On Wed, Oct 23, 2024 at 09:52:09AM +0200, Alexander Dahl wrote:
> Am Tue, Oct 22, 2024 at 04:23:07PM +0300 schrieb Andy Shevchenko:
> > On Mon, Oct 21, 2024 at 06:32:21PM +0200, Simon Glass wrote:
> > > On Mon, 21 Oct 2024 at 16:27, Andy Shevchenko
> > > <andriy.shevchenko at linux.intel.com> wrote:
> > > >
> > > > looking at the redness of the output of `make W=1` here is the question:
> > > > isn't it a good time to enable `make W=1` by default. Yes, I understand
> > > > the impact, but at least we can do it mandatory for a _new_ code submitted to
> > > > U-Boot, right?
> > > >
> > > > Ideally I would have what Linux kernel has for a few releases already, i.e.
> > > > Werror by default and getting close to make a clean builds with that and
> > > > make W=1` at least against default configurations (yeah, with U-Boot there is
> > > > probably no default, but sandbox one).
> > > 
> > > Warnings should be warnings...
> > 
> > Yes, and ideally the code should not have warnings, right?
> 
> +1
> 
> > Otherwise how can we do better? It's quite similar to what you wrote WRT
> > documenting the function prototypes, the same applies to the new contribution
> > WRT `make W=1`.
> > 
> > > if you would like to enable it for CI that is fine by me,
> > 
> > Yes, that's the idea, but I'm not the owner of any U-Boot CIs,
> > hence it's a proposal.
> > 
> > > but the U-Boot makefile shouldn't do it. It defeats the purpose of
> > > having a distinction between errors and warnings.
> > 
> > While it's not what I wanted, I disagree on your comment. The idea is to make
> > rules stricter (for new code) to make it better and that's why Linus enabled
> > Werror by default in the Linux kernel. And personally I consider that as a good
> > thing to follow.
> 
> Long term experience: each time you upgrade your toolchain you get new
> warnings.  Each package (u-boot, kernel, userland, does not matter
> which) enabling -Werror breaks the BSP build.  What should a developer
> do then?  Fix each warning in each foreign project and bring it
> upstream?  Or disable -Werror?  Last thing is what is usually done.
> You can see several patches in buildroot or ptxdist disabling -Werror
> for this reason.

That's why the set of enabled/disabled warnings are spread over W=<n> and hence
hidden when known to be PITA. W=1 is kinda special in a sense that we put the
warnings that might affect code generation, size of the binary, etc. In some cases
it even might prevent security bugs.

-- 
With Best Regards,
Andy Shevchenko