Re: [PATCH] xen: let ASSERT_UNREACHABLE() WARN() in non-debug builds

[Juergen Gross <jgross@xxxxxxxx>]

On 24.08.22 13:12, Jan Beulich wrote:
> On 24.08.2022 12:45, Juergen Gross wrote:
> > On 24.08.22 12:35, Jan Beulich wrote:
> > > On 24.08.2022 12:22, Juergen Gross wrote:
> > > > Hitting an ASSERT_UNREACHABLE() is always wrong, so even in production
> > > > builds a warning seems to be appropriate when hitting one.
> > > I disagree, for two reasons: This violates the implication of NDEBUG
> > > meaning ASSERT() and friends expand to no actual code. Plus if doing so
> > This is something we can change IMHO.
> >
> > > for ASSERT_UNREACHABLE(), why would we not do the same for ASSERT()?
> > There are multiple reasons to have ASSERT()s. Some serve as a kind of
> > documentation (e.g. to document that the programmer thought of a special
> > case not being possible), or they are meant to catch hard to diagnose
> > bugs rather early instead of letting them hit later in a situation where
> > it wouldn't be clear what caused them. Adding a WARN() for all of these
> > cases isn't really appropriate, especially as this might impact
> > performance due to added tests, which isn't the case for theoretically
> > unreachable code.
> >
> > > There's a reason we have ASSERT() and friends and, independently,
> > > WARN_ON() / BUG_ON() et al.
> > We might want to introduce something like ASSERT_OR_WARN(). I'm sure
> > this could be useful in some cases.
> I'm curious why in such cases it can't just be WARN_ON().
It won't result in test failure of debug builds.

In the end I'm not feeling really strong here, so I'm fine to drop this
patch.


Juergen

Attachment: OpenPGP_0xB0DE9DD628BF132F.asc
Description: OpenPGP public key

Attachment: OpenPGP_signature
Description: OpenPGP digital signature