On Thu, Jun 06, 2024 at 09:41:56AM +0200, Patrick Steinhardt wrote:

quoted

If we want to get coverage of -Og, I'd suggest doing it in a job that is
otherwise overlapping with another (maybe linux-TEST-vars, which I think
is otherwise a duplicate build?).

I don't think linux-TEST-vars would be a good candidate for this because
it uses Ubuntu 20.04. Ideally, we'd want to have a test run with an
up-to-date version of Ubuntu so that we also get a recent version of the
compiler toolchain.

Oof, yeah, I agree that if the point is to find obscure warnings, newer
is going to be better.

I kind of wonder whether we should revamp this pedantic job in the first
place. The consequence of that job is that our codebase needs to be
compile cleanly with `-Wpedantic`. So if that is a requirement anyway,
why don't we run all jobs with `DEVOPTS=pedantic` and just drop this job
altogether? This may surface some additional warnings on platforms where
we currently don't set that, but is that a bad thing?

Yeah, if we always compile cleanly with pedantic, then I don't see why
it wouldn't just be the default for DEVELOPER=1. The point of that flag
is to be as picky as possible so that we catch things early. If some
platform can't handle it (let's imagine Windows or something), then I
think we should be explicitly _disabling_ pedantic there.

The only downside I can think of is that we stop compiling on Fedora,
which may have a more up-to-date GCC version than Ubuntu. But if the
goal of this job was to _really_ get an up-to-date compiler toolchain,
then we should rather pick a rolling release distro like Arch. Otherwise
I find this to be of dubious benefit.

There may be some value in general in compiling on multiple distros, as
a sort of "unknown unknowns" thing. We don't know what we might turn up,
but exposing ourselves to more variables may lead to catching failures
before users see them.

I don't know if Fedora was specifically chosen for recent gcc there, or
if it was simply for variety.

Once again, these overlapping variables within various jobs make it hard
to reason about (but I don't propose normalizing all of them; that would
increase the amount of CPU work by a lot; I am just grumbling).

But yeah, between Arch and Fedora, I don't have an opinion. Doing both
might even be valuable, if we are shoving random variations into random
jobs. ;)

If we merge it into the other jobs, then I'd just pick any random job
that uses "ubuntu:latest" like "linux-gcc-default" to compile with
`-Og`.

That would be OK with me. I also think it would be OK to do nothing for
now. We saw one case where "-Og" found a warning that "-O2" didn't. We
could wait to see if it happens twice before acting. I dunno.

-Peff