Re: [PATCH v2 4/5] Makefile: respect build info declared in "config.mak"

From: Jeff King <peff@peff.net>
Date: Dec 28, 2024, 19:43 UTC
Message-ID: <20241228194345.GA1535629@coredump.intra.peff.net>
In-Reply-To: <Z2XAiDC4pJ9OjTpC@pks.im>

On Fri, Dec 20, 2024 at 08:07:52PM +0100, Patrick Steinhardt wrote:

Show 20 quoted lines

> > > +# Never include it on the first read-through, only after make has tried to
> > > +# refresh includes. We do not want the old values to pollute our new run of the
> > > +# rule above.
> > > +ifdef MAKE_RESTARTS
> > >  -include GIT-VERSION-FILE
> > > +endif
> [...]
> Okay, I did find an issue where it does not work:
> 
>     $ git clean -dfx
>     $ make GIT-USER-AGENT
>     $ cat GIT-USER-AGENT
>     git/
>     $ cat GIT-VERSION-FILE
>     cat: GIT-VERSION-FILE: No such file or directory
> 
> It does not generate the version file at all anymore when it's not an
> explicit dependency. While I could of course add the missing dependency
> I don't know whether there are any other implicit dependencies that
> would be broken, as well. My gut feeling says "probably".

Doh, of course. We really want to say "do include this and consider it a dependency, but don't read it yet". But I don't think there's a way to tell make to do that.

I looked over your alternative approach with the OVERRIDE variable. I can't think of any downsides, aside from the general head-spinning complexity. ;) So that seems like a good approach for now (and I see it's already in master. Yay).

-Peff