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

quoted

quoted

+# 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