Re: [PATCH v2 06/11] meson: wire up generation of distribution archive

On Tue, Jan 21, 2025 at 01:37:23PM +0100, Toon Claes wrote:

Patrick Steinhardt [off-list ref] writes:

quoted

Meson knows to generate distribution archives via `meson dist`. In
addition to generating the archive itself, this target also knows to
compile and execute tests from that archive, which helps to ensure that
the result is an adequate drop-in replacement for the versioned project.

While this already works as-is, one omission is that we don't propagate
the commit that this is built from into the resulting archive. This can
be fixed though by adding a distribution script that propagates the
version into the "version" file, which GIT-VERSION-GEN knows to read if
present.

Use GIT-VERSION-GEN to populate that file. As the script is executed in
the build directory, not in the directory where we generate the archive,
we have adapt it to honor the "MESON_DIST_ROOT" environment variable.

I failed to understand why you couldn't pass the absolute path of the
output file to GIT-VERSION-GEN. So I looked at the previous version of
this patch, and it seems you explain better over there.

I was testing things locally and tried this line for the last argument
to the script:

  run_command(shell, '-c', 'echo $MESON_DIST_ROOT', capture: true, check: true).stdout().strip() / 'version',

And I think I understand it better now. Meson does not execute this when
you run `meson dist`, but when it (re)generates it's build files. At
that stage $MESON_DIST_ROOT is not set.

It's unfortunate we have to learn GIT-VERSION-GEN about the
$MESON_DIST_ROOT environment variable, but I don't see any other way.

Hm. Thinking about it a bit more there is an alternative:

    meson.add_dist_script(
      shell,
      '-c',
      '"$1" "$2" "$3" --format="@GIT_VERSION@" "$MESON_DIST_ROOT/version"',
      'GIT-VERSION-GEN',
      shell,
      meson.current_source_dir() / 'GIT-VERSION-GEN',
      meson.current_source_dir(),
    )

I think this is a much better solution as it doesn't require us to teach
the script about `MESON_DIST_ROOT`.

Patrick