Re: [PATCH] meson: fix building mergetool docs

[Patrick Steinhardt <ps@pks.im>]

On Mon, Feb 09, 2026 at 10:08:43AM +0000, Phillip Wood wrote:
> From: Phillip Wood <phillip.wood@dunelm.org.uk>
> 
> Building the documentation with meson when the build directory is
> not an immediate subdirectory of the source directory prints the
> following error
> 
> [2/1349] Generating Documentation/mer... command (wrapped by meson to set env)
> ../../Documentation/generate-mergetool-list.sh: line 15: ../git-mergetool--lib.sh: No such file or directory

Oh, good catch.

> The build does not fail because the failure is upstream of a pipe. Fix
> the error by passing the correct source directory when meson runs
> "generate-mergetool-list.sh". As that script sets $MERGE_TOOLS_DIR
> we do not need to set it in the environment when running the script.

Huh.

> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> ---
> We should probably change the script so that error is not ignored
> as well. I also wonder if we should use something more exotic than
> "build" as the meson build directory in our CI though that wont make
> any difference if the script does not fail.

We probably could, I guess. And making the script more solid would
definitely be a very good step regardless of whether or not we want to
use a more esoteric build directory.

> diff --git a/Documentation/meson.build b/Documentation/meson.build
> index f02dbc20cbc..d0e557c2078 100644
> --- a/Documentation/meson.build
> +++ b/Documentation/meson.build
> @@ -353,13 +353,10 @@ foreach mode : [ 'diff', 'merge' ]
>      command: [
>        shell,
>        '@INPUT@',
> -      '..',
> +      meson.project_source_root(),
>        mode,
>        '@OUTPUT@'
>      ],

Makes sense. I assume that this is the only change required to make
out-of-source builds work?

> -    env: [
> -      'MERGE_TOOLS_DIR=' + meson.project_source_root() / 'mergetools',
> -    ],

Hm. We indeed set this environment variable in the script itself. I was
a bit puzzled at first because we don't export it, and it's not used
directly. But we source "git-mergetool--lib.sh", which in turn uses the
variable, so it shouldn't be needed to export it.

So this looks like a nice simplification to me, thanks!

Patrick