Re: [PATCH v4] meson: regenerate config-list.h when Documentation changes

[Patrick Steinhardt <ps@pks.im>]

On Mon, Feb 16, 2026 at 05:28:57PM -0500, D. Ben Knoble wrote:
> The Meson-based build doesn't know when to rebuild config-list.h, so the
> header is sometimes stale.
> 
> For example, an old build directory might have config-list.h from before
> 4173df5187 (submodule: introduce extensions.submodulePathConfig,
> 2026-01-12), which added submodule.<name>.gitdir to the list. Without
> it, t9902-completion.sh fails. Regenerating the config-list.h artifact
> from sources fixes the artifact and the test.
> 
> Teach the meson build to depend on the Documentation files that
> generate-configlist.sh reads by having it an additional output as a list
> of dependency files, since Meson does not have (or want) builtin support
> for globbing like Make. We assume that if a user adds a new file under
> Documentation/config then they will also edit one of the existing files
> to include that new file, and that will trigger a rebuild.
> 
> Also mark the generator script as a dependency.
> 
> Combining the following commands helps debug dependencies:
> 
>     ninja -C <builddir> -t deps config-list.h
>     ninja -C <builddir> -t browse config-list.h
> 
> The former lists all the dependencies discovered from our output ".d"
> file (the config documentation) and the latter shows the dependency on
> the script itself, among other useful edges in the dependency graph.

Good hint, thanks for putting it here.

> diff --git a/generate-configlist.sh b/generate-configlist.sh
> index 75c39ade209..63a2e8b6938 100755
> --- a/generate-configlist.sh
> +++ b/generate-configlist.sh
> @@ -36,3 +37,12 @@ print_config_list ()
>  	echo
>  	print_config_list
>  } >"$OUTPUT"
> +
> +if test -n "$DEPFILE"
> +then
> +	for doc in "$SOURCE_DIR"/Documentation/*config.adoc \
> +		"$SOURCE_DIR"/Documentation/config/*.adoc
> +	do
> +		printf "$OUTPUT: %s\n" "$(printf '%s\n' "$doc" | sed 's/[# ]/\\&/g')"

Tiny nit: can't we simplify this to "$(echo "$doc" | sed ...)"?

> diff --git a/meson.build b/meson.build
> index 3a1d12caa4b..e4b8f1e33d2 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -720,11 +720,14 @@ endif
>  
>  builtin_sources += custom_target(
>    output: 'config-list.h',
> +  depfile: 'config-list.h.d',
> +  depend_files: [ 'generate-configlist.sh' ],
>    command: [
>      shell,
> -    meson.current_source_dir() + '/generate-configlist.sh',
> +    meson.current_source_dir() / 'generate-configlist.sh',
>      meson.current_source_dir(),
>      '@OUTPUT@',
> +    '@DEPFILE@',
>    ],
>    env: script_environment,
>  )

And this looks as expected now, too. I also verified locally that this
correctly rebuilds things when either the script or any of the files
change.

I wonder whether we also want to have a second patch on top to adjust
our Makefile? E.g. something like this:

diff --git a/Makefile b/Makefile
index 47ed9fa7fd..ed82775ec2 100644
--- a/Makefile
+++ b/Makefile
@@ -2688,8 +2688,10 @@ $(BUILT_INS): git$X
 
 config-list.h: generate-configlist.sh
 
-config-list.h: Documentation/*config.adoc Documentation/config/*.adoc
-	$(QUIET_GEN)$(SHELL_PATH) ./generate-configlist.sh . $@
+config-list.h: generate-configlist.sh
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-configlist.sh . $@ .depend/config-list.h.d
+
+-include .depend/config-list.h.d
 
 command-list.h: generate-cmdlist.sh command-list.txt
 

Please feel free to skip this part though.

Thanks!

Patrick