[PATCH] meson: ensure correct version-def.h is used

From: Toon Claes <toon@iotcl.com>
Date: Jan 13, 2025, 10:28 UTC
Message-ID: <20250113-toon-fix-meson-version-v1-1-9637e2be32e3@iotcl.com>

To build the libgit-version library, Meson first generates `version-def.h` in the build directory. Then it compiles `version.c` into a library. During compilation, Meson tells to include both the build directory and the project root directory.

However, when the user previously has compiled Git using Make, they will have a `version-def.h` file in project root directory as well. Because `version-def.h` is included in `version.c` using the #include directive with double quotes, some compilers will look for the header file in the same directory as the source file. This will cause compilation of `version.c` ran by Meson to include `version-def.h` previously made by Make, which might be out of date.

Copy `version.c` to the build directory before compiling it to ensure `version-def.h` from the build directory is used.

Signed-off-by: Toon Claes <toon@iotcl.com>
---
---
 meson.build | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/meson.build b/meson.build
index 0064eb64f546a6349a8694ce251bd352febda6fe..8ecb22c80e4fc3f194e97c14dbf83f541d72b25b 100644
--- a/meson.build
+++ b/meson.build
@@ -1486,11 +1486,15 @@ version_def_h = custom_target(
   env: version_gen_environment,
 )
 
+# Because most compilers prefer header files in the same directory as the source
+# file, copy version.c to the build directory.
+version_c = fs.copyfile(meson.current_source_dir() / 'version.c', 'version.c')
+
 # Build a separate library for "version.c" so that we do not have to rebuild
 # everything when the current Git commit changes.
 libgit_version_library = static_library('git-version',
   sources: [
-    'version.c',
+    version_c,
     version_def_h,
   ],
   c_args: libgit_c_args,

---

base-commit: fbe8d3079d4a96aeb4e4529cc93cc0043b759a05
change-id: 20250113-toon-fix-meson-version-3d4d33fdabe3

Thanks
--
Toon