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 preprocessors 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will cause compilation of `version.c` ran by Meson to include `version-def.h` previously made by Make, which might be out of date. To explicitly tell the preprocessor which `version-def.h` to use, pass the absolute path of this file as macro GIT_VERSION_H to the preprocessor using option `-D` and have `version.c` `#include GIT_VERSION_H`. To remain working with other build systems than Meson, include "version-def.h" if that macro is not defined. Co-authored-by: Patrick Steinhardt <ps@xxxxxx> Signed-off-by: Toon Claes <toon@xxxxxxxxx> --- This is version 2 of the patch trying to ensure the Meson build does not include `version-def.h` created by Make. --- Changes in v2: - Instead of copying `version.c` to the Meson build directory, define a macro with the absolute path of `version-def.h` to include. - Link to v1: https://lore.kernel.org/r/20250113-toon-fix-meson-version-v1-1-9637e2be32e3@xxxxxxxxx --- Range-diff versus v1: 1: fad8163ff8 ! 1: c1ca203451 meson: ensure correct version-def.h is used @@ Commit message 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 + with double quotes, some preprocessors 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will cause compilation of `version.c` ran by Meson to include `version-def.h` previously made by Make, which might be out of date.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. + To explicitly tell the preprocessor which `version-def.h` to use, pass + the absolute path of this file as macro GIT_VERSION_H to the + preprocessor using option `-D` and have `version.c` `#include + GIT_VERSION_H`. To remain working with other build systems than Meson, + include "version-def.h" if that macro is not defined. + Co-authored-by: Patrick Steinhardt <ps@xxxxxx> Signed-off-by: Toon Claes <toon@xxxxxxxxx> ## meson.build ## -@@ meson.build: version_def_h = custom_target( - env: version_gen_environment, +@@ meson.build: libgit_version_library = static_library('git-version', + 'version.c', + version_def_h, + ], +- c_args: libgit_c_args, ++ c_args: libgit_c_args + [ ++ '-DGIT_VERSION_H="' + version_def_h.full_path() + '"', ++ ], + dependencies: libgit_dependencies, + include_directories: libgit_include_directories, ) + + ## version.c ## +@@ + #include "git-compat-util.h" + #include "version.h" +-#include "version-def.h" + #include "strbuf.h" -+# 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') ++#ifndef GIT_VERSION_H ++# include "version-def.h" ++#else ++# include GIT_VERSION_H ++#endif + - # 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, + const char git_version_string[] = GIT_VERSION; + const char git_built_from_commit_string[] = GIT_BUILT_FROM_COMMIT; + --- meson.build | 4 +++- version.c | 7 ++++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/meson.build b/meson.build index 0064eb64f546a6349a8694ce251bd352febda6fe..db27afa99986598aab22ada718f76a7a49238f24 100644 --- a/meson.build +++ b/meson.build @@ -1493,7 +1493,9 @@ libgit_version_library = static_library('git-version', 'version.c', version_def_h, ], - c_args: libgit_c_args, + c_args: libgit_c_args + [ + '-DGIT_VERSION_H="' + version_def_h.full_path() + '"', + ], dependencies: libgit_dependencies, include_directories: libgit_include_directories, ) diff --git a/version.c b/version.c index 4d763ab48dd76c0445e5ea390ff4c1f35c1a4b12..4786c4e0a54093ca947da27f8b712bd1ea351203 100644 --- a/version.c +++ b/version.c @@ -1,8 +1,13 @@ #include "git-compat-util.h" #include "version.h" -#include "version-def.h" #include "strbuf.h" +#ifndef GIT_VERSION_H +# include "version-def.h" +#else +# include GIT_VERSION_H +#endif + const char git_version_string[] = GIT_VERSION; const char git_built_from_commit_string[] = GIT_BUILT_FROM_COMMIT; --- base-commit: fbe8d3079d4a96aeb4e4529cc93cc0043b759a05 change-id: 20250113-toon-fix-meson-version-3d4d33fdabe3 Thanks -- Toon
