[PATCH RFC v7 04/22] Makefile: propagate Git version via generated header

From: Patrick Steinhardt <ps@pks.im>
Date: Nov 15, 2024, 07:21 UTC
Message-ID: <20241115-pks-meson-v7-4-47ec19b780b2@pks.im>
In-Reply-To: <20241115-pks-meson-v7-0-47ec19b780b2@pks.im>

We set up a couple of preprocessor macros when compiling Git that propagate the version that Git was built from to `git version` et al. The way this is set up makes it harder than necessary to reuse the infrastructure across the different build systems.

Refactor this such that we generate a "version-def.h" header via `GIT-VERSION-GEN` instead.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 .gitignore                          |  1 +
 Makefile                            | 12 +++++-------
 contrib/buildsystems/CMakeLists.txt | 16 ++++++++++++----
 version-def.h.in                    |  8 ++++++++
 version.c                           |  1 +
 5 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/.gitignore b/.gitignore
index 6687bd6db4c0a6adf02292a9cb545d3e5270e2b0..e17963e84252fa094c10f5e84c0e3724153c819c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -195,6 +195,7 @@
 /config-list.h
 /command-list.h
 /hook-list.h
+/version-def.h
 *.tar.gz
 *.dsc
 *.deb
diff --git a/Makefile b/Makefile
index 6c55c47e961047a8e9a80ab948e21c7466cf54de..28807f6586a69d6ce0abf1b20ce31ca58e9d02a9 100644
--- a/Makefile
+++ b/Makefile
@@ -2508,13 +2508,11 @@ PAGER_ENV_CQ_SQ = $(subst ','\'',$(PAGER_ENV_CQ))
 pager.sp pager.s pager.o: EXTRA_CPPFLAGS = \
 	-DPAGER_ENV='$(PAGER_ENV_CQ_SQ)'
 
-version.sp version.s version.o: GIT-VERSION-FILE GIT-USER-AGENT
-version.sp version.s version.o: EXTRA_CPPFLAGS = \
-	'-DGIT_VERSION="$(GIT_VERSION)"' \
-	'-DGIT_USER_AGENT=$(GIT_USER_AGENT_CQ_SQ)' \
-	'-DGIT_BUILT_FROM_COMMIT="$(shell \
-		GIT_CEILING_DIRECTORIES="$(CURDIR)/.." \
-		git rev-parse -q --verify HEAD 2>/dev/null)"'
+version-def.h: version-def.h.in GIT-VERSION-GEN GIT-VERSION-FILE GIT-USER-AGENT
+	$(QUIET_GEN)GIT_USER_AGENT="$(GIT_USER_AGENT)" $(SHELL_PATH) ./GIT-VERSION-GEN "$(shell pwd)" $< $@+
+	@if cmp $@+ $@ >/dev/null 2>&1; then $(RM) $@+; else mv $@+ $@; fi
+
+version.sp version.s version.o: version-def.h
 
 $(BUILT_INS): git$X
 	$(QUIET_BUILT_IN)$(RM) $@ && \
diff --git a/contrib/buildsystems/CMakeLists.txt b/contrib/buildsystems/CMakeLists.txt
index 752479cac59d3833e7fff9239ebea75179692bf4..b9ebe2ef74e37d5fad51f6e23aa234c563cad392 100644
--- a/contrib/buildsystems/CMakeLists.txt
+++ b/contrib/buildsystems/CMakeLists.txt
@@ -229,10 +229,7 @@ add_compile_definitions(PAGER_ENV="LESS=FRX LV=-c"
 			GIT_HTML_PATH="share/doc/git-doc"
 			DEFAULT_HELP_FORMAT="html"
 			DEFAULT_GIT_TEMPLATE_DIR="share/git-core/templates"
-			GIT_VERSION="${PROJECT_VERSION}.GIT"
-			GIT_USER_AGENT="git/${PROJECT_VERSION}.GIT"
-			BINDIR="bin"
-			GIT_BUILT_FROM_COMMIT="")
+			BINDIR="bin")
 
 if(WIN32)
 	set(FALLBACK_RUNTIME_PREFIX /mingw64)
@@ -668,6 +665,17 @@ parse_makefile_for_sources(libgit_SOURCES "LIB_OBJS")
 
 list(TRANSFORM libgit_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
 list(TRANSFORM compat_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
+
+add_custom_command(OUTPUT "${CMAKE_BINARY_DIR}/version-def.h"
+	COMMAND "${SH_EXE}" "${CMAKE_SOURCE_DIR}/GIT-VERSION-GEN"
+		"${CMAKE_SOURCE_DIR}"
+		"${CMAKE_SOURCE_DIR}/version-def.h.in"
+		"${CMAKE_BINARY_DIR}/version-def.h"
+	DEPENDS "${SH_EXE}" "${CMAKE_SOURCE_DIR}/GIT-VERSION-GEN"
+		"${CMAKE_SOURCE_DIR}/version-def.h.in"
+	VERBATIM)
+list(APPEND libgit_SOURCES "${CMAKE_BINARY_DIR}/version-def.h")
+
 add_library(libgit ${libgit_SOURCES} ${compat_SOURCES})
 
 #libxdiff
diff --git a/version-def.h.in b/version-def.h.in
new file mode 100644
index 0000000000000000000000000000000000000000..347995df0611e19428cf96ec9539f0dcfea999d2
--- /dev/null
+++ b/version-def.h.in
@@ -0,0 +1,8 @@
+#ifndef VERSION_DEF_H
+#define VERSION_DEF_H
+
+#define GIT_VERSION "@GIT_VERSION@"
+#define GIT_BUILT_FROM_COMMIT "@GIT_BUILT_FROM_COMMIT@"
+#define GIT_USER_AGENT "@GIT_USER_AGENT@"
+
+#endif /* VERSION_DEF_H */
diff --git a/version.c b/version.c
index 41b718c29e1b9fc2981d7d14a3d25e69c31a3030..7adc4d51ff25a0841607c21807deaf20721252de 100644
--- a/version.c
+++ b/version.c
@@ -1,5 +1,6 @@
 #include "git-compat-util.h"
 #include "version.h"
+#include "version-def.h"
 #include "strbuf.h"
 
 const char git_version_string[] = GIT_VERSION;

-- 
2.47.0.251.gb31fb630c0.dirty