build: gracefully handle error in git-version #19289

- only update git-version if both of these conditions are met:
    - `git` command succeeds
    - `versiondef_git.h` would change (SHA1-diff)
- else print a status/warning message

also move version generation out of Lua into cmake.

src/nvim/CMakeLists.txt

@@ -222,31 +222,17 @@ function(get_preproc_output varname iname)
   endif()
 endfunction()
 
-# Handle generating version from Git.
-set(use_git_version 0)
-if(NVIM_VERSION_MEDIUM)
-  message(STATUS "NVIM_VERSION_MEDIUM: ${NVIM_VERSION_MEDIUM}")
-elseif(EXISTS ${PROJECT_SOURCE_DIR}/.git)
-  find_program(GIT_EXECUTABLE git)
-  if(GIT_EXECUTABLE)
-    message(STATUS "Using NVIM_VERSION_MEDIUM from Git")
-    set(use_git_version 1)
-  else()
-    message(STATUS "Skipping version-string generation (cannot find git)")
-  endif()
-endif()
-if(use_git_version)
-  # Create a update_version_stamp target to update the version during build.
-  file(RELATIVE_PATH relbuild "${PROJECT_SOURCE_DIR}" "${CMAKE_BINARY_DIR}")
-  add_custom_target(update_version_stamp ALL
-    COMMAND ${LUA_PRG} scripts/update_version_stamp.lua
-      ${relbuild}/cmake.config/auto/versiondef_git.h
-      "v${NVIM_VERSION_MAJOR}.${NVIM_VERSION_MINOR}.${NVIM_VERSION_PATCH}${NVIM_VERSION_PRERELEASE}"
-    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    BYPRODUCTS ${CMAKE_BINARY_DIR}/cmake.config/auto/versiondef_git.h)
-else()
-  file(WRITE ${CMAKE_BINARY_DIR}/cmake.config/auto/versiondef_git.h "")
-endif()
+set(NVIM_VERSION_GIT_H ${PROJECT_BINARY_DIR}/cmake.config/auto/versiondef_git.h)
+add_custom_target(update_version_stamp
+  COMMAND ${CMAKE_COMMAND}
+    -DNVIM_VERSION_MAJOR=${NVIM_VERSION_MAJOR}
+    -DNVIM_VERSION_MINOR=${NVIM_VERSION_MINOR}
+    -DNVIM_VERSION_PATCH=${NVIM_VERSION_PATCH}
+    -DNVIM_VERSION_PRERELEASE=${NVIM_VERSION_PRERELEASE}
+    -DOUTPUT=${NVIM_VERSION_GIT_H}
+    -P ${PROJECT_SOURCE_DIR}/cmake/GenerateVersion.cmake
+  WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+  BYPRODUCTS ${NVIM_VERSION_GIT_H})
 
 # NVIM_GENERATED_FOR_HEADERS: generated headers to be included in headers
 # NVIM_GENERATED_FOR_SOURCES: generated headers to be included in sources
@@ -280,9 +266,9 @@ foreach(sfile ${NVIM_SOURCES}
   get_preproc_output(PREPROC_OUTPUT ${gf_i})
 
   set(depends "${HEADER_GENERATOR}" "${sfile}")
-  if(use_git_version AND "${f}" STREQUAL "version.c")
+  if("${f}" STREQUAL "version.c")
     # Ensure auto/versiondef_git.h exists after "make clean".
-    list(APPEND depends update_version_stamp)
+    list(APPEND depends "${NVIM_VERSION_GIT_H}")
   endif()
   add_custom_command(
     OUTPUT "${gf_c_h}" "${gf_h_h}"