Add git-based build information for better issue tracking (#1232)

* Add git-based build information for better issue tracking

* macOS fix

* "build (hash)" and "CMAKE_SOURCE_DIR" changes

* Redo "CMAKE_CURRENT_SOURCE_DIR" and clearer build messages

* Fix conditional dependency on missing target

* Broke out build-info.cmake, added find_package fallback, and added build into to all examples, added dependencies to Makefile

* 4 space indenting for cmake, attempt to clean up my mess in Makefile

* Short hash, less fancy Makefile, and don't modify build-info.h if it wouldn't change it

2 files changed, 75 insertions, 0 deletions

diff --git a/scripts/build-info.cmake b/scripts/build-info.cmake
new file mode 100644
index 0000000..fb46ed2
--- /dev/null
+++ b/scripts/build-info.cmake
@@ -0,0 +1,53 @@
+set(TEMPLATE_FILE "${CMAKE_BINARY_DIR}/BUILD_INFO.h.in")
+set(HEADER_FILE "${CMAKE_CURRENT_SOURCE_DIR}/build-info.h")
+set(BUILD_NUMBER 0)
+set(BUILD_COMMIT "unknown")
+
+# Look for git
+find_package(Git)
+if(NOT Git_FOUND)
+    execute_process(
+        COMMAND which git
+        OUTPUT_VARIABLE GIT_EXECUTABLE
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    if(NOT GIT_EXECUTABLE STREQUAL "")
+        set(Git_FOUND TRUE)
+        message(STATUS "Found Git using 'which': ${GIT_EXECUTABLE}")
+    else()
+        message(WARNING "Git not found using 'find_package' or 'which'. Build info will not be accurate. Consider installing Git or ensuring it is in the PATH.")
+    endif()
+endif()
+
+# Get the commit count and hash
+if(Git_FOUND)
+    execute_process(
+        COMMAND ${GIT_EXECUTABLE} rev-parse --short HEAD
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+        OUTPUT_VARIABLE HEAD
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        RESULT_VARIABLE GIT_HEAD_RESULT
+    )
+    execute_process(
+        COMMAND ${GIT_EXECUTABLE} rev-list --count HEAD
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+        OUTPUT_VARIABLE COUNT
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        RESULT_VARIABLE GIT_COUNT_RESULT
+    )
+    if(GIT_HEAD_RESULT EQUAL 0 AND GIT_COUNT_RESULT EQUAL 0)
+        set(BUILD_COMMIT ${HEAD})
+        set(BUILD_NUMBER ${COUNT})
+    endif()
+endif()
+
+# Only write the header if it's changed to prevent unnecessary recompilation
+if(EXISTS ${HEADER_FILE})
+    file(STRINGS ${HEADER_FILE} CONTENTS REGEX "BUILD_COMMIT \"([^\"]*)\"")
+    list(GET CONTENTS 0 EXISTING)
+    if(NOT EXISTING STREQUAL "#define BUILD_COMMIT \"${BUILD_COMMIT}\"")
+        configure_file(${TEMPLATE_FILE} ${HEADER_FILE})
+    endif()
+else()
+    configure_file(${TEMPLATE_FILE} ${HEADER_FILE})
+endif()
diff --git a/scripts/build-info.sh b/scripts/build-info.sh
new file mode 100755
index 0000000..507d7e1
--- /dev/null
+++ b/scripts/build-info.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+BUILD_NUMBER="0"
+BUILD_COMMIT="unknown"
+
+REV_LIST=$(git rev-list --count HEAD)
+if [ $? -eq 0 ]; then
+  BUILD_NUMBER=$REV_LIST
+fi
+
+REV_PARSE=$(git rev-parse --short HEAD)
+if [ $? -eq 0 ]; then
+  BUILD_COMMIT=$REV_PARSE
+fi
+
+echo "#ifndef BUILD_INFO_H"
+echo "#define BUILD_INFO_H"
+echo ""
+echo "#define BUILD_NUMBER $BUILD_NUMBER"
+echo "#define BUILD_COMMIT \"$BUILD_COMMIT\""
+echo ""
+echo "#endif // BUILD_INFO_H"