From 51e5c95792b7af3fb181e703b9b3fb8c05550d8a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustavo=20Andr=C3=A9=20dos=20Santos=20Lopes?=
 <gustavo.lopes@datadoghq.com>
Date: Tue, 20 Jan 2026 11:15:06 -0300
Subject: [PATCH] Add GIT_COMMIT cmake variable

Running git is not always possible, either because there's no git
checkout, there's no git available, or we're in a git subtree without
access to reference git files.

Allow passing GIT_COMMIT to cmake to bypass the git invocation.
---
 CMakeLists.txt      |  2 ++
 cmake/package.cmake | 25 +++++++++++++++----------
 cmake/shared.cmake  | 14 +++++++++-----
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6f4602044..4134fcf9d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,6 +34,8 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
 
+set(GIT_COMMIT "" CACHE STRING "Git commit hash (skips git invocation if set)")
+
 option(LIBDDWAF_BUILD_SHARED "Build shared library" ON)
 option(LIBDDWAF_BUILD_STATIC "Build shared library" ON)
 option(LIBDDWAF_TESTING "Load test subdirectories and targets" ON)
diff --git a/cmake/package.cmake b/cmake/package.cmake
index 927bb1eb4..b2b624909 100644
--- a/cmake/package.cmake
+++ b/cmake/package.cmake
@@ -22,20 +22,25 @@ set(CPACK_GENERATOR "TGZ")
 set(CPACK_SOURCE_GENERATOR "TGZ")
 
 ## Package name
-execute_process(COMMAND git describe --exact-match --tags HEAD
-    WORKING_DIRECTORY ${libddwaf_SOURCE_DIR}
-    OUTPUT_VARIABLE DDWAF_VERSION
-    OUTPUT_STRIP_TRAILING_WHITESPACE
-    ERROR_QUIET
-)
-
-if (NOT DDWAF_VERSION)
+if(GIT_COMMIT)
     set(DDWAF_VERSION ${CMAKE_PROJECT_VERSION})
-    execute_process(COMMAND git rev-parse --short HEAD
+    string(SUBSTRING "${GIT_COMMIT}" 0 7 SHORT_BUILD_ID)
+else()
+    execute_process(COMMAND git describe --exact-match --tags HEAD
         WORKING_DIRECTORY ${libddwaf_SOURCE_DIR}
-        OUTPUT_VARIABLE SHORT_BUILD_ID
+        OUTPUT_VARIABLE DDWAF_VERSION
         OUTPUT_STRIP_TRAILING_WHITESPACE
+        ERROR_QUIET
     )
+
+    if (NOT DDWAF_VERSION)
+        set(DDWAF_VERSION ${CMAKE_PROJECT_VERSION})
+        execute_process(COMMAND git rev-parse --short HEAD
+            WORKING_DIRECTORY ${libddwaf_SOURCE_DIR}
+            OUTPUT_VARIABLE SHORT_BUILD_ID
+            OUTPUT_STRIP_TRAILING_WHITESPACE
+        )
+    endif()
 endif()
 
 set(CPACK_PACKAGE_FILE_NAME ${CMAKE_PROJECT_NAME}-${DDWAF_VERSION}-${CMAKE_SYSTEM_NAME}-${LIBDDWAF_PACKAGE_PROCESSOR})
diff --git a/cmake/shared.cmake b/cmake/shared.cmake
index 42964059a..29bda900b 100644
--- a/cmake/shared.cmake
+++ b/cmake/shared.cmake
@@ -1,8 +1,12 @@
-execute_process(COMMAND git rev-parse HEAD
-    WORKING_DIRECTORY ${libddwaf_SOURCE_DIR}
-    OUTPUT_VARIABLE BUILD_ID
-    OUTPUT_STRIP_TRAILING_WHITESPACE
-)
+if(GIT_COMMIT)
+    set(BUILD_ID "${GIT_COMMIT}")
+else()
+    execute_process(COMMAND git rev-parse HEAD
+        WORKING_DIRECTORY ${libddwaf_SOURCE_DIR}
+        OUTPUT_VARIABLE BUILD_ID
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+endif()
 
 message(STATUS "Build id is ${BUILD_ID}")
 string(SUBSTRING "${BUILD_ID}" 0 2 BUILD_ID_PREFIX)