chore: Fix commit SHA for GitHub PRs

Author: mathbunnyru

.github/actions/cmake/action.yml

@@ -57,6 +57,9 @@ runs:
         STATIC: "${{ inputs.static == 'true' && 'ON' || 'OFF' }}"
         TIME_TRACE: "${{ inputs.time_trace == 'true' && 'ON' || 'OFF' }}"
         PACKAGE: "${{ inputs.package == 'true' && 'ON' || 'OFF' }}"
+        # GitHub creates merge commits for pull requests, so we need to use `github.event.pull_request.head.sha`
+        # to get the actual commit SHA of the PR branch.
+        GITHUB_HEAD_SHA: "${{ github.event.pull_request.head.sha || github.sha }}"
       run: |
         cmake \
           -B "${BUILD_DIR}" \

cmake/ClioVersion.cmake

@@ -30,11 +30,17 @@ else ()
     OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY
   )
 
-  set(GIT_COMMAND rev-parse --short HEAD)
-  execute_process(
-    COMMAND ${GIT_EXECUTABLE} ${GIT_COMMAND} WORKING_DIRECTORY ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE REV
-    OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY
-  )
+  if (DEFINED ENV{GITHUB_HEAD_SHA})
+    # GitHub creates merge commits for pull requests, so we need to use `github.event.pull_request.head.sha` to get the
+    # actual commit SHA of the PR branch. We set $GITHUB_HEAD_SHA in the cmake action
+    set(REV $ENV{GITHUB_HEAD_SHA})
+  else ()
+    set(GIT_COMMAND rev-parse --short HEAD)
+    execute_process(
+      COMMAND ${GIT_EXECUTABLE} ${GIT_COMMAND} WORKING_DIRECTORY ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE REV
+      OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY
+    )
+  endif ()
 
   set(CLIO_VERSION "${DATE}-${BRANCH}-${REV}")
   set(DOC_CLIO_VERSION "develop")