add an unshallow call for ci

cmake/tools/SetupGit.cmake

@@ -11,7 +11,45 @@ if(NOT GIT_PROGRAM)
   return()
 endif()
 
-set(GIT_DIFF_COMMAND ${GIT_PROGRAM} diff --no-color --name-only --diff-filter=AMCR origin/main HEAD)
+set(GIT_UNSHALLOW_COMMAND ${GIT_PROGRAM} fetch --unshallow)
+
+execute_process(
+  COMMAND
+    ${GIT_UNSHALLOW_COMMAND}
+  WORKING_DIRECTORY
+    ${CWD}
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+  OUTPUT_VARIABLE
+    GIT_UNSHALLOW
+  ERROR_STRIP_TRAILING_WHITESPACE
+  ERROR_VARIABLE
+    GIT_UNSHALLOW_ERROR
+  RESULT_VARIABLE
+    GIT_UNSHALLOW_RESULT
+)
+
+set(GIT_MERGEBASE_COMMAND ${GIT_PROGRAM} merge-base origin/main HEAD)
+
+execute_process(
+  COMMAND
+    ${GIT_MERGEBASE_COMMAND}
+  WORKING_DIRECTORY
+    ${CWD}
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+  OUTPUT_VARIABLE
+    GIT_MERGEBASE
+  ERROR_STRIP_TRAILING_WHITESPACE
+  ERROR_VARIABLE
+    GIT_MERGEBASE_ERROR
+  RESULT_VARIABLE
+    GIT_MERGEBASE_RESULT
+)
+if(NOT GIT_MERGEBASE_RESULT EQUAL 0)
+  message(${WARNING} "Command failed: ${GIT_MERGEBASE_COMMAND}" "\n" ${GIT_MERGEBASE_ERROR})
+  return()
+endif()
+
+set(GIT_DIFF_COMMAND ${GIT_PROGRAM} diff --no-color --name-only --diff-filter=AMCR ${GIT_MERGEBASE} HEAD)
 
 execute_process(
   COMMAND
@@ -29,7 +67,7 @@ execute_process(
 )
 
 if(NOT GIT_DIFF_RESULT EQUAL 0)
-  message(${WARNING} "Command failed: ${GIT_DIFF_COMMAND} ${GIT_DIFF_ERROR}")
+  message(${WARNING} "Command failed: ${GIT_DIFF_COMMAND}" "\n" ${GIT_DIFF_ERROR})
   return()
 endif()