diff --git a/diff-sha.sh b/diff-sha.sh
index 3bda566e..dc6c3a6c 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -226,9 +226,8 @@ else
           # shellcheck disable=SC2086
           git fetch $EXTRA_ARGS -u --progress --deepen="$depth" origin +"$GITHUB_REF":refs/remotes/origin/"$CURRENT_BRANCH"
 
-          PREVIOUS_SHA=$(git merge-base "$TARGET_BRANCH" "$CURRENT_SHA" 2>&1) && exit_status=$? || exit_status=$?
-
           if git diff --name-only --ignore-submodules=all "$PREVIOUS_SHA$DIFF$CURRENT_SHA" 1>/dev/null 2>&1; then
+            PREVIOUS_SHA=$(git merge-base "$TARGET_BRANCH" "$CURRENT_SHA" 2>&1) && exit_status=$? || exit_status=$?
             break
           fi
         done