diff --git a/diff-sha.sh b/diff-sha.sh
index 7dba02fd..ea00ba8d 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -226,7 +226,7 @@ else
           # shellcheck disable=SC2086
           git fetch $EXTRA_ARGS -u --progress --deepen="$depth" origin +"$GITHUB_REF":refs/remotes/origin/"$CURRENT_BRANCH"
 
-          PREVIOUS_SHA=$(git merge-base origin/"$TARGET_BRANCH" "$CURRENT_SHA" 2>&1)
+          PREVIOUS_SHA=$(git merge-base origin/"$TARGET_BRANCH" "$CURRENT_SHA" 2>&1) && exit_status=$? || exit_status=$?
 
           if [[ $depth -gt $max_depth ]]; then
             echo "::error::Unable to locate a common ancestor between $TARGET_BRANCH and $CURRENT_SHA"