fix: including non branch changes in diff output (#973)

Co-authored-by: repo-ranger[bot] <39074581+repo-ranger[bot]@users.noreply.github.com>

.github/workflows/test.yml

@@ -210,6 +210,7 @@ jobs:
       matrix:
         platform: [ubuntu-latest]
         fetch-depth: [1, 2]
+        input-fetch_depth: [1, 50]
 
     steps:
       - name: Checkout to branch
@@ -220,6 +221,8 @@ jobs:
       - name: Run changed-files
         id: changed-files
         uses: ./
+        with:
+          fetch_depth: ${{ matrix.input-fetch_depth }}
 
       - name: Show output
         run: |

diff-sha.sh

@@ -168,8 +168,7 @@ else
     if [[ "$INPUT_SINCE_LAST_REMOTE_COMMIT" != "true" ]]; then
       echo "::debug::Fetching remote target branch..."
       # shellcheck disable=SC2086
-      git fetch -u --progress $EXTRA_ARGS --depth="$INPUT_FETCH_DEPTH" origin +refs/heads/"$TARGET_BRANCH":refs/remotes/origin/"$TARGET_BRANCH" 1>/dev/null
+      git fetch $EXTRA_ARGS -u --progress --deepen="$INPUT_FETCH_DEPTH" origin "$TARGET_BRANCH:$TARGET_BRANCH" 1>/dev/null
-      git branch --track "$TARGET_BRANCH" origin/"$TARGET_BRANCH" 1>/dev/null 2>&1 || true
     fi
   fi
 
@@ -209,10 +208,23 @@ else
         PREVIOUS_SHA=$GITHUB_EVENT_PULL_REQUEST_BASE_SHA
       fi
     else
-      PREVIOUS_SHA=$(git merge-base "$TARGET_BRANCH" "$CURRENT_SHA") && 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 rev-parse origin/"$TARGET_BRANCH") && exit_status=$? || exit_status=$?
+
+      if [[ -f .git/shallow ]]; then
+        # check if the merge base is in the local history
+        if ! git merge-base "$PREVIOUS_SHA" "$CURRENT_SHA"; then
+          echo "::debug::Merge base is not in the local history, fetching remote target branch..."
+          # Fetch more of the target branch history until the merge base is found
+          for i in {1..10}; do
+            # shellcheck disable=SC2086
+            git fetch $EXTRA_ARGS -u --progress --deepen="$INPUT_FETCH_DEPTH" origin "$TARGET_BRANCH:$TARGET_BRANCH" 1>/dev/null
+            if git merge-base "$PREVIOUS_SHA" "$CURRENT_SHA"; then
+              break
+            fi
+            echo "::debug::Merge base is not in the local history, fetching remote target branch again..."
+            echo "::debug::Attempt $i/10"
+          done
+        fi
       fi
     fi