diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9e252e6d..f1c232f7 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -334,6 +334,41 @@ jobs:
           echo "Expected: (failure) got ${{ steps.changed-files-specific.outcome }}"
           exit 1
 
+  test-submodules:
+    name: Test changed-files with submodule
+    runs-on: ${{ matrix.platform }}
+    strategy:
+      fail-fast: false
+      max-parallel: 4
+      matrix:
+        platform: [ubuntu-latest]
+
+    steps:
+      - name: Checkout to branch
+        uses: actions/checkout@v3
+        with:
+          submodules: recursive
+
+      - name: Run changed-files with submodule
+        id: changed-files
+        uses: ./
+        with:
+          base_sha: "85bd869"
+          sha: "adde7bb"
+          fetch_depth: 60000
+
+      - name: Verify added files
+        if: steps.changed-files.outputs.added_files != 'test/demo/test/test.txt'
+        run: |
+          echo "Expected: (test/demo/test/test.txt) got ${{ steps.changed-files.outputs.added_files }}"
+          exit 1
+
+      - name: Show output
+        run: |
+          echo "${{ toJSON(steps.changed-files.outputs) }}"
+        shell:
+          bash
+
   test:
     name: Test changed-files
     runs-on: ${{ matrix.platform }}
diff --git a/diff-sha.sh b/diff-sha.sh
index 1f3e370d..f8827ae1 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -4,7 +4,7 @@ set -euo pipefail
 
 INITIAL_COMMIT="false"
 GITHUB_OUTPUT=${GITHUB_OUTPUT:-""}
-EXTRA_ARGS="--no-tags --prune --no-recurse-submodules"
+EXTRA_ARGS="--no-tags --prune --recurse-submodules"
 PREVIOUS_SHA=""
 CURRENT_SHA=""
 DIFF="..."
@@ -60,7 +60,9 @@ if [[ -z $GITHUB_EVENT_PULL_REQUEST_BASE_REF ]]; then
   if [[ -f .git/shallow ]]; then
     echo "Fetching remote refs..."
     # shellcheck disable=SC2086
-    git fetch $EXTRA_ARGS -u --progress --deepen="$INPUT_FETCH_DEPTH" origin "$CURRENT_BRANCH" 1>/dev/null || true
+    git fetch $EXTRA_ARGS -u --progress --deepen="$INPUT_FETCH_DEPTH" origin +refs/heads/"$CURRENT_BRANCH":refs/remotes/origin/"$CURRENT_BRANCH" 1>/dev/null
+    # shellcheck disable=SC2086
+    git submodule foreach git fetch $EXTRA_ARGS -u --progress --deepen="$INPUT_FETCH_DEPTH" || true
   fi
 
   echo "::debug::Getting HEAD SHA..."
@@ -218,7 +220,7 @@ else
           # 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
+            git fetch $EXTRA_ARGS -u --progress --deepen="$INPUT_FETCH_DEPTH" origin +refs/heads/"$TARGET_BRANCH":refs/remotes/origin/"$TARGET_BRANCH" 1>/dev/null
             if git merge-base "$PREVIOUS_SHA" "$CURRENT_SHA" 1>/dev/null 2>&1; then
               break
             fi
diff --git a/get-changed-paths.sh b/get-changed-paths.sh
index 5cf7fd2f..94fe149e 100755
--- a/get-changed-paths.sh
+++ b/get-changed-paths.sh
@@ -56,13 +56,13 @@ function get_dirname_max_depth() {
 }
 
 function json_output() {
-  JQ_ARGS="-sR"
+  local jq_args="-sR"
   if [[ "$INPUT_JSON_RAW_FORMAT" == "true" ]]; then
-    JQ_ARGS="$JQ_ARGS -r"
+    jq_args="$jq_args -r"
   fi
 
   # shellcheck disable=SC2086
-  jq $JQ_ARGS 'split("\n") | map(select(. != "")) | @json' | sed -r 's/^"|"$//g' | tr -s /
+  jq $jq_args 'split("\n") | map(select(. != "")) | @json' | sed -r 's/^"|"$//g' | tr -s /
 }
 
 function get_diff() {
@@ -71,33 +71,33 @@ function get_diff() {
   local filter="$3"
 
   while IFS='' read -r sub; do
-    sub_commit_pre="$(git diff "$base$DIFF$sha" -- "$sub" | { grep '^[-]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
+    sub_commit_pre="$(git diff "$base" "$sha" -- "$sub" | { grep '^[-]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
     if [[ $exit_status -ne 0 ]]; then
-      echo "::error::Failed to get previous commit for submodule ($sub) between: $base$DIFF$sha"
-      exit 1
+      echo "::warning::Failed to get previous commit for submodule ($sub) between: $base $sha. Please ensure that submodules are initialized and up to date. See: https://github.com/actions/checkout#usage" >&2
     fi
 
-    sub_commit_cur="$(git diff "$base$DIFF$sha" -- "$sub" | { grep '^[+]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
+    sub_commit_cur="$(git diff "$base" "$sha" -- "$sub" | { grep '^[+]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
     if [[ $exit_status -ne 0 ]]; then
-      echo "::error::Failed to get current commit for submodule ($sub) between: $base$DIFF$sha"
-      exit 1
+      echo "::warning::Failed to get current commit for submodule ($sub) between: $base $sha. Please ensure that submodules are initialized and up to date. See: https://github.com/actions/checkout#usage" >&2
     fi
 
     if [ -n "$sub_commit_cur" ]; then
       (
         cd "$sub" && (
           # the strange magic number is a hardcoded "empty tree" commit sha
-          get_diff "${sub_commit_pre:-4b825dc642cb6eb9a060e54bf8d69288fbee4904}" "${sub_commit_cur}" "$filter" | awk -v r="$sub" '{ print "" r "/" $0}'
+          git diff --diff-filter="$filter" --name-only --ignore-submodules=all "${sub_commit_pre:-4b825dc642cb6eb9a060e54bf8d69288fbee4904}" "${sub_commit_cur}" | awk -v r="$sub" '{ print "" r "/" $0}' 2>/dev/null
         )
-      )
+      ) || {
+        echo "::warning::Failed to get changed files for submodule ($sub) between: ${sub_commit_pre:-4b825dc642cb6eb9a060e54bf8d69288fbee4904} ${sub_commit_cur}. Please ensure that submodules are initialized and up to date. See: https://github.com/actions/checkout#usage" >&2
+      }
     fi
   done < <(git submodule | awk '{print $2}')
 
-  git diff --diff-filter="$filter" --name-only --ignore-submodules=all --no-merges "$base$DIFF$sha" && exit_status=$? || exit_status=$?
+  git diff --diff-filter="$filter" --name-only --ignore-submodules=all "$base$DIFF$sha" && exit_status=$? || exit_status=$?
 
   if [[ $exit_status -ne 0 ]]; then
-    echo "::error::Failed to get changed files between: $base$DIFF$sha"
-    exit 1
+    echo "::error::Failed to get changed files between: $base$DIFF$sha" >&2
+    return 1
   fi
 }
 
@@ -106,33 +106,33 @@ function get_renames() {
   local sha="$2"
 
   while IFS='' read -r sub; do
-    sub_commit_pre="$(git diff "$base$DIFF$sha" -- "$sub" | { grep '^[-]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
+    sub_commit_pre="$(git diff "$base" "$sha" -- "$sub" | { grep '^[-]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
     if [[ $exit_status -ne 0 ]]; then
-      echo "::error::Failed to get previous commit for submodule ($sub) between: $base$DIFF$sha"
-      exit 1
+      echo "::warning::Failed to get previous commit for submodule ($sub) between: $base $sha. Please ensure that submodules are initialized and up to date. See: https://github.com/actions/checkout#usage" >&2
     fi
 
-    sub_commit_cur="$(git diff "$base$DIFF$sha" -- "$sub" | { grep '^[+]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
+    sub_commit_cur="$(git diff "$base" "$sha" -- "$sub" | { grep '^[+]Subproject commit' || true; } | awk '{print $3}')" && exit_status=$? || exit_status=$?
     if [[ $exit_status -ne 0 ]]; then
-      echo "::error::Failed to get current commit for submodule ($sub) between: $base$DIFF$sha"
-      exit 1
+      echo "::warning::Failed to get current commit for submodule ($sub) between: $base $sha. Please ensure that submodules are initialized and up to date. See: https://github.com/actions/checkout#usage" >&2
     fi
 
     if [ -n "$sub_commit_cur" ]; then
       (
         cd "$sub" && (
           # the strange magic number is a hardcoded "empty tree" commit sha
-          get_renames "${sub_commit_pre:-4b825dc642cb6eb9a060e54bf8d69288fbee4904}" "${sub_commit_cur}" | awk -v r="$sub" '{ print "" r "/" $0}'
+          git log --name-status --ignore-submodules=all "${sub_commit_pre:-4b825dc642cb6eb9a060e54bf8d69288fbee4904}" "${sub_commit_cur}" | { grep -E "^R" || true; } | awk -F '\t' -v d="$INPUT_OLD_NEW_SEPARATOR" '{print $2d$3}' | awk -v r="$sub" '{ print "" r "/" $0}'
         )
-      )
+      ) || {
+        echo "::warning::Failed to get renamed files for submodule ($sub) between: ${sub_commit_pre:-4b825dc642cb6eb9a060e54bf8d69288fbee4904} ${sub_commit_cur}. Please ensure that submodules are initialized and up to date. See: https://github.com/actions/checkout#usage" >&2
+      }
     fi
   done < <(git submodule | awk '{print $2}')
 
   git log --name-status --ignore-submodules=all "$base" "$sha" | { grep -E "^R" || true; } | awk -F '\t' -v d="$INPUT_OLD_NEW_SEPARATOR" '{print $2d$3}' && exit_status=$? || exit_status=$?
 
   if [[ $exit_status -ne 0 ]]; then
-    echo "::error::Failed to get renamed files between: $base → $sha"
-    exit 1
+    echo "::error::Failed to get renamed files between: $base → $sha" >&2
+    return 1
   fi
 }
 
diff --git a/test/demo b/test/demo
index 3b8549eb..83ccca9b 160000
--- a/test/demo
+++ b/test/demo
@@ -1 +1 @@
-Subproject commit 3b8549eb19fb6d4ff2017cbe27d2cec353cace93
+Subproject commit 83ccca9b633cc41dc1f04e690e4a3a8026a01359