Fixed bug with detecting initial commit.

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

action.yml

@@ -208,7 +208,7 @@ runs:
         INPUT_FETCH_DEPTH: ${{ inputs.fetch_depth }}
         INPUT_SINCE_LAST_REMOTE_COMMIT: ${{ inputs.since_last_remote_commit }}
     - name: Glob match
-      uses: tj-actions/glob@v17.2.5
+      uses: tj-actions/glob@0fe7f8d9e113caff328f057851c9be33b7a50fbf # v17.2.5
       id: glob
       with:
         files: ${{ inputs.files }}
@@ -255,7 +255,7 @@ runs:
         INPUT_HAS_CUSTOM_PATTERNS: ${{ steps.glob.outputs.has-custom-patterns }}
         INPUT_JSON_RAW_FORMAT: ${{ inputs.json_raw_format }}
     - name: Generate output files
-      uses: tj-actions/json2file@v1.4.2
+      uses: tj-actions/json2file@46d3707a327c0049b276be5977a89354b9310003 # v1.4.2
       if: inputs.write_output_files == 'true'
       with:
         outputs: ${{ toJSON(steps.changed-files.outputs) }}

diff-sha.sh

@@ -133,23 +133,23 @@ if [[ -z $GITHUB_EVENT_PULL_REQUEST_BASE_REF ]]; then
         if [[ "$GITHUB_EVENT_FORCED" == "false" || -z "$GITHUB_EVENT_FORCED" ]]; then
           PREVIOUS_SHA=$GITHUB_EVENT_BEFORE && exit_status=$? || exit_status=$?
         else
-          PREVIOUS_SHA=$(git rev-list -n 1 "HEAD^") && exit_status=$? || exit_status=$?
+          PREVIOUS_SHA=$(git rev-list -n 1 "HEAD^" || true) && exit_status=$? || exit_status=$?
         fi
       else
-        PREVIOUS_SHA=$(git rev-list -n 1 "HEAD^") && exit_status=$? || exit_status=$?
+        PREVIOUS_SHA=$(git rev-list -n 1 "HEAD^" || true) && exit_status=$? || exit_status=$?
       fi
 
       if [[ -z "$PREVIOUS_SHA" || "$PREVIOUS_SHA" == "0000000000000000000000000000000000000000" ]]; then
-        PREVIOUS_SHA=$(git rev-list -n 1 "HEAD^") && exit_status=$? || exit_status=$?
+        PREVIOUS_SHA=$(git rev-list -n 1 "HEAD^" || true) && exit_status=$? || exit_status=$?
       fi
 
-      if [[ "$PREVIOUS_SHA" == "$CURRENT_SHA" ]]; then
+      if [[ -z "$PREVIOUS_SHA" || "$PREVIOUS_SHA" == "$CURRENT_SHA" ]]; then
-        if ! git rev-parse "$PREVIOUS_SHA^1" &>/dev/null; then
+        if ! git rev-parse "$CURRENT_SHA^1" &>/dev/null; then
           INITIAL_COMMIT="true"
           PREVIOUS_SHA=$(git rev-parse "$CURRENT_SHA")
           echo "::warning::Initial commit detected no previous commit found."
         else
-          PREVIOUS_SHA=$(git rev-parse "$PREVIOUS_SHA^1")
+          PREVIOUS_SHA=$(git rev-parse "$CURRENT_SHA^1")
         fi
       else
         if [[ -z "$PREVIOUS_SHA" ]]; then