Update clang-format action

Signed-off-by: Ping Xie <pingxie@google.com>

.github/workflows/clang-format.yml

@@ -24,12 +24,16 @@ jobs:
         # Run clang-format and capture the diff
         cd src
         clang-format -i **/*.c **/*.h
-        git diff --exit-code
+        # Capture the diff output
+        DIFF=$(git diff)
+        if [ ! -z "$DIFF" ]; then
+          echo "::set-output name=diff::$DIFF"
+        fi
       shell: bash
 
     - name: Check for formatting changes
-      if: ${{ failure() }}
+      if: steps.clang-format.outputs.diff
       run: |
-        echo "Code is not formatted correctly."
+        echo "Code is not formatted correctly. Here is the diff:"
+        echo "${{ steps.clang-format.outputs.diff }}"
         exit 1
-

src/.clang-format-ignore

@@ -14,4 +14,3 @@ sha1.*
 sha256.*
 siphash.c
 strl.c
-unit/test_files.h

src/unit/test_files.h

@@ -1,4 +1,5 @@
 /* Do not modify this file, it's automatically generated from utils/generate-unit-test-header.py */
+/* clang-format off */
 typedef int unitTestProc(int argc, char **argv, int flags);
 
 typedef struct unitTest {

utils/generate-unit-test-header.py

@@ -26,6 +26,7 @@
                     test_suites.append({'file': file, 'tests': tests})
         test_suites.sort(key=lambda test_suite: test_suite['file'])
         output.write("""/* Do not modify this file, it's automatically generated from utils/generate-unit-test-header.py */
+/* clang-format off */
 typedef int unitTestProc(int argc, char **argv, int flags);
 
 typedef struct unitTest {
@@ -56,4 +57,4 @@
 """)
         for test_suite in test_suites:
             output.write('    {{"{0}", __{1}}},\n'.format(test_suite['file'], test_suite['file'].replace('.c', '_c')))
-        output.write('};\n')
+        output.write('};\n')