[CI][format] Explicitly pass extensions to git-clang-format (take 2)

This is a second attempt to land 7620fe0, which was reverted in 9572388
because it caused formatting not to be enforced for several patches.

.github/workflows/pr-code-format.yml

@@ -80,7 +80,7 @@ jobs:
         # Create an empty comments file so the pr-write job doesn't fail.
         run: |
           echo "[]" > comments &&
-          python ./code-format-tools/llvm/utils/git/code-format-helper.py \
+          python ./llvm/utils/git/code-format-helper.py \
             --write-comment-to-file \
             --token ${{ secrets.GITHUB_TOKEN }} \
             --issue-number $GITHUB_PR_NUMBER \

libcxx/include/vector

@@ -739,7 +739,8 @@ public:
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT {
     size_type __old_size = size();
     __clear();
-    __annotate_shrink(__old_size);
+    __annotate_shrink
+    (__old_size);
   }
 
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void resize(size_type __sz);

llvm/utils/git/code-format-helper.py

@@ -210,12 +210,23 @@ def format_run(self, changed_files: List[str], args: FormatArgs) -> Optional[str
         if not cpp_files:
             return None
 
-        cf_cmd = [self.clang_fmt_path, "--diff"]
+        cf_cmd = [self.clang_fmt_path, "--verbose", "--diff"]
 
         if args.start_rev and args.end_rev:
             cf_cmd.append(args.start_rev)
             cf_cmd.append(args.end_rev)
 
+        # Gather the extension of all modified files and pass them explicitly to git-clang-format.
+        # This prevents git-clang-format from applying its own filtering rules on top of ours.
+        extensions = set()
+        for file in cpp_files:
+            _, ext = os.path.splitext(file)
+            extensions.add(
+                ext.strip(".")
+            )  # Exclude periods since git-clang-format takes extensions without them
+        cf_cmd.append("--extensions")
+        cf_cmd.append("{}".format(",".join(extensions)))
+
         cf_cmd.append("--")
         cf_cmd += cpp_files
 
@@ -225,6 +236,9 @@ def format_run(self, changed_files: List[str], args: FormatArgs) -> Optional[str
         proc = subprocess.run(cf_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         sys.stdout.write(proc.stderr.decode("utf-8"))
 
+        print("LDIONNE: return code of cmd was {}".format(proc.returncode))
+        print("LDIONNE: output of cmd was:\n{}".format(proc.stdout.decode("utf-8")))
+
         if proc.returncode != 0:
             # formatting needed, or the command otherwise failed
             if args.verbose: