renderdiff: add initial code for updating goldens (#8349)

- Code for parsing tag in commit message
- Add placeholder for pulling and updating goldens in the script.

test/renderdiff/src/workflow_presubmit_msg.py

@@ -0,0 +1,46 @@
+# Copyright (C) 2025 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from utils import execute
+
+def get_last_commit():
+  res, o = execute('git log -1')
+  commit, author, date, _, title, *desc = o.split('\n')
+
+  desc = [l.strip() for l in desc[1:]]
+  if len(desc) > 0 and len(desc[0]) == 0:
+    desc = desc[1:]
+
+  return (
+    commit.split(' ')[1],
+    title.strip(),
+    desc)
+
+def sanitized_split(line, split_atom='\n'):
+  return list(filter(lambda x: len(x) > 0, map(lambda x: x.strip(), line.split(split_atom))))
+
+RDIFF_UPDATE_GOLDEN_STR = 'RDIFF_UPDATE_GOLDEN'
+
+if __name__ == "__main__":
+  RE_STR = f'{RDIFF_UPDATE_GOLDEN_STR}(?:S)?=[\[]?([a-zA-Z0-9,\s]+)[\]]?'
+
+  to_update = []
+  commit, title, description = get_last_commit()
+  for line in description:
+    m = re.match(RE_STR, line)
+    if not m:
+      continue
+
+    to_update += sanitize_split(m.group(1).replace(',', ' '), ' ')
+  print(','.join(to_update))