chore: fix spanner fallback and add test for split_release_note (#12896)

The original code assumed that if `.OwlBot-hermetic.yaml` existed, it
must contain an `api-name`. This is not true for Spanner, which has the
file but lacks the `api-name field`. So, fallback to
`.repo-metadata.json` is needed sometimes even if
`.OwlBot-hermetic.yaml` exists.

Towards #12864.

Author: meltsufin

.github/release-note-generation/split_release_note.py

@@ -69,6 +69,7 @@ def detect_modules(root_directory: Path):
         tree = ET.parse(module_pom_xml)
         root = tree.getroot()
         version = root.find('mvn:version', POM_NAMESPACES).text
+        api_name = None
         if owlbot_yaml_path.exists():
             # If OwlBot configuration file exists (most cases), it's the better
             # source to get the OwlBot-generated pull request title prefix than
@@ -78,21 +79,21 @@ def detect_modules(root_directory: Path):
                 match = re.search(r'api-name: (.+)', owlbot_yaml_content)
                 if match:
                     api_name = match.group(1)
-                    modules.append(LibraryModule(module_path, api_name,
-                                                 version,
-                                                 changelog))
+
+        if not api_name:
+            # Fallback to repo-metadata.json (e.g. for vertexai or Spanner transitional state)
+            if repo_metadata_path.exists():
+                with open(repo_metadata_path, 'r') as file:
+                    repo_metadata = json.load(file)
+                    api_name = repo_metadata.get('api_shortname')
+
+        if api_name:
+            modules.append(LibraryModule(module_path, api_name,
+                                         version,
+                                         changelog))
         else:
-            # vertexai (handwritten) does not have OwlBot yaml file
-            with open(repo_metadata_path, 'r') as file:
-                repo_metadata = json.load(file)
-                api_name = repo_metadata['api_shortname']
-                if api_name:
-                    modules.append(LibraryModule(repo_metadata_path.parent, api_name,
-                                                 version,
-                                                 changelog))
-                else:
-                    raise Exception(f'repo_metadata_path {repo_metadata_path} does'
-                                    f' not have api_shortname field')
+            raise Exception(f'Could not determine api-name for {repo_metadata_path}')
+
 
     return modules
 
@@ -133,7 +134,7 @@ def group_changes_by_api(main_changes: [str]):
             elif section == BUG_FIXES_SECTION:
                 api_to_changelog[api_name].bug_fixes.append(note)
             elif section == DEPENDENCIES_SECTION:
-                api_to_changelog[api_name].dependencies.append(note)
+                api_to_changelog[api_name].dependency_upgrades.append(note)
     return api_to_changelog
 
 

.github/release-note-generation/unit_test.py

@@ -1,9 +1,11 @@
 import unittest
+import tempfile
+import json
+from pathlib import Path
 
 # Unit tests for split_release_note.py
 
-from split_release_note import LibraryModule, create_changelog_entry, group_changes_by_api, ChangesOnApi
-from pathlib import Path
+from split_release_note import LibraryModule, create_changelog_entry, group_changes_by_api, ChangesOnApi, detect_modules
 
 dummy_module = LibraryModule(
     Path('release-note-generation/test/java-analyics-admin'),
@@ -81,6 +83,31 @@ def test_group_changes_by_api(self):
                                      ['No change']),
                          ['No change'])
 
+    def test_detect_modules_fallback(self):
+        with tempfile.TemporaryDirectory() as tmpdirname:
+            tmp_path = Path(tmpdirname)
+            module_path = tmp_path / "java-spanner"
+            module_path.mkdir()
+            
+            # Create minimal pom.xml
+            pom_path = module_path / "pom.xml"
+            with open(pom_path, "w") as f:
+                f.write('<project xmlns:mvn="http://maven.apache.org/POM/4.0.0"><mvn:version>1.0.0</mvn:version></project>')
+                
+            # Create .repo-metadata.json with api_shortname
+            metadata_path = module_path / ".repo-metadata.json"
+            with open(metadata_path, "w") as f:
+                json.dump({"api_shortname": "spanner"}, f)
+                
+            # Create CHANGELOG.md
+            changelog_path = module_path / "CHANGELOG.md"
+            changelog_path.touch()
+            
+            modules = detect_modules(tmp_path)
+            self.assertEqual(len(modules), 1)
+            self.assertEqual(modules[0].api_name, "spanner")
+            self.assertEqual(modules[0].version, "1.0.0")
+
 
 if __name__ == "__main__":
     unittest.main()