fix 'first-match-wins' bug and test it

Signed-off-by: Venky Ganesh <[email protected]>

Author: venkywonka

.github/scripts/assign_reviewers.py

@@ -68,19 +68,31 @@ def load_json(path: str):
 
 def map_modules(changed_files: list[str],
                 module_paths: dict[str, str]) -> tuple[set[str], list[str]]:
-    """Map changed files to modules and return both modules and unmapped files"""
+    """Map changed files to modules using MOST SPECIFIC (longest) prefix match"""
     modules: set[str] = set()
     unmapped_files: list[str] = []
 
     for file in changed_files:
-        mapped = False
+        # Find ALL matching prefixes
+        matches = []
         for prefix, module in module_paths.items():
             if file.startswith(prefix):
-                modules.add(module)
-                mapped = True
-                break
-
-        if not mapped:
+                matches.append((len(prefix), prefix, module))
+
+        if matches:
+            # Sort by prefix length (descending) to get most specific first
+            matches.sort(reverse=True)
+            most_specific_module = matches[0][2]
+            modules.add(most_specific_module)
+
+            # Log if there were multiple matches (for debugging)
+            if len(matches) > 1:
+                matches[0][1]
+                print(f"  File '{file}' has overlapping mappings:")
+                for _, prefix, module in matches:
+                    marker = "→" if module == most_specific_module else " "
+                    print(f"    {marker} {prefix} -> {module}")
+        else:
             unmapped_files.append(file)
 
     return modules, unmapped_files

.github/scripts/tests/test_assign_reviewers.py

@@ -386,6 +386,38 @@ def test_all_files_unmapped(self):
         self.assertEqual(set(unmapped_files),
                          {"unmapped/file1.txt", "another/file2.py"})
 
+    def test_most_specific_module_mapping(self):
+        """Test that files map to the most specific module match"""
+        # Create overlapping module paths similar to the real config
+        overlapping_paths = {
+            "tensorrt_llm/": "LLM API/Workflow",
+            "tensorrt_llm/_torch/": "Torch Framework",
+            "tensorrt_llm/_torch/models/": "Torch Models",
+            "tensorrt_llm/_torch/models/modeling_llama.py":
+            "Torch Models Llama",
+            "tests/": "General Tests",
+            "tests/integration/": "Integration Tests",
+            "tests/integration/test_lists/": "Test Configuration",
+        }
+
+        # Test individual files mapping to most specific modules
+        test_cases = [
+            ("tensorrt_llm/api.py", "LLM API/Workflow"),
+            ("tensorrt_llm/_torch/utils.py", "Torch Framework"),
+            ("tensorrt_llm/_torch/models/bert.py", "Torch Models"),
+            ("tensorrt_llm/_torch/models/modeling_llama.py",
+             "Torch Models Llama"),
+            ("tests/unit_test.py", "General Tests"),
+            ("tests/integration/test_x.py", "Integration Tests"),
+            ("tests/integration/test_lists/config.json", "Test Configuration"),
+        ]
+
+        for file, expected_module in test_cases:
+            modules, _ = assign_reviewers.map_modules([file], overlapping_paths)
+            self.assertEqual(
+                modules, {expected_module},
+                f"File '{file}' should map to '{expected_module}'")
+
     @patch('assign_reviewers.load_json')
     @patch('subprocess.run')
     def test_module_with_no_owners(self, mock_run, mock_load_json):