Added verify_duplicate_sources

tools/buildgen/plugins/verify_duplicate_sources.py

@@ -0,0 +1,42 @@
+# Copyright 2020 gRPC authors.
+#
+# 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.
+"""Buildgen duplicate source validation plugin."""
+
+
+def mako_plugin(dictionary):
+    """The exported plugin code for verify_duplicate_sources.
+
+    This validates that a certain set of libraries don't contain
+    duplicate source files which may cause One Definition Rule (ODR)
+    violation.
+    """
+    errors = []
+    target_groups = (
+        ('gpr', 'grpc', 'grpc++'),
+        ('gpr', 'grpc_unsecure', 'grpc++_unsecure'),
+    )
+    lib_map = {lib['name']: lib for lib in dictionary.get('libs')}
+    for target_group in target_groups:
+        src_map = {}
+        for target in target_group:
+            for src in lib_map[target]['src']:
+                if src.endswith('.cc'):
+                    if src in src_map:
+                        errors.append(
+                            'Source {0} is used in both {1} and {2}'.format(
+                                src, src_map[src], target))
+                    else:
+                        src_map[src] = target
+    if errors:
+        raise Exception('\n'.join(errors))