From b29445a196da78a4e98b5046a6ddb8058f0677ee Mon Sep 17 00:00:00 2001
From: Martin Desrumaux <martin.desrumaux@ircam.fr>
Date: Fri, 28 Feb 2020 17:45:40 +0100
Subject: [PATCH] feat(openapi/operationId): Warn user about duplicate
 operationId in the schema

---
 rest_framework/schemas/openapi.py | 28 ++++++++++++++++++++++++++++
 tests/schemas/test_openapi.py     | 19 +++++++++++++++++++
 tests/schemas/views.py            | 30 ++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)

diff --git a/rest_framework/schemas/openapi.py b/rest_framework/schemas/openapi.py
index 5277f17a6..ceec4517e 100644
--- a/rest_framework/schemas/openapi.py
+++ b/rest_framework/schemas/openapi.py
@@ -34,6 +34,32 @@ class SchemaGenerator(BaseSchemaGenerator):
 
         return info
 
+    def check_duplicate_operation_id(self, paths):
+        ids = {}
+        for route in paths:
+            for method in paths[route]:
+                if 'operationId' not in paths[route][method]:
+                    continue
+                operation_id = paths[route][method]['operationId']
+                if operation_id in ids:
+                    warnings.warn(
+                        'You have a duplicated operationId in your OpenAPI schema: {operation_id}\n'
+                        '\tRoute: {route1}, Method: {method1}\n'
+                        '\tRoute: {route2}, Method: {method2}\n'
+                        '\tAn operationId has to be unique accros your schema. Your schema may not work in other tools.'
+                        .format(
+                            route1=ids[operation_id]['route'],
+                            method1=ids[operation_id]['method'],
+                            route2=route,
+                            method2=method,
+                            operation_id=operation_id
+                        )
+                    )
+                ids[operation_id] = {
+                    'route': route,
+                    'method': method
+                }
+
     def get_schema(self, request=None, public=False):
         """
         Generate a OpenAPI schema.
@@ -57,6 +83,8 @@ class SchemaGenerator(BaseSchemaGenerator):
             paths.setdefault(path, {})
             paths[path][method.lower()] = operation
 
+        self.check_duplicate_operation_id(paths)
+
         # Compile final schema.
         schema = {
             'openapi': '3.0.2',
diff --git a/tests/schemas/test_openapi.py b/tests/schemas/test_openapi.py
index 7f73c8c30..9ce281d9a 100644
--- a/tests/schemas/test_openapi.py
+++ b/tests/schemas/test_openapi.py
@@ -1,4 +1,5 @@
 import uuid
+import warnings
 
 import pytest
 from django.conf.urls import url
@@ -592,6 +593,24 @@ class TestOperationIntrospection(TestCase):
         assert schema_str.count("newExample") == 1
         assert schema_str.count("oldExample") == 1
 
+    def test_duplicate_operation_id(self):
+        patterns = [
+            url(r'^duplicate1/?$', views.ExampleOperationIdDuplicate1.as_view()),
+            url(r'^duplicate2/?$', views.ExampleOperationIdDuplicate2.as_view()),
+        ]
+
+        generator = SchemaGenerator(patterns=patterns)
+        request = create_request('/')
+
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter('always')
+            generator.get_schema(request=request)
+
+            assert len(w) == 1
+            assert issubclass(w[-1].category, UserWarning)
+            print(str(w[-1].message))
+            assert 'You have a duplicated operationId' in str(w[-1].message)
+
     def test_serializer_datefield(self):
         path = '/'
         method = 'GET'
diff --git a/tests/schemas/views.py b/tests/schemas/views.py
index e8307ccbd..5835a5572 100644
--- a/tests/schemas/views.py
+++ b/tests/schemas/views.py
@@ -4,6 +4,7 @@ from django.core.validators import (
     DecimalValidator, MaxLengthValidator, MaxValueValidator,
     MinLengthValidator, MinValueValidator, RegexValidator
 )
+from django.db import models
 
 from rest_framework import generics, permissions, serializers
 from rest_framework.decorators import action
@@ -137,3 +138,32 @@ class ExampleValidatedAPIView(generics.GenericAPIView):
                                          url='http://localhost', uuid=uuid.uuid4(), ip4='127.0.0.1', ip6='::1',
                                          ip='192.168.1.1')
         return Response(serializer.data)
+
+
+# Serializer with model.
+class OpenAPIExample(models.Model):
+    first_name = models.CharField(max_length=30)
+
+
+class ExampleSerializerModel(serializers.Serializer):
+    date = serializers.DateField()
+    datetime = serializers.DateTimeField()
+    hstore = serializers.HStoreField()
+    uuid_field = serializers.UUIDField(default=uuid.uuid4)
+
+    class Meta:
+        model = OpenAPIExample
+
+
+class ExampleOperationIdDuplicate1(generics.GenericAPIView):
+    serializer_class = ExampleSerializerModel
+
+    def get(self, *args, **kwargs):
+        pass
+
+
+class ExampleOperationIdDuplicate2(generics.GenericAPIView):
+    serializer_class = ExampleSerializerModel
+
+    def get(self, *args, **kwargs):
+        pass