Represent SafeString as plain string on schema rendering.

rest_framework/renderers.py

@@ -18,6 +18,7 @@
 from django.template import engines, loader
 from django.urls import NoReverseMatch
 from django.utils.html import mark_safe
+from django.utils.safestring import SafeString
 
 from rest_framework import VERSION, exceptions, serializers, status
 from rest_framework.compat import (
@@ -1060,6 +1061,7 @@ def render(self, data, media_type=None, renderer_context=None):
         class Dumper(yaml.Dumper):
             def ignore_aliases(self, data):
                 return True
+        Dumper.add_representer(SafeString, Dumper.represent_str)
         return yaml.dump(data, default_flow_style=False, sort_keys=False, Dumper=Dumper).encode('utf-8')
 
 

tests/schemas/test_openapi.py

@@ -5,6 +5,7 @@
 from django.db import models
 from django.test import RequestFactory, TestCase, override_settings
 from django.urls import path
+from django.utils.safestring import SafeString
 from django.utils.translation import gettext_lazy as _
 
 from rest_framework import filters, generics, pagination, routers, serializers
@@ -569,6 +570,11 @@ def test_openapi_yaml_rendering_without_aliases(self):
             renderer.render(data) == b'o2:\n  test: test\no1:\n  test: test\n'  # py <= 3.5
         )
 
+    def test_openapi_yaml_safestring_render(self):
+        renderer = OpenAPIRenderer()
+        data = {'o1': SafeString('test')}
+        assert renderer.render(data) == b'o1: test\n'
+
     def test_serializer_filefield(self):
         path = '/{id}/'
         method = 'POST'