Deprecate ResponseTypes itself

scrapy/responsetypes.py

@@ -2,7 +2,7 @@
 This module implements a class which returns the appropriate Response class
 based on different criteria.
 """
-from warnings import warn
+from warnings import catch_warnings, simplefilter, warn
 
 from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.http import Response
@@ -30,6 +30,17 @@ class ResponseTypes:
         'text/*': 'scrapy.http.TextResponse',
     }
 
+    def __new__(cls, *args, **kwargs):
+        warn(
+            (
+                'scrapy.responsetypes.ResponseTypes is deprecated, use '
+                'scrapy.utils.response.get_response_class instead'
+            ),
+            ScrapyDeprecationWarning,
+            stacklevel=2,
+        )
+        return super().__new__(cls)
+
     def __init__(self):
         self.classes = {}
         self.mimetypes = _MIME_TYPES
@@ -131,4 +142,6 @@ class ResponseTypes:
         return cls
 
 
-responsetypes = ResponseTypes()
+with catch_warnings():
+    simplefilter("ignore")
+    responsetypes = ResponseTypes()

tests/test_responsetypes.py

@@ -1,4 +1,5 @@
 import unittest
+from warnings import catch_warnings
 
 import pytest
 
@@ -9,7 +10,7 @@ from scrapy.http import (
     TextResponse,
     XmlResponse,
 )
-from scrapy.responsetypes import responsetypes
+from scrapy.responsetypes import responsetypes, ResponseTypes
 from .test_utils_response import (
     POST_XTRACTMIME_SCENARIOS,
     PRE_XTRACTMIME_SCENARIOS,
@@ -116,6 +117,16 @@ class ResponseTypesTest(unittest.TestCase):
         # check that mime.types files shipped with scrapy are loaded
         self.assertEqual(responsetypes.mimetypes.guess_type('x.scrapytest')[0], 'x-scrapy/test')
 
+    def test_class_deprecation(self):
+        with catch_warnings(record=True) as warnings:
+            ResponseTypes()
+        expected_message = (
+            'scrapy.responsetypes.ResponseTypes is deprecated, use '
+            'scrapy.utils.response.get_response_class instead'
+        )
+        messages = {str(warning.message) for warning in warnings}
+        self.assertIn(expected_message, messages)
+
 
 if __name__ == "__main__":
     unittest.main()