Replace deprecation warning with RuntimeError (GH-14397)

2 files changed, 8 insertions, 4 deletions

diff --git a/Lib/asyncio/streams.py b/Lib/asyncio/streams.py
index f03441b6b1..204eaf7394 100644
--- a/Lib/asyncio/streams.py
+++ b/Lib/asyncio/streams.py
@@ -1293,10 +1293,8 @@ class Stream:
                  is_server_side=False,
                  _asyncio_internal=False):
         if not _asyncio_internal:
-            warnings.warn(f"{self.__class__} should be instaniated "
-                          "by asyncio internals only, "
-                          "please avoid its creation from user code",
-                          DeprecationWarning)
+            raise RuntimeError(f"{self.__class__} should be instantiated "
+                               "by asyncio internals only")
         self._mode = mode
         self._transport = transport
         self._protocol = protocol
diff --git a/Lib/test/test_asyncio/test_streams.py b/Lib/test/test_asyncio/test_streams.py
index a1c62ecee6..eab71e8030 100644
--- a/Lib/test/test_asyncio/test_streams.py
+++ b/Lib/test/test_asyncio/test_streams.py
@@ -1779,6 +1779,12 @@ os.close(fd)
 
         self.loop.run_until_complete(test())
 
+    def test_stream_ctor_forbidden(self):
+        with self.assertRaisesRegex(RuntimeError,
+                                    "should be instantiated "
+                                    "by asyncio internals only"):
+            asyncio.Stream(asyncio.StreamMode.READWRITE)
+
 
 if __name__ == '__main__':
     unittest.main()