Added fallbacks for old valid channel/group name checks.

Internal methods are used by channel layers, so restore and deprecate
in order to allow updating.

Author: carltongibson

CHANGELOG.txt

@@ -1,6 +1,14 @@
 Full release notes, with more details and upgrade information, are available at:
 https://channels.readthedocs.io/en/latest/releases
 
+UNRELEASED
+----------
+
+* Added fallbacks for old valid channel/group name checks.
+
+  These were renamed in 4.2.1 but (as internal methods) without deprecation.
+  They are restored (and deprecated) here to allow updating channel layers
+  using them.
 
 4.2.1 (2025-03-29)
 ------------------

channels/layers.py

@@ -4,6 +4,7 @@
 import re
 import string
 import time
+import warnings
 from copy import deepcopy
 
 from django.conf import settings
@@ -205,6 +206,32 @@ async def group_discard(self, group, channel):
     async def group_send(self, group, message):
         raise NotImplementedError("group_send() not implemented (groups extension)")
 
+    # Deprecated methods.
+    def valid_channel_name(self, channel_name, receive=False):
+        """
+        Deprecated: Use require_valid_channel_name instead.
+
+        Checks if a channel name is valid and returns it if it is.
+        """
+        warnings.warn(
+            "valid_channel_name is deprecated, use require_valid_channel_name instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        return self.require_valid_channel_name(channel_name)
+
+    def valid_group_name(self, group_name):
+        """
+        Deprecated: Use require_valid_group_name instead.
+
+        Checks if a group name is valid and returns it if it is.
+        """
+        warnings.warn(
+            "valid_group_name is deprecated, use require_valid_group_name instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        return self.require_valid_group_name(group_name)
 
 class InMemoryChannelLayer(BaseChannelLayer):
     """

tests/test_layers.py

@@ -123,3 +123,37 @@ def test_channel_name_length_error_message(name):
 
     with pytest.raises(TypeError, match=expected_error_message):
         layer.require_valid_channel_name(name)
+
+
+def test_deprecated_valid_channel_name():
+    """
+    Test that the deprecated valid_channel_name method works
+    but raises a deprecation warning.
+    """
+    layer = BaseChannelLayer()
+
+    # Should work with valid name but raise warning
+    with pytest.warns(DeprecationWarning, match="valid_channel_name is deprecated"):
+        assert layer.valid_channel_name("valid-channel")
+
+    # Should raise TypeError for invalid names
+    with pytest.warns(DeprecationWarning):
+        with pytest.raises(TypeError):
+            layer.valid_channel_name("¯\\_(ツ)_/¯")
+
+
+def test_deprecated_valid_group_name():
+    """
+    Test that the deprecated valid_group_name method works
+    but raises a deprecation warning.
+    """
+    layer = BaseChannelLayer()
+
+    # Should work with valid name but raise warning
+    with pytest.warns(DeprecationWarning, match="valid_group_name is deprecated"):
+        assert layer.valid_group_name("valid-group")
+
+    # Should raise TypeError for invalid names
+    with pytest.warns(DeprecationWarning):
+        with pytest.raises(TypeError):
+            layer.valid_group_name("¯\\_(ツ)_/¯")