Fix deprecation warning: import ABC from collections.abc (#7892)

changelog.d/7892.misc

@@ -0,0 +1 @@
+Import ABC from `collections.abc` for Python 3.10 compatibility.

synapse/events/utils.py

@@ -12,7 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import collections
+import collections.abc
 import re
 from typing import Any, Mapping, Union
 
@@ -424,7 +424,7 @@ def copy_power_levels_contents(
     Raises:
         TypeError if the input does not look like a valid power levels event content
     """
-    if not isinstance(old_power_levels, collections.Mapping):
+    if not isinstance(old_power_levels, collections.abc.Mapping):
         raise TypeError("Not a valid power-levels content: %r" % (old_power_levels,))
 
     power_levels = {}
@@ -434,7 +434,7 @@ def copy_power_levels_contents(
             power_levels[k] = v
             continue
 
-        if isinstance(v, collections.Mapping):
+        if isinstance(v, collections.abc.Mapping):
             power_levels[k] = h = {}
             for k1, v1 in v.items():
                 # we should only have one level of nesting

synapse/handlers/federation.py

@@ -19,7 +19,7 @@
 
 import itertools
 import logging
-from collections import Container
+from collections.abc import Container
 from http import HTTPStatus
 from typing import Dict, Iterable, List, Optional, Sequence, Tuple, Union
 

synapse/replication/tcp/streams/events.py

@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import heapq
-from collections import Iterable
+from collections.abc import Iterable
 from typing import List, Tuple, Type
 
 import attr

synapse/util/stringutils.py

@@ -17,7 +17,7 @@
 import random
 import re
 import string
-from collections import Iterable
+from collections.abc import Iterable
 
 from synapse.api.errors import Codes, SynapseError