From 1a704c1b69d3976ed0fb94346f758c18b855a8a5 Mon Sep 17 00:00:00 2001
From: Jonathan de Jong <jonathan@automatia.nl>
Date: Mon, 5 Apr 2021 17:10:55 +0200
Subject: [PATCH 1/5] synapse/crypto

---
 synapse/crypto/__init__.py      |  1 -
 synapse/crypto/event_signing.py |  7 +++----
 synapse/crypto/keyring.py       | 11 +++++------
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/synapse/crypto/__init__.py b/synapse/crypto/__init__.py
index bfebb0f644f4..5e83dba2ed6f 100644
--- a/synapse/crypto/__init__.py
+++ b/synapse/crypto/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py
index 8fb116ae182c..2822fc338a60 100644
--- a/synapse/crypto/event_signing.py
+++ b/synapse/crypto/event_signing.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2020 The Matrix.org Foundation C.I.C.
@@ -53,13 +52,13 @@ def check_event_content_hash(
     # nb it might be a frozendict or a dict
     if not isinstance(hashes, collections.abc.Mapping):
         raise SynapseError(
-            400, "Malformed 'hashes': %s" % (type(hashes),), Codes.UNAUTHORIZED
+            400, "Malformed 'hashes': {}".format(type(hashes)), Codes.UNAUTHORIZED
         )
 
     if name not in hashes:
         raise SynapseError(
             400,
-            "Algorithm %s not in hashes %s" % (name, list(hashes)),
+            "Algorithm {} not in hashes {}".format(name, list(hashes)),
             Codes.UNAUTHORIZED,
         )
     message_hash_base64 = hashes[name]
@@ -67,7 +66,7 @@ def check_event_content_hash(
         message_hash_bytes = decode_base64(message_hash_base64)
     except Exception:
         raise SynapseError(
-            400, "Invalid base64: %s" % (message_hash_base64,), Codes.UNAUTHORIZED
+            400, f"Invalid base64: {message_hash_base64}", Codes.UNAUTHORIZED
         )
     return message_hash_bytes == expected_hash
 
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index d5fb51513b59..25148682635e 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2017, 2018 New Vector Ltd
 #
@@ -209,7 +208,7 @@ def process(verify_request: VerifyJsonRequest) -> defer.Deferred:
                 return defer.fail(
                     SynapseError(
                         400,
-                        "Not signed by %s" % (verify_request.server_name,),
+                        f"Not signed by {verify_request.server_name}",
                         Codes.UNAUTHORIZED,
                     )
                 )
@@ -319,7 +318,7 @@ async def wait_for_previous_lookups(self, server_names: Iterable[str]) -> None:
                 loop_count,
             )
             with PreserveLoggingContext():
-                await defer.DeferredList((w[1] for w in wait_on))
+                await defer.DeferredList(w[1] for w in wait_on)
 
             loop_count += 1
 
@@ -369,7 +368,7 @@ async def do_iterations():
                             verify_request.key_ready.errback,
                             SynapseError(
                                 401,
-                                "Failed to find any key to satisfy %s" % (rq_str,),
+                                f"Failed to find any key to satisfy {rq_str}",
                                 Codes.UNAUTHORIZED,
                             ),
                         )
@@ -688,7 +687,7 @@ async def get_server_verify_key_v2_indirect(
             # these both have str() representations which we can't really improve upon
             raise KeyLookupError(str(e))
         except HttpResponseException as e:
-            raise KeyLookupError("Remote server returned an error: %s" % (e,))
+            raise KeyLookupError(f"Remote server returned an error: {e}")
 
         keys = {}  # type: Dict[str, Dict[str, FetchKeyResult]]
         added_keys = []  # type: List[Tuple[str, str, FetchKeyResult]]
@@ -856,7 +855,7 @@ async def get_server_verify_key_v2_direct(
                 # upon
                 raise KeyLookupError(str(e))
             except HttpResponseException as e:
-                raise KeyLookupError("Remote server returned an error: %s" % (e,))
+                raise KeyLookupError(f"Remote server returned an error: {e}")
 
             assert isinstance(response, dict)
             if response["server_name"] != server_name:

From 23a2693264902f22777e1c04f5b3738a7f77f4c4 Mon Sep 17 00:00:00 2001
From: Jonathan de Jong <jonathan@automatia.nl>
Date: Mon, 5 Apr 2021 17:12:12 +0200
Subject: [PATCH 2/5] synapse/events

---
 synapse/events/__init__.py          | 13 ++++++-------
 synapse/events/builder.py           |  3 +--
 synapse/events/snapshot.py          |  1 -
 synapse/events/spamcheck.py         |  1 -
 synapse/events/third_party_rules.py |  1 -
 synapse/events/utils.py             |  9 +++------
 synapse/events/validator.py         | 13 ++++++-------
 7 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index 8f6b955d17b7..e251205afc31 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2019 New Vector Ltd
 # Copyright 2020 The Matrix.org Foundation C.I.C.
@@ -63,7 +62,7 @@ def __get__(self, instance, owner=None):
             # because that would omit any *earlier* exceptions).
             #
             raise AttributeError(
-                "'%s' has no '%s' property" % (type(instance), self.key)
+                "'{}' has no '{}' property".format(type(instance), self.key)
             ) from e1.__context__
 
     def __set__(self, instance, v):
@@ -74,7 +73,7 @@ def __delete__(self, instance):
             del instance._dict[self.key]
         except KeyError as e1:
             raise AttributeError(
-                "'%s' has no '%s' property" % (type(instance), self.key)
+                "'{}' has no '{}' property".format(type(instance), self.key)
             ) from e1.__context__
 
 
@@ -284,7 +283,7 @@ def get_pdu_json(self, time_now=None) -> JsonDict:
         return pdu_json
 
     def __set__(self, instance, value):
-        raise AttributeError("Unrecognized attribute %s" % (instance,))
+        raise AttributeError(f"Unrecognized attribute {instance}")
 
     def __getitem__(self, field):
         return self._dict[field]
@@ -372,7 +371,7 @@ def __str__(self):
         return self.__repr__()
 
     def __repr__(self):
-        return "<FrozenEvent event_id=%r, type=%r, state_key=%r>" % (
+        return "<FrozenEvent event_id={!r}, type={!r}, state_key={!r}>".format(
             self.get("event_id", None),
             self.get("type", None),
             self.get("state_key", None),
@@ -455,7 +454,7 @@ def __str__(self):
         return self.__repr__()
 
     def __repr__(self):
-        return "<%s event_id=%r, type=%r, state_key=%r>" % (
+        return "<{} event_id={!r}, type={!r}, state_key={!r}>".format(
             self.__class__.__name__,
             self.event_id,
             self.get("type", None),
@@ -501,7 +500,7 @@ def _event_type_from_format_version(format_version: int) -> Type[EventBase]:
     elif format_version == EventFormatVersions.V3:
         return FrozenEventV3
     else:
-        raise Exception("No event format %r" % (format_version,))
+        raise Exception(f"No event format {format_version!r}")
 
 
 def make_event_from_dict(
diff --git a/synapse/events/builder.py b/synapse/events/builder.py
index c1c0426f6ea0..4e6e2f656062 100644
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -245,7 +244,7 @@ def create_local_event_from_event_dict(
 
     format_version = room_version.event_format
     if format_version not in KNOWN_EVENT_FORMAT_VERSIONS:
-        raise Exception("No event format defined for version %r" % (format_version,))
+        raise Exception(f"No event format defined for version {format_version!r}")
 
     if internal_metadata_dict is None:
         internal_metadata_dict = {}
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index 7295df74fed6..f8d898c3b1d1 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/events/spamcheck.py b/synapse/events/spamcheck.py
index a9185987a237..c727b48c1ef5 100644
--- a/synapse/events/spamcheck.py
+++ b/synapse/events/spamcheck.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2017 New Vector Ltd
 # Copyright 2019 The Matrix.org Foundation C.I.C.
 #
diff --git a/synapse/events/third_party_rules.py b/synapse/events/third_party_rules.py
index 9767d2394050..f7944fd8344f 100644
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2019 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 0f8a3b5ad839..89768b71c6e1 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -453,7 +452,7 @@ def copy_power_levels_contents(
         TypeError if the input does not look like a valid power levels event content
     """
     if not isinstance(old_power_levels, collections.abc.Mapping):
-        raise TypeError("Not a valid power-levels content: %r" % (old_power_levels,))
+        raise TypeError(f"Not a valid power-levels content: {old_power_levels!r}")
 
     power_levels = {}
     for k, v in old_power_levels.items():
@@ -467,13 +466,11 @@ def copy_power_levels_contents(
             for k1, v1 in v.items():
                 # we should only have one level of nesting
                 if not isinstance(v1, int):
-                    raise TypeError(
-                        "Invalid power_levels value for %s.%s: %r" % (k, k1, v1)
-                    )
+                    raise TypeError(f"Invalid power_levels value for {k}.{k1}: {v1!r}")
                 h[k1] = v1
             continue
 
-        raise TypeError("Invalid power_levels value for %s: %r" % (k, v))
+        raise TypeError(f"Invalid power_levels value for {k}: {v!r}")
 
     return power_levels
 
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index f8f3b1a31e0b..aeea35c6a034 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -51,14 +50,14 @@ def validate_new(self, event: EventBase, config: HomeServerConfig):
 
         for k in required:
             if not hasattr(event, k):
-                raise SynapseError(400, "Event does not have key %s" % (k,))
+                raise SynapseError(400, f"Event does not have key {k}")
 
         # Check that the following keys have string values
         event_strings = ["origin"]
 
         for s in event_strings:
             if not isinstance(getattr(event, s), str):
-                raise SynapseError(400, "'%s' not a string type" % (s,))
+                raise SynapseError(400, f"'{s}' not a string type")
 
         # Depending on the room version, ensure the data is spec compliant JSON.
         if event.room_version.strict_canonicaljson:
@@ -141,7 +140,7 @@ def validate_builder(self, event: Union[EventBase, EventBuilder]):
 
         for s in strings:
             if not isinstance(getattr(event, s), str):
-                raise SynapseError(400, "Not '%s' a string type" % (s,))
+                raise SynapseError(400, f"Not '{s}' a string type")
 
         RoomID.from_string(event.room_id)
         UserID.from_string(event.sender)
@@ -179,10 +178,10 @@ def validate_builder(self, event: Union[EventBase, EventBuilder]):
     def _ensure_strings(self, d, keys):
         for s in keys:
             if s not in d:
-                raise SynapseError(400, "'%s' not in content" % (s,))
+                raise SynapseError(400, f"'{s}' not in content")
             if not isinstance(d[s], str):
-                raise SynapseError(400, "'%s' not a string type" % (s,))
+                raise SynapseError(400, f"'{s}' not a string type")
 
     def _ensure_state_event(self, event):
         if not event.is_state():
-            raise SynapseError(400, "'%s' must be state events" % (event.type,))
+            raise SynapseError(400, f"'{event.type}' must be state events")

From 024c074da128215ce59333fd76d246da396971bb Mon Sep 17 00:00:00 2001
From: Jonathan de Jong <jonathan@automatia.nl>
Date: Mon, 5 Apr 2021 17:13:40 +0200
Subject: [PATCH 3/5] synapse/federation

---
 synapse/federation/__init__.py                     | 1 -
 synapse/federation/federation_base.py              | 5 ++---
 synapse/federation/federation_client.py            | 3 +--
 synapse/federation/federation_server.py            | 9 ++++-----
 synapse/federation/persistence.py                  | 1 -
 synapse/federation/send_queue.py                   | 3 +--
 synapse/federation/sender/__init__.py              | 1 -
 synapse/federation/sender/per_destination_queue.py | 1 -
 synapse/federation/sender/transaction_manager.py   | 1 -
 synapse/federation/transport/__init__.py           | 1 -
 synapse/federation/transport/client.py             | 1 -
 synapse/federation/transport/server.py             | 1 -
 synapse/federation/units.py                        | 1 -
 13 files changed, 8 insertions(+), 21 deletions(-)

diff --git a/synapse/federation/__init__.py b/synapse/federation/__init__.py
index f5f0bdfca3ec..46300cba2564 100644
--- a/synapse/federation/__init__.py
+++ b/synapse/federation/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 383737520afa..04997f224361 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
 # Copyright 2020 The Matrix.org Foundation C.I.C.
 #
@@ -209,7 +208,7 @@ def _check_sigs_on_pdus(
     )
 
     def sender_err(e, pdu_to_check):
-        errmsg = "event id %s: unable to verify signature for sender %s: %s" % (
+        errmsg = "event id {}: unable to verify signature for sender {}: {}".format(
             pdu_to_check.pdu.event_id,
             pdu_to_check.sender_domain,
             e.getErrorMessage(),
@@ -298,7 +297,7 @@ def event_from_pdu_json(
 
     depth = pdu_json["depth"]
     if not isinstance(depth, int):
-        raise SynapseError(400, "Depth %r not an intger" % (depth,), Codes.BAD_JSON)
+        raise SynapseError(400, f"Depth {depth!r} not an intger", Codes.BAD_JSON)
 
     if depth < 0:
         raise SynapseError(400, "Depth too small", Codes.BAD_JSON)
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index afdb5bf2fafb..100ef60469b6 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -530,7 +529,7 @@ async def _try_destination_list(
                     "Failed to %s via %s", description, destination, exc_info=True
                 )
 
-        raise SynapseError(502, "Failed to %s via any server" % (description,))
+        raise SynapseError(502, f"Failed to {description} via any server")
 
     async def make_membership_event(
         self,
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 71cb120ef76b..7661d232b4da 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
 # Copyright 2018 New Vector Ltd
 # Copyright 2019 Matrix.org Federation C.I.C
@@ -636,7 +635,7 @@ async def on_claim_client_keys(
             "Claimed one-time-keys: %s",
             ",".join(
                 (
-                    "%s for %s:%s" % (key_id, user_id, device_id)
+                    f"{key_id} for {user_id}:{device_id}"
                     for user_id, user_keys in json_result.items()
                     for device_id, device_keys in user_keys.items()
                     for key_id, _ in device_keys.items()
@@ -889,7 +888,7 @@ def register_edu_handler(
                 the EDU contents.
         """
         if edu_type in self.edu_handlers:
-            raise KeyError("Already have an EDU handler for %s" % (edu_type,))
+            raise KeyError(f"Already have an EDU handler for {edu_type}")
 
         logger.info("Registering federation EDU handler for %r", edu_type)
 
@@ -909,7 +908,7 @@ def register_query_handler(
                 on and the result used as the response to the query request.
         """
         if query_type in self.query_handlers:
-            raise KeyError("Already have a Query handler for %s" % (query_type,))
+            raise KeyError(f"Already have a Query handler for {query_type}")
 
         logger.info("Registering federation query handler for %r", query_type)
 
@@ -983,4 +982,4 @@ async def on_query(self, query_type: str, args: dict) -> JsonDict:
         # Uh oh, no handler! Let's raise an exception so the request returns an
         # error.
         logger.warning("No handler registered for query type %s", query_type)
-        raise NotFoundError("No handler for Query type '%s'" % (query_type,))
+        raise NotFoundError(f"No handler for Query type '{query_type}'")
diff --git a/synapse/federation/persistence.py b/synapse/federation/persistence.py
index ce5fc758f0e6..2f9c9bc2cdc8 100644
--- a/synapse/federation/persistence.py
+++ b/synapse/federation/persistence.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 0c18c49abb70..83d99665232a 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -110,7 +109,7 @@ def __init__(self, hs: "HomeServer"):
         # changes. ARGH.
         def register(name: str, queue: Sized) -> None:
             LaterGauge(
-                "synapse_federation_send_queue_%s_size" % (queue_name,),
+                f"synapse_federation_send_queue_{queue_name}_size",
                 "",
                 [],
                 lambda: len(queue),
diff --git a/synapse/federation/sender/__init__.py b/synapse/federation/sender/__init__.py
index 8babb1ebbe4e..d4a71ac43279 100644
--- a/synapse/federation/sender/__init__.py
+++ b/synapse/federation/sender/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2019 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/federation/sender/per_destination_queue.py b/synapse/federation/sender/per_destination_queue.py
index e9c8a9f20a66..3b053ebcfb08 100644
--- a/synapse/federation/sender/per_destination_queue.py
+++ b/synapse/federation/sender/per_destination_queue.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2019 New Vector Ltd
 #
diff --git a/synapse/federation/sender/transaction_manager.py b/synapse/federation/sender/transaction_manager.py
index 07b740c2f2fc..12fe3a719bc3 100644
--- a/synapse/federation/sender/transaction_manager.py
+++ b/synapse/federation/sender/transaction_manager.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2019 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/federation/transport/__init__.py b/synapse/federation/transport/__init__.py
index 5db733af98ca..3c9a0f694482 100644
--- a/synapse/federation/transport/__init__.py
+++ b/synapse/federation/transport/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 6aee47c43116..ada322a81e14 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2018 New Vector Ltd
 #
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 84e39c5a468d..b65e5e66d0f5 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2018 New Vector Ltd
 # Copyright 2019 The Matrix.org Foundation C.I.C.
diff --git a/synapse/federation/units.py b/synapse/federation/units.py
index b662c4262120..3eb236d11908 100644
--- a/synapse/federation/units.py
+++ b/synapse/federation/units.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");

From 6d1edb487203fc2ba57963a8326f65ff3a4ed7bc Mon Sep 17 00:00:00 2001
From: Jonathan de Jong <jonathan@automatia.nl>
Date: Mon, 5 Apr 2021 17:14:24 +0200
Subject: [PATCH 4/5] synapse/groups

---
 synapse/groups/attestations.py  | 1 -
 synapse/groups/groups_server.py | 5 ++---
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py
index 368c44708dac..d2fc8be5f571 100644
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2017 Vector Creations Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/synapse/groups/groups_server.py b/synapse/groups/groups_server.py
index 4b16a4ac29ea..897cf71679e5 100644
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright 2017 Vector Creations Ltd
 # Copyright 2018 New Vector Ltd
 # Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
@@ -554,13 +553,13 @@ async def update_group_profile(
                 if not isinstance(value, str):
                     raise SynapseError(
                         400,
-                        "%r value is not a string" % (keyname,),
+                        f"{keyname!r} value is not a string",
                         errcode=Codes.INVALID_PARAM,
                     )
                 if len(value) > max_length:
                     raise SynapseError(
                         400,
-                        "Invalid %s parameter" % (keyname,),
+                        f"Invalid {keyname} parameter",
                         errcode=Codes.INVALID_PARAM,
                     )
                 profile[keyname] = value

From 89fc4acb2af91fed2302e4f2089ca1fa0e305753 Mon Sep 17 00:00:00 2001
From: Jonathan de Jong <jonathan@automatia.nl>
Date: Mon, 5 Apr 2021 18:15:01 +0200
Subject: [PATCH 5/5] news

---
 changelog.d/9749.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/9749.misc

diff --git a/changelog.d/9749.misc b/changelog.d/9749.misc
new file mode 100644
index 000000000000..7140799fdab7
--- /dev/null
+++ b/changelog.d/9749.misc
@@ -0,0 +1 @@
+Run `pyupgrade --py36-plus` over the codebase.
\ No newline at end of file