Make 'event.redacts' never raise. (#6771)

* commit 'fa4d609e2':
  Make 'event.redacts' never raise. (#6771)
  Fixup changelog
  Fixup changelog
  Fixup changelog

CHANGES.md

@@ -1,15 +1,19 @@
 Synapse 1.9.0 (2020-01-23)
 ==========================
 
-No significant changes.
+**WARNING**: As of this release, Synapse no longer supports versions of SQLite before 3.11, and will refuse to start when configured to use an older version. Administrators are recommended to migrate their database to Postgres (see instructions [here](docs/postgres.md)).
 
+If your Synapse deployment uses workers, note that the reverse-proxy configurations for the `synapse.app.media_repository`, `synapse.app.federation_reader` and `synapse.app.event_creator` workers have changed, with the addition of a few paths (see the updated configurations [here](docs/workers.md#available-worker-applications)). Existing configurations will continue to work.
 
-Synapse 1.9.0rc1 (2020-01-22)
-=============================
 
-**WARNING**: As of this release, Synapse no longer supports versions of SQLite before 3.11, and will refuse to start when configured to use an older version. Administrators are recommended to migrate their database to Postgres (see instructions [here](docs/postgres.md)).
+Improved Documentation
+----------------------
+
+- Fix endpoint documentation for the List Rooms admin API. ([\#6770](https://github.com/matrix-org/synapse/issues/6770))
+
 
-If your Synapse deployment uses workers, note that the reverse-proxy configurations for the `synapse.app.media_repository`, `synapse.app.federation_reader` and `synapse.app.event_creator` have changed, with the addition of a few paths (see the updated configurations [here](docs/workers.md#available-worker-applications)).
+Synapse 1.9.0rc1 (2020-01-22)
+=============================
 
 Features
 --------

changelog.d/6771.bugfix

@@ -0,0 +1 @@
+Fix persisting redaction events that have been redacted (or otherwise don't have a redacts key).

synapse/events/__init__.py

@@ -116,16 +116,32 @@ def is_redacted(self):
         return getattr(self, "redacted", False)
 
 
-def _event_dict_property(key):
+_SENTINEL = object()
+
+
+def _event_dict_property(key, default=_SENTINEL):
+    """Creates a new property for the given key that delegates access to
+    `self._event_dict`.
+
+    The default is used if the key is missing from the `_event_dict`, if given,
+    otherwise an AttributeError will be raised.
+
+    Note: If a default is given then `hasattr` will always return true.
+    """
+
     # We want to be able to use hasattr with the event dict properties.
     # However, (on python3) hasattr expects AttributeError to be raised. Hence,
     # we need to transform the KeyError into an AttributeError
-    def getter(self):
+
+    def getter_raises(self):
         try:
             return self._event_dict[key]
         except KeyError:
             raise AttributeError(key)
 
+    def getter_default(self):
+        return self._event_dict.get(key, default)
+
     def setter(self, v):
         try:
             self._event_dict[key] = v
@@ -138,7 +154,11 @@ def delete(self):
         except KeyError:
             raise AttributeError(key)
 
-    return property(getter, setter, delete)
+    if default is _SENTINEL:
+        # No default given, so use the getter that raises
+        return property(getter_raises, setter, delete)
+    else:
+        return property(getter_default, setter, delete)
 
 
 class EventBase(object):
@@ -165,7 +185,7 @@ def __init__(
     origin = _event_dict_property("origin")
     origin_server_ts = _event_dict_property("origin_server_ts")
     prev_events = _event_dict_property("prev_events")
-    redacts = _event_dict_property("redacts")
+    redacts = _event_dict_property("redacts", None)
     room_id = _event_dict_property("room_id")
     sender = _event_dict_property("sender")
     user_id = _event_dict_property("sender")

synapse/storage/data_stores/main/events.py

@@ -951,7 +951,7 @@ def _update_metadata_tables_txn(
             elif event.type == EventTypes.Message:
                 # Insert into the event_search table.
                 self._store_room_message_txn(txn, event)
-            elif event.type == EventTypes.Redaction:
+            elif event.type == EventTypes.Redaction and event.redacts is not None:
                 # Insert into the redactions table.
                 self._store_redaction(txn, event)
             elif event.type == EventTypes.Retention:

synapse/storage/data_stores/main/events_worker.py

@@ -287,7 +287,7 @@ def get_events_as_list(
             # we have to recheck auth now.
 
             if not allow_rejected and entry.event.type == EventTypes.Redaction:
-                if not hasattr(entry.event, "redacts"):
+                if entry.event.redacts is None:
                     # A redacted redaction doesn't have a `redacts` key, in
                     # which case lets just withhold the event.
                     #

tests/storage/test_redaction.py

@@ -398,3 +398,38 @@ def test_redact_redaction(self):
         self.get_success(
             self.store.get_event(first_redact_event.event_id, allow_none=True)
         )
+
+    def test_store_redacted_redaction(self):
+        """Tests that we can store a redacted redaction.
+        """
+
+        self.get_success(
+            self.inject_room_member(self.room1, self.u_alice, Membership.JOIN)
+        )
+
+        builder = self.event_builder_factory.for_room_version(
+            RoomVersions.V1,
+            {
+                "type": EventTypes.Redaction,
+                "sender": self.u_alice.to_string(),
+                "room_id": self.room1.to_string(),
+                "content": {"reason": "foo"},
+            },
+        )
+
+        redaction_event, context = self.get_success(
+            self.event_creation_handler.create_new_client_event(builder)
+        )
+
+        self.get_success(
+            self.storage.persistence.persist_event(redaction_event, context)
+        )
+
+        # Now lets jump to the future where we have censored the redaction event
+        # in the DB.
+        self.reactor.advance(60 * 60 * 24 * 31)
+
+        # We just want to check that fetching the event doesn't raise an exception.
+        self.get_success(
+            self.store.get_event(redaction_event.event_id, allow_none=True)
+        )