Read a joining local user's profile in one query

A join without profile data read the user's display name and then their
avatar URL, two transactions. For a local user with neither in the
content, `get_profileinfo` now reads both at once. A remote user, or
content that has one of the two, takes the same path as before.

If the user has no profile row, the first read used to fail with a 404,
logged, and leave both out. Now both are left out without the log line.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PVLsNh6akt4ifEizY4D1ta

synapse/handlers/room_member.py

@@ -823,14 +823,26 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             profile = self.profile_handler
 
             try:
-                if "displayname" not in content:
-                    displayname = await profile.get_displayname(target)
-                    if displayname is not None:
-                        content["displayname"] = displayname
-                if "avatar_url" not in content:
-                    avatar_url = await profile.get_avatar_url(target)
-                    if avatar_url is not None:
-                        content["avatar_url"] = avatar_url
+                if (
+                    "displayname" not in content
+                    and "avatar_url" not in content
+                    and self.hs.is_mine(target)
+                ):
+                    # Both in one query.
+                    info = await self.store.get_profileinfo(target)
+                    if info.display_name is not None:
+                        content["displayname"] = info.display_name
+                    if info.avatar_url is not None:
+                        content["avatar_url"] = info.avatar_url
+                else:
+                    if "displayname" not in content:
+                        displayname = await profile.get_displayname(target)
+                        if displayname is not None:
+                            content["displayname"] = displayname
+                    if "avatar_url" not in content:
+                        avatar_url = await profile.get_avatar_url(target)
+                        if avatar_url is not None:
+                            content["avatar_url"] = avatar_url
             except Exception as e:
                 logger.info("Failed to get profile information for %r: %s", target, e)
 

tests/rest/client/test_rooms.py

@@ -3446,6 +3446,24 @@ class PerRoomProfilesForbiddenTestCase(unittest.HomeserverTestCase):
 
         self.room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
 
+    def test_join_has_the_global_profile(self) -> None:
+        """A join without profile data gets the user's display name and
+        avatar."""
+        channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/profile/%s/avatar_url" % (self.user_id,),
+            {"avatar_url": "mxc://test/avatar"},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
+
+        room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
+        member = self.helper.get_state(
+            room_id, "m.room.member", self.tok, state_key=self.user_id
+        )
+        self.assertEqual(member["displayname"], self.displayname)
+        self.assertEqual(member["avatar_url"], "mxc://test/avatar")
+
     def test_per_room_profile_forbidden(self) -> None:
         request_data = {"membership": "join", "displayname": "other test user"}
         channel = self.make_request(