Add a invite_state key for holding the state that is bundled with an

invite. This is kept separate from the actual state for the room as
it may be derived from an incomplete, unverified copy of the state
that was bundled with an invite event received over federation.

api/client-server/v2_alpha/sync.yaml

@@ -88,6 +88,9 @@ paths:
                       type: array
                       description: |-
                         A list of room ids that the user has been invited to.
+                        The entries in the room_map will have an
+                        ``invite_state`` key. But will lack the ``ephemeral``
+                        key, the ``timeline`` key and the ``state`` key.
                       items:
                         type: string.
                     archived:
@@ -132,6 +135,21 @@ paths:
                         in the timeline or state of the room. E.g. typing.
                       allOf:
                         - $ref: "definitions/event_batch.json"
+                    invite_state:
+                      description: |-
+                        The state of a room that the user has been invited to.
+                        These state events may only have the ``type``,
+                        ``state_key`` and ``content`` keys present.
+                        These events do not replace any state that the client
+                        already has for the room, for example if the client has
+                        archived the room. Instead the client should keep two
+                        separate copies of the state: the one from the
+                        ``invite_state`` and one from the archived ``state``.
+                        If the client joins the room then the current state
+                        will be given as a delta against the archived ``state``
+                        not the ``invite_state``.
+                      allOf:
+                        - $ref: "definitions/event_batch.json"
               presence:
                 description: |-
                   The updates to the presence status of other users.
@@ -152,7 +170,7 @@ paths:
                 },
                 "rooms": {
                   "default": {
-                    "invited": [],
+                    "invited": ["!696r7674:example.com"],
                     "archived": [],
                     "joined": ["!726s6s6q:example.com"]
                   }
@@ -205,6 +223,24 @@ paths:
                         }
                       ]
                     }
+                  },
+                  "!696r7674:example.com": {
+                    "invite_state": {
+                      "events": [
+                        {
+                          "sender": "@alice:example.com",
+                          "type": "m.room.name",
+                          "state_key": "@alice:example.com",
+                          "content": {"name": "My Room Name"}
+                        },
+                        {
+                          "sender": "@alice:example.com",
+                          "type": "m.room.name",
+                          "state_key": "",
+                          "content": {"membership": "invite"}
+                        }
+                      ]
+                    }
                   }
                 }
               }