Fix /sync example (#2077)

* Fix sync example

The same event should not appear in `state` and in the `timeline` so we cannot use the same event twice.

To provide a `state` example we assume that with lazy-loading the user did not get the state event for `@example:example.org`, so we add one since they sent a message in the timeline.

The events that are referenced include a `room_id`, which doesn't appear on this endpoint, so we copy them without it.

Finally, the `join` event of `@alice:example.org` is wrong because the sender does not match the state key, which wouldn't pass the authorization rules.

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

* Fix the `m.room.member.yaml` example

This is a `join` event, and the `sender` doesn't match the `state_key`, so the event couldn't pass the authorization rules.

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

* Add changelog

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

---------

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

changelogs/client_server/newsfragments/2077.clarification

@@ -0,0 +1 @@
+Fix the example of the `GET /sync` endpoint and the `m.room.member` example used in several places.

data/api/client-server/sync.yaml

@@ -441,17 +441,57 @@ paths:
                           "state": {
                             "events": [
                               {
-                                "$ref": "../../event-schemas/examples/m.room.member.yaml"
+                                "content": {
+                                  "avatar_url": "mxc://example.org/SFHyPlCeYUSFFxlgbQYZmoEoe",
+                                  "displayname": "Example user",
+                                  "membership": "join"
+                                },
+                                "event_id": "$143273976499sgjks:example.org",
+                                "origin_server_ts": 1432735824653,
+                                "sender": "@example:example.org",
+                                "state_key": "@example:example.org",
+                                "type": "m.room.member",
+                                "unsigned": {
+                                  "age": 45603,
+                                  "membership": "join"
+                                }
                               }
                             ]
                           },
                           "timeline": {
                             "events": [
                               {
-                                "$ref": "../../event-schemas/examples/m.room.member.yaml"
+                                "content": {
+                                  "avatar_url": "mxc://example.org/SEsfnsuifSDFSSEF",
+                                  "displayname": "Alice Margatroid",
+                                  "membership": "join",
+                                  "reason": "Looking for support"
+                                },
+                                "event_id": "$143273582443PhrSn:example.org",
+                                "origin_server_ts": 1432735824653,
+                                "sender": "@alice:example.org",
+                                "state_key": "@alice:example.org",
+                                "type": "m.room.member",
+                                "unsigned": {
+                                  "age": 1234,
+                                  "membership": "join"
+                                }
                               },
                               {
-                                "$ref": "../../event-schemas/examples/m.room.message$m.text.yaml"
+                                "content": {
+                                  "body": "This is an example text message",
+                                  "format": "org.matrix.custom.html",
+                                  "formatted_body": "<b>This is an example text message</b>",
+                                  "msgtype": "m.text"
+                                },
+                                "event_id": "$143273582443PhrSn:example.org",
+                                "origin_server_ts": 1432735824653,
+                                "sender": "@example:example.org",
+                                "type": "m.room.message",
+                                "unsigned": {
+                                  "age": 1234,
+                                  "membership": "join"
+                                }
                               }
                             ],
                             "limited": true,

data/event-schemas/examples/m.room.member.yaml

@@ -1,6 +1,7 @@
 {
   "$ref": "core/state_event.json",
   "state_key": "@alice:example.org",
+  "sender": "@alice:example.org",
   "type": "m.room.member",
   "content": {
     "membership": "join",