Merge a862fd1786 into 65b1db721d

We seem to have [updated this for m.room.name](https://github.com/matrix-org/matrix-spec/pull/1639) some years back but omitted it for topic.

.github/workflows/main.yml

@@ -283,10 +283,11 @@ jobs:
           npm i
           npm run get-proposals
       - name: "⚙️ hugo"
+        env:
+          HUGO_PARAMS_VERSION_STATUS: "historical"
         # Create a baseURL like `/v1.2` out of the `v1.2` tag
         run: |
-          echo -e '[params.version]\nstatus="historical"' > historical.toml
-          hugo --config config.toml,historical.toml --baseURL "/${GITHUB_REF/refs\/tags\//}" -d "spec"
+          hugo --baseURL "/${GITHUB_REF/refs\/tags\//}" -d "spec"
 
       - name: "📥 Spec definition download"
         uses: actions/download-artifact@v4

changelogs/client_server/newsfragments/2068.clarification

@@ -0,0 +1 @@
+Clarify behaviour when the `topic` key of a `m.room.topic` event is absent, null, or empty.

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.

changelogs/internal/newsfragments/2123.clarification

@@ -0,0 +1 @@
+Fix the historical info box when generating the historical spec in CI.

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",

data/event-schemas/schema/m.room.topic.yaml

@@ -1,7 +1,14 @@
 ---
 allOf:
   - $ref: core-event-schema/state_event.yaml
-description: 'A topic is a short message detailing what is currently being discussed in the room.  It can also be used as a way to display extra information about the room, which may not be suitable for the room name. The room topic can also be set when creating a room using `/createRoom` with the `topic` key.'
+description: |- 
+    A topic is a short message detailing what is currently being discussed in the room.
+    It can also be used as a way to display extra information about the room, which may not
+    be suitable for the room name.
+    The room topic can also be set when creating a room using `/createRoom` with the `topic` key.'
+    
+    If the `topic` property is absent, null, or empty then the topic is unset. In other words,
+    an empty `topic` property effectively resets the room to having no topic.
 properties:
   content:
     properties: