model: Add TODOs to remove aging fallbacks, once less risky

Author: chrisbobbe

src/alertWords/__tests__/alertWordsReducer-test.js

@@ -20,6 +20,7 @@ describe('alertWordsReducer', () => {
       expect(actualState).toEqual(expectedState);
     });
 
+    // TODO(#5102): Delete; see comment on implementation.
     test('when no `alert_words` data is given reset state', () => {
       const initialState = deepFreeze(['word']);
       const action = deepFreeze({

src/alertWords/alertWordsReducer.js

@@ -15,7 +15,15 @@ export default (
       return initialState;
 
     case REGISTER_COMPLETE:
-      return action.data.alert_words || initialState;
+      return (
+        action.data.alert_words
+        // TODO(#5102): Delete fallback once we enforce any threshold for
+        //   ancient servers we refuse to connect to. It was added in #2878
+        //   (2018-11-16), but it wasn't clear even then, it seems, whether
+        //   any servers actually omit the data. The API doc doesn't mention
+        //   any servers that omit it, and our Flow types mark it required.
+        || initialState
+      );
 
     case EVENT_ALERT_WORDS:
       return action.alert_words || initialState;

src/mute/__tests__/muteModel-test.js

@@ -30,6 +30,7 @@ describe('reducer', () => {
       expect(newState && getMute(newState)).toEqual(makeMuteState([[eg.stream, 'topic']]));
     });
 
+    // TODO(#5102): Delete; see comment on implementation.
     test('when no `mute` data is given reset state', () => {
       const state = makeMuteState([[eg.stream, 'topic']]);
       const action = eg.mkActionRegisterComplete({ muted_topics: [] });

src/mute/muteModel.js

@@ -55,7 +55,17 @@ export const reducer = (
       // We require this `globalState` to reflect the `streams` sub-reducer
       // already having run, so that `getStreamsByName` gives the data we
       // just received.  See this sub-reducer's call site in `reducers.js`.
-      return convert(action.data.muted_topics ?? [], getStreamsByName(globalState));
+      return convert(
+        action.data.muted_topics
+          // TODO(#5102): Delete fallback once we enforce any threshold for
+          //   ancient servers we refuse to connect to. It was added in
+          //   #2878 (2018-11-16), but it wasn't clear even then, it seems,
+          //   whether any servers actually omit the data. The API doc
+          //   doesn't mention any servers that omit it, and our Flow types
+          //   mark it required.
+          ?? [],
+        getStreamsByName(globalState),
+      );
 
     case EVENT_MUTED_TOPICS:
       return convert(action.muted_topics, getStreamsByName(globalState));

src/presence/__tests__/presenceReducer-test.js

@@ -47,6 +47,7 @@ describe('presenceReducer', () => {
       expect(actualState).toEqual(presenceData);
     });
 
+    // TODO(#5102): Delete; see comment on implementation.
     test('when no `presence` data is given reset state', () => {
       const initialState = deepFreeze({
         '[email protected]': {

src/presence/presenceReducer.js

@@ -25,7 +25,16 @@ export default (
       return initialState;
 
     case REGISTER_COMPLETE:
-      return action.data.presences || initialState;
+      return (
+        action.data.presences
+        // TODO(#5102): Delete fallback once we enforce any threshold for
+        //   ancient servers we refuse to connect to. It was added in
+        //   #2878 (2018-11-16), but it wasn't clear even then, it seems,
+        //   whether any servers actually omit the data. The API doc
+        //   doesn't mention any servers that omit it, and our Flow types
+        //   mark it required.
+        || initialState
+      );
 
     case PRESENCE_RESPONSE:
       return {

src/unread/unreadHuddlesReducer.js

@@ -96,7 +96,13 @@ export default (
       return initialState;
 
     case REGISTER_COMPLETE:
-      return (action.data.unread_msgs && action.data.unread_msgs.huddles) || initialState;
+      return (
+        (action.data.unread_msgs && action.data.unread_msgs.huddles)
+        // TODO(#5102): Delete fallback once we refuse to connect to Zulip
+        //   servers before 1.7.0, when it seems this feature was added; see
+        //   comment on InitialDataUpdateMessageFlags.
+        || initialState
+      );
 
     case EVENT_NEW_MESSAGE:
       return eventNewMessage(state, action);

src/unread/unreadMentionsReducer.js

@@ -54,7 +54,13 @@ export default (
       return initialState;
 
     case REGISTER_COMPLETE:
-      return (action.data.unread_msgs && action.data.unread_msgs.mentions) || initialState;
+      return (
+        (action.data.unread_msgs && action.data.unread_msgs.mentions)
+        // TODO(#5102): Delete fallback once we refuse to connect to Zulip
+        //   servers before 1.7.0, when it seems this feature was added; see
+        //   comment on InitialDataUpdateMessageFlags.
+        || initialState
+      );
 
     case EVENT_NEW_MESSAGE: {
       const { flags } = action.message;

src/unread/unreadModel.js

@@ -230,8 +230,9 @@ function streamsReducer(
       return initialStreamsState;
 
     case REGISTER_COMPLETE: {
-      // This may indeed be unnecessary, but it's legacy; have not investigated
-      // if it's this bit of our API types that is too optimistic.
+      // TODO(#5102): Delete fallback once we refuse to connect to Zulip
+      //   servers before 1.7.0, when it seems this feature was added; see
+      //   comment on InitialDataUpdateMessageFlags.
       // flowlint-next-line unnecessary-optional-chain:off
       const data = action.data.unread_msgs?.streams ?? [];
 

src/unread/unreadPmsReducer.js

@@ -96,7 +96,13 @@ export default (
       return initialState;
 
     case REGISTER_COMPLETE:
-      return (action.data.unread_msgs && action.data.unread_msgs.pms) || initialState;
+      return (
+        (action.data.unread_msgs && action.data.unread_msgs.pms)
+        // TODO(#5102): Delete fallback once we refuse to connect to Zulip
+        //   servers before 1.7.0, when it seems this feature was added; see
+        //   comment on InitialDataUpdateMessageFlags.
+        || initialState
+      );
 
     case EVENT_NEW_MESSAGE:
       return eventNewMessage(state, action);