message: Make sure submessages is always defined.

web/src/message_edit.ts

@@ -141,7 +141,7 @@ export function is_topic_editable(message: Message, edit_limit_seconds_buffer =
 }
 
 function is_widget_message(message: Message): boolean {
-    if (message.submessages && message.submessages.length > 0) {
+    if (message.submessages.length > 0) {
         return true;
     }
     return false;

web/src/message_helper.ts

@@ -94,6 +94,7 @@ export function process_new_message(raw_message: RawMessage, deliver_locally = f
             clean_reactions,
             display_reply_to: undefined,
         };
+        message.submessages ??= [];
         message_user_ids.add_user_id(message.sender_id);
     } else {
         const pm_with_user_ids = people.pm_with_user_ids(message_with_booleans);
@@ -114,6 +115,7 @@ export function process_new_message(raw_message: RawMessage, deliver_locally = f
             to_user_ids,
             clean_reactions,
         };
+        message.submessages ??= [];
 
         pm_conversations.process_message(message);
 

web/src/submessage.ts

@@ -65,10 +65,6 @@ export function get_message_events(message: Message): SubmessageEvents | undefin
         return undefined;
     }
 
-    if (!message.submessages) {
-        return undefined;
-    }
-
     if (message.submessages.length === 0) {
         return undefined;
     }
@@ -163,8 +159,6 @@ export function update_message(submsg: Submessage): void {
         return;
     }
 
-    message.submessages ??= [];
-
     const existing = message.submessages.find((sm) => sm.id === submsg.id);
 
     if (existing !== undefined) {

web/tests/message_edit.test.cjs

@@ -53,6 +53,7 @@ run_test("is_content_editable", ({override}) => {
     // user, and that were successfully sent (i.e. no failed_request or local_id)
     const message = {
         sent_by_me: true,
+        submessages: [],
     };
 
     override(realm, "realm_allow_message_editing", false);
@@ -75,7 +76,7 @@ run_test("is_content_editable", ({override}) => {
     // Right now, we prevent users from editing widgets.
     message.submessages = ["/poll"];
     assert.equal(is_content_editable(message, 55), false);
-    delete message.submessages;
+    message.submessages = [];
     message.type = "private";
     assert.equal(is_content_editable(message, 45), false);
 

web/tests/message_events.test.cjs

@@ -166,6 +166,7 @@ run_test("update_messages", ({override, override_rewire}) => {
             status_emoji_info: undefined,
             stream_id: denmark.stream_id,
             stream: "Denmark",
+            submessages: [],
             topic: "lunch",
             type: "stream",
             unread: true,

web/tests/popover_menus_data.test.cjs

@@ -203,6 +203,7 @@ test("my_message_all_actions", ({override}) => {
             unread: false,
             collapsed: false,
             not_spectator: true,
+            submessages: [],
             edit_history: [
                 {
                     prev_content: "Previous content",

web/tests/submessage.test.cjs

@@ -13,11 +13,7 @@ const widgetize = mock_esm("../src/widgetize");
 const submessage = zrequire("submessage");
 
 run_test("get_message_events", () => {
-    let msg = {};
-
-    assert.equal(submessage.get_message_events(msg), undefined);
-
-    msg = {
+    let msg = {
         submessages: [],
     };
     assert.equal(submessage.get_message_events(msg), undefined);
@@ -117,6 +113,7 @@ run_test("check sender", ({override}) => {
 run_test("handle_event", () => {
     const message = {
         id: 42,
+        submessages: [],
     };
 
     const event = {