recent_topics: Don't render topic of deactivatedstreams.

Fixes error when trying to render topic of a deactivated stream in
the Recent Topics widget.

frontend_tests/node_tests/recent_topics.js

@@ -7,18 +7,6 @@ set_global('$', global.make_zjquery({
 set_global('hashchange', {
     exit_overlay: noop,
 });
-set_global('stream_data', {
-    get_sub_by_id: () => ({
-        color: "",
-        invite_only: false,
-        is_web_public: true,
-    }),
-    is_muted: () =>
-        // We only test via muted topics for now.
-        // TODO: Make muted streams and test them.
-        false
-    ,
-});
 set_global('overlays', {
     open_overlay: (opts) => {
         overlays.close_callback = opts.on_close;
@@ -89,6 +77,7 @@ const stream1 = 1;
 const stream2 = 2;
 const stream3 = 3;
 const stream4 = 4;
+const stream5 = 5; // Deleted stream
 
 // Topics in the stream, all unread except topic1 & stream1.
 const topic1 = "topic-1";  // No Other sender & read.
@@ -128,6 +117,25 @@ set_global('message_list', {
 set_global('message_store', {
     get: (msg_id) => messages[msg_id - 1],
 });
+set_global('stream_data', {
+    get_sub_by_id: (stream) => {
+        if (stream === stream5) {
+            // No data is available for deactivated streams
+            return;
+        }
+
+        return {
+            color: "",
+            invite_only: false,
+            is_web_public: true,
+        };
+    },
+    is_muted: () =>
+        // We only test via muted topics for now.
+        // TODO: Make muted streams and test them.
+        false
+    ,
+});
 
 let id = 0;
 
@@ -681,6 +689,13 @@ run_test('test_topic_edit', () => {
 
     assert.equal(all_topics.get(get_topic_key(stream2, topic1)), undefined);
     verify_topic_data(all_topics, stream3, topic9, messages[0].id, true);
+
+    // Message was moveed to a deleted stream, hence hidden regardless of filter.
+    messages[0].stream_id = stream5;
+    messages[0].topic = topic8;
+    rt.process_topic_edit(stream3, topic9, topic8, stream5);
+    all_topics = rt.get();
+    assert.equal(rt.filters_should_hide_topic(all_topics.get('5:topic-8')), true);
 });
 
 run_test('test_search', () => {

static/js/recent_topics.js

@@ -154,6 +154,10 @@ function format_topic(topic_data) {
     const stream = last_msg.stream;
     const stream_id = last_msg.stream_id;
     const stream_info = stream_data.get_sub_by_id(stream_id);
+    if (stream_info === undefined) {
+        // stream was deleted
+        return {};
+    }
     const topic = last_msg.topic;
     const time = new XDate(last_msg.timestamp * 1000);
     const last_msg_time = timerender.last_seen_status_from_date(time);
@@ -232,9 +236,14 @@ exports.topic_in_search_results = function (keyword, stream, topic) {
     });
 };
 
-function filters_should_hide_topic(topic_data) {
+exports.filters_should_hide_topic = function (topic_data) {
     const msg = message_store.get(topic_data.last_msg_id);
 
+    if (stream_data.get_sub_by_id(msg.stream_id) === undefined) {
+        // Never try to process deactivated streams.
+        return true;
+    }
+
     if (filters.has('unread')) {
         const unreadCount = unread.unread_topic_counter.get(msg.stream_id, msg.topic);
         if (unreadCount === 0) {
@@ -260,7 +269,7 @@ function filters_should_hide_topic(topic_data) {
     }
 
     return false;
-}
+};
 
 exports.inplace_rerender = function (topic_key) {
     if (!overlays.recent_topics_open()) {
@@ -274,7 +283,7 @@ exports.inplace_rerender = function (topic_key) {
     topics_widget.render_item(topic_data);
     const topic_row = get_topic_row(topic_data);
 
-    if (filters_should_hide_topic(topic_data)) {
+    if (exports.filters_should_hide_topic(topic_data)) {
         topic_row.hide();
     } else {
         topic_row.show();
@@ -402,7 +411,7 @@ exports.complete_rerender = function () {
             // We use update_filters_view & filters_should_hide_topic to do all the
             // filtering for us, which is called using click_handlers.
             predicate: function (topic_data) {
-                return !filters_should_hide_topic(topic_data);
+                return !exports.filters_should_hide_topic(topic_data);
             },
         },
         sort_fields: {