Use stream ids to filter messages in client-side narrows.

We now use stream ids to filter messages in narrowing
situations, instead of doing stream name comparisons.

This partially fixes certain stream-renaming scenarios, since
we will be able to match the stream id for an out-of-date
stream operand, but it doesn't fix some other stuff, such
as the query that the server gets.

frontend_tests/node_tests/filter.js

@@ -212,6 +212,14 @@ function get_predicate(operators) {
     return new Filter(operators).predicate();
 }
 
+function make_sub(name, stream_id) {
+    var sub = {
+        name: name,
+        stream_id: stream_id,
+    };
+    global.stream_data.add_sub(name, sub);
+}
+
 (function test_predicate_basics() {
     // Predicates are functions that accept a message object with the message
     // attributes (not content), and return true if the message belongs in a
@@ -220,12 +228,22 @@ function get_predicate(operators) {
     //
     // To keep these tests simple, we only pass objects with a few relevant attributes
     // rather than full-fledged message objects.
+
+    var stream_id = 42;
+    make_sub('Foo', stream_id);
     var predicate = get_predicate([['stream', 'Foo'], ['topic', 'Bar']]);
-    assert(predicate({type: 'stream', stream: 'foo', subject: 'bar'}));
-    assert(!predicate({type: 'stream', stream: 'foo', subject: 'whatever'}));
-    assert(!predicate({type: 'stream', stream: 'wrong'}));
+
+    assert(predicate({type: 'stream', stream_id: stream_id, subject: 'bar'}));
+    assert(!predicate({type: 'stream', stream_id: stream_id, subject: 'whatever'}));
+    assert(!predicate({type: 'stream', stream_id: 9999999}));
     assert(!predicate({type: 'private'}));
 
+    // For old streams that we are no longer subscribed to, we may not have
+    // a sub, but these should still match by stream name.
+    predicate = get_predicate([['stream', 'old-Stream'], ['topic', 'Bar']]);
+    assert(predicate({type: 'stream', stream: 'Old-stream', subject: 'bar'}));
+    assert(!predicate({type: 'stream', stream: 'no-match', subject: 'whatever'}));
+
     predicate = get_predicate([['search', 'emoji']]);
     assert(predicate({}));
 
@@ -299,12 +317,15 @@ function get_predicate(operators) {
     var predicate;
     var narrow;
 
+    var social_stream_id = 555;
+    make_sub('social', social_stream_id);
+
     narrow = [
         {operator: 'stream', operand: 'social', negated: true},
     ];
     predicate = new Filter(narrow).predicate();
-    assert(predicate({type: 'stream', stream: 'devel'}));
-    assert(!predicate({type: 'stream', stream: 'social'}));
+    assert(predicate({type: 'stream', stream_id: 999999}));
+    assert(!predicate({type: 'stream', stream_id: social_stream_id}));
 }());
 
 (function test_mit_exceptions() {

static/js/filter.js

@@ -82,6 +82,17 @@ function message_matches_search_term(message, operator, operand) {
         if (page_params.realm_is_zephyr_mirror_realm) {
             return zephyr_stream_name_match(message, operand);
         }
+
+        // Try to match by stream_id if have a valid sub for
+        // the operand.
+        var stream_id = stream_data.get_stream_id(operand);
+        if (stream_id) {
+            return (message.stream_id === stream_id);
+        }
+
+        // We need this fallback logic in case we have a message
+        // loaded for a stream that we are no longer
+        // subscribed to (or that was deleted).
         return (message.stream.toLowerCase() === operand);
 
     case 'topic':