internal_link: Parse topic permalinks

This `with` operator (as in `/with/NNNN`) is just accepted and
ignored as of this change.  Interpreting them is zulip#683.

Fixes: zulip#684

Author: sm-sayedi

lib/model/internal_link.dart

@@ -179,8 +179,9 @@ Narrow? _interpretNarrowSegments(List<String> segments, PerAccountStore store) {
         if (dmIds == null) return null;
         dmElement = ApiNarrowDm(dmIds, negated: negated);
 
-      case _NarrowOperator.near:
-        continue; // TODO(#82): support for near
+      case _NarrowOperator.near: // TODO(#82): support for near
+      case _NarrowOperator.with_: // TODO(#683): support for with
+        continue;
 
       case _NarrowOperator.unknown:
         return null;
@@ -206,6 +207,9 @@ enum _NarrowOperator {
   // 'dm' is new in server-7.0; means the same as 'pm-with'
   dm,
   near,
+  // cannot use `with` as it is a reserved keyword in Dart
+  @JsonValue('with')
+  with_,
   pmWith,
   stream,
   channel,

lib/model/internal_link.g.dart

@@ -172,9 +172,12 @@ void main() {
       const testCases = [
         ('/#narrow/stream/check/topic/test',                 TopicNarrow(1, 'test')),
         ('/#narrow/stream/mobile/subject/topic/near/378333', TopicNarrow(3, 'topic')),
+        ('/#narrow/stream/mobile/subject/topic/with/1',      TopicNarrow(3, 'topic')),
         ('/#narrow/stream/mobile/topic/topic/',              TopicNarrow(3, 'topic')),
         ('/#narrow/stream/stream/topic/topic/near/1',        TopicNarrow(5, 'topic')),
+        ('/#narrow/stream/stream/topic/topic/with/22',       TopicNarrow(5, 'topic')),
         ('/#narrow/stream/stream/subject/topic/near/1',      TopicNarrow(5, 'topic')),
+        ('/#narrow/stream/stream/subject/topic/with/333',    TopicNarrow(5, 'topic')),
         ('/#narrow/stream/stream/subject/topic',             TopicNarrow(5, 'topic')),
       ];
       testExpectedNarrows(testCases, streams: streams);
@@ -198,7 +201,9 @@ void main() {
       final testCases = [
         ('/#narrow/dm/1,2-group',                        expectedNarrow),
         ('/#narrow/dm/1,2-group/near/1',                 expectedNarrow),
+        ('/#narrow/dm/1,2-group/with/2',                 expectedNarrow),
         ('/#narrow/dm/a.40b.2Ecom.2Ec.2Ed.2Ecom/near/3', null),
+        ('/#narrow/dm/a.40b.2Ecom.2Ec.2Ed.2Ecom/with/4', null),
       ];
       testExpectedNarrows(testCases, streams: streams);
     });
@@ -209,7 +214,9 @@ void main() {
       final testCases = [
         ('/#narrow/pm-with/1,2-group',                        expectedNarrow),
         ('/#narrow/pm-with/1,2-group/near/1',                 expectedNarrow),
+        ('/#narrow/pm-with/1,2-group/with/2',                 expectedNarrow),
         ('/#narrow/pm-with/a.40b.2Ecom.2Ec.2Ed.2Ecom/near/3', null),
+        ('/#narrow/pm-with/a.40b.2Ecom.2Ec.2Ed.2Ecom/with/3', null),
       ];
       testExpectedNarrows(testCases, streams: streams);
     });