combined feed: Tap behavior inconsistent in the channel portion of recipient headers

[chrisbobbe]

When you tap anywhere in the channel part of a recipient header—

it should take you to the channel feed. If your tap is in that area but not on the channel icon "#", the channel name, or the ">", then we actually take you to the page for the specific topic. That's confusing, because you meant to go to the channel.

This will also be relevant for the channel action sheet, which will be offered on long-press in this area:

• UI for channel muting/unmuting #347
• UI for channel subscription settings other than muted/unmuted #1223
• Offer subscribe/unsubscribe in channel action sheet #1224
• Offer "Mark channel as read" in channel action sheet #1226
• Offer "Copy link to channel" in channel action sheet #1227

Implementation

I believe the bug can be fixed by adding a line to the relevant GestureDetector:

diff --git lib/widgets/message_list.dart lib/widgets/message_list.dart
index 48c0d70b5..7d51d6fbd 100644
--- lib/widgets/message_list.dart
+++ lib/widgets/message_list.dart
@@ -1080,6 +1080,7 @@ class StreamMessageRecipientHeader extends StatelessWidget {
         ?? zulipLocalizations.unknownChannelName; // TODO(log)
 
       streamWidget = GestureDetector(
+        behavior: HitTestBehavior.opaque,
         onTap: () => Navigator.push(context,
           MessageListPage.buildRoute(context: context,
             narrow: ChannelNarrow(message.streamId))),

We also need a widget test for the fix; we won't merge a PR without this. The test should pass after the fix and fail before the fix.

[gnprice]

Thanks! Is this the same as #1179?

If so, then let's copy over the added details from this report (including that diagram) and close this one to consolidate.

[E-m-i-n-e-n-c-e]

Hi I have worked on this. The issue was that gesture detector does not detect empty spaces properly if it's hit test behavior is not set to opaque. I have also added a test that taps 3 px above the chevron icon and checks if it navigates correctly to the channel feed. Currently there is 11 px empty space below and above the icon. The test should work correctly unless the padding is drastically reduced. We could also have it tap just 1 px above the icon instead and it should still theoretically work the same

[chrisbobbe]

Thanks! Is this the same as #1179?

If so, then let's copy over the added details from this report (including that diagram) and close this one to consolidate.

Ah, yep! Done. @E-m-i-n-e-n-c-e, I see you've opened a PR pointing to this issue—please adjust it to point to #1179 instead; thanks.