bugfix: core: Fix message not focused in all_msg narrow if anchored.

This bugfix allows messages to be focused when narrowing to the
"all_messages" narrow from other narrows.

The primary bug was if the message from which we press 'a' was not
present in model.index['all_msg_ids'], then we were not fetching
that from the server. The reason we were not fetching those messages
was we only checked if the final narrow is not empty, which in this
case will never be, and not if it contains the message we are
focusing to. This made the focus to move elsewhere in the
"all_messages" narrow.

This also fixes part of #934 as a side-effect.

Tests added.

Author: zee-bit

tests/core/test_core.py

@@ -205,7 +205,11 @@ def test_narrow_to_user(self, mocker, controller, user_button, index_user):
         id_list = index_user["private_msg_ids_by_user_ids"][recipients]
         assert {widget.original_widget.message["id"]} == id_list
 
-    def test_narrow_to_all_messages(self, mocker, controller, index_all_messages):
+    @pytest.mark.parametrize("anchor", [None, 537286])
+    def test_narrow_to_all_messages(
+        self, mocker, controller, index_all_messages, anchor
+    ):
+        expected_final_focus_msg_id = 537288 if anchor is None else anchor
         controller.model.narrow = [["stream", "PTEST"]]
         controller.model.index = index_all_messages
         controller.view.message_view = mocker.patch("urwid.ListBox")
@@ -219,15 +223,17 @@ def test_narrow_to_all_messages(self, mocker, controller, index_all_messages):
         controller.model.muted_streams = []
         controller.model.is_muted_topic = mocker.Mock(return_value=False)
 
-        controller.narrow_to_all_messages()  # FIXME: Add id narrowing test
+        controller.narrow_to_all_messages(contextual_message_id=anchor)
 
         assert controller.model.narrow == []
         controller.view.message_view.log.clear.assert_called_once_with()
 
-        widgets = controller.view.message_view.log.extend.call_args_list[0][0][0]
+        widgets, focus = controller.view.message_view.log.extend.call_args_list[0][0]
         id_list = index_all_messages["all_msg_ids"]
         msg_ids = {widget.original_widget.message["id"] for widget in widgets}
+        final_focus_msg_id = widgets[focus].original_widget.message["id"]
         assert msg_ids == id_list
+        assert final_focus_msg_id == expected_final_focus_msg_id
 
     def test_narrow_to_all_pm(self, mocker, controller, index_user):
         controller.model.narrow = []

zulipterminal/core.py

@@ -392,8 +392,11 @@ def _narrow_to(self, anchor: Optional[int], **narrow: Any) -> None:
 
         msg_id_list = self.model.get_message_ids_in_current_narrow()
 
-        # if no messages are found get more messages
-        if len(msg_id_list) == 0:
+        # If no messages are found in the current narrow
+        # OR, given anchor is not present in msg_id_list
+        # then, get more messages.
+        # Refer commit 07faeb04ccca7d32f7580e39536cdbb5a190a460 for related bugfix
+        if len(msg_id_list) == 0 or (anchor is not None and anchor not in msg_id_list):
             self.model.get_messages(num_before=30, num_after=10, anchor=anchor)
             msg_id_list = self.model.get_message_ids_in_current_narrow()