fix: Fix conditional use_effect in use_table_listener

plugins/ui/src/deephaven/ui/hooks/use_table_data.py

@@ -142,6 +142,10 @@ def use_table_data(
 
     table_updated = lambda: _set_new_data(table, sentinel, set_data, set_is_sentinel)
 
+    # call table_updated in the case of new table or sentinel
+    ui.use_effect(table_updated, [table, sentinel])
+
+    # call table_updated every time the table updates
     ui.use_table_listener(
         table, partial(_on_update, ctx, table_updated, executor_name), []
     )

plugins/ui/src/deephaven/ui/hooks/use_table_listener.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from functools import partial
-from typing import Any, Callable, Sequence
+from typing import Callable
 
 from deephaven.table import Table
 from deephaven.table_listener import listen, TableUpdate, TableListener
@@ -86,17 +86,16 @@ def use_table_listener(
         replay_lock: The lock type used during replay, default is ‘shared’, can also be ‘exclusive’.
     """
 
-    if not table.is_refreshing and not do_replay:
-        # if the table is not refreshing, and is not replaying, there is nothing to listen to
-        return
-
     def start_listener() -> Callable[[], None]:
         """
         Start the listener. Returns a function that can be called to stop the listener by the use_effect hook.
 
         Returns:
             A function that can be called to stop the listener by the use_effect hook.
         """
+        if not table.is_refreshing and not do_replay:
+            return lambda: None
+
         handle = listen(
             table,
             wrap_listener(listener),

plugins/ui/test/deephaven/ui/test_hooks.py

@@ -274,6 +274,51 @@ def _test_table_data(t=table):
 
         self.assertEqual(result, expected)
 
+    def test_swapping_table_data(self):
+        from deephaven.ui.hooks import use_table_data
+        from deephaven import new_table
+        from deephaven.column import int_col
+        from deephaven import DynamicTableWriter
+        import deephaven.dtypes as dht
+
+        table = new_table(
+            [
+                int_col("X", [1, 2, 3]),
+                int_col("Y", [2, 4, 6]),
+            ]
+        )
+
+        def _test_table_data(t=table):
+            result = use_table_data(t, sentinel="sentinel")
+            return result
+
+        render_result = render_hook(_test_table_data)
+
+        result, rerender = itemgetter("result", "rerender")(render_result)
+
+        column_definitions = {"Numbers": dht.int32, "Words": dht.string}
+
+        table_writer = DynamicTableWriter(column_definitions)
+        dynamic_table = table_writer.table
+
+        # Need two rerenders because the first one will call set_data, which queues state updates
+        # that are resolved at the start of the second rerender
+        # The second rerender will then have the expected state values and return the expected result
+        rerender(dynamic_table)
+        result = rerender(dynamic_table)
+
+        # the initial render should return the sentinel value since the table is empty
+        self.assertEqual(result, "sentinel")
+
+        self.verify_table_updated(table_writer, dynamic_table, (1, "Testing"))
+
+        rerender(dynamic_table)
+        result = rerender(dynamic_table)
+
+        expected = {"Numbers": [1], "Words": ["Testing"]}
+
+        self.assertEqual(result, expected)
+
     def test_column_data(self):
         from deephaven.ui.hooks import use_column_data
         from deephaven import new_table