Fix #1038. Ensure setting session triggers property changed messages …

…for session, session_metadata.

nion/swift/model/DataItem.py

@@ -759,6 +759,8 @@ def __property_changed(self, name: str, value: typing.Any) -> None:
         if name == "dynamic_title_enabled":
             self.__dynamic_title_enabled_stream.value = value
         self.notify_property_changed(name)
+        if name == "session":
+            self.notify_property_changed("session_metadata")
         if name in ("title", "caption", "description"):
             self.__notify_description_changed()
 

nion/swift/model/DynamicString.py

@@ -74,13 +74,12 @@ class ItemPropertySlug(DynamicStringSlug, typing.Generic[ItemPropertySlugType]):
     """A dynamic string slug that observes a property on an item and converts it to a string."""
     def __init__(self,
                  property: str,
-                 convert_fn: typing.Optional[typing.Callable[[typing.Optional[ItemPropertySlugType]], typing.Optional[str]]],
+                 convert_fn: typing.Optional[typing.Callable[[Observable.Observable, typing.Optional[ItemPropertySlugType]], typing.Optional[str]]],
                  slug: str,
                  default_value: typing.Optional[str] = None) -> None:
         super().__init__(slug, default_value)
         self.__property = property
         self.__convert_fn = convert_fn
-        self.__property_changed_event_listener: typing.Optional[Event.EventListener] = None
         self.__item_value_stream = Stream.PropertyChangedEventStream[ItemPropertySlugType](self._item_stream, self.__property)
         self.__item_value_stream_listener = self.__item_value_stream.value_stream.listen(weak_partial(ItemPropertySlug.__item_property_stream_value_changed, self))
         self.__item_property_stream_value_changed(self.__item_value_stream.value)
@@ -93,7 +92,11 @@ def convert_to_str(value: typing.Optional[ItemPropertySlugType]) -> typing.Optio
             return str(value) if value is not None else None
 
         if self.__convert_fn:
-            self.value = self.__convert_fn(value)
+            item = self._item_stream.value
+            if item:
+                self.value = self.__convert_fn(item, value)
+            else:
+                self.value = None
         else:
             self.value = convert_to_str(value)
 
@@ -208,7 +211,7 @@ def make_dynamic_string(self, dynamic_string_type: str, d: Persistence.Persisten
             return dynamic_string
         if dynamic_string_type == "_slug_test":
 
-            def convert_metadata_to_slug_test_str(value: typing.Optional[Persistence.PersistentDictType]) -> typing.Optional[str]:
+            def convert_metadata_to_slug_test_str(item: Observable.Observable, value: typing.Optional[Persistence.PersistentDictType]) -> typing.Optional[str]:
                 if value is not None:
                     metadata = value
                     return typing.cast(typing.Optional[str], metadata.get("_slug_test", None))

nion/swift/test/DataItem_test.py

@@ -1256,6 +1256,34 @@ def test_data_item_copy_copies_session_info(self):
             self.assertEqual(data_item_copy.session_metadata, data_item.session_metadata)
             self.assertEqual(data_item_copy.session_id, document_model.session_id)
 
+    def test_data_item_setting_session_data_trigger_property_changed_event(self):
+        with TestContext.create_memory_context() as test_context:
+            document_model = test_context.create_document_model()
+            data_item = DataItem.DataItem(numpy.ones((2, 2)))
+            document_model.append_data_item(data_item)
+
+            received_session_changed = False
+            received_session_metadata_changed = False
+
+            def property_changed(name: str) -> None:
+                nonlocal received_session_changed, received_session_metadata_changed
+                if name == 'session':
+                    received_session_changed = True
+                elif name == 'session_metadata':
+                    received_session_metadata_changed = True
+
+            listener = data_item.property_changed_event.listen(property_changed)
+
+            session_metadata = data_item.session_metadata
+            session_metadata['site'] = 'Home'
+            data_item.session_metadata = session_metadata
+
+            listener = None
+
+            self.assertTrue(received_session_changed)
+            self.assertTrue(received_session_metadata_changed)
+
+
     def test_data_item_session_id_independent_from_data_source_session_id(self):
         with TestContext.create_memory_context() as test_context:
             document_model = test_context.create_document_model()