[DPE-5565] Upgrade dataplatform libs to v38

lib/charms/data_platform_libs/v0/data_interfaces.py

@@ -331,7 +331,7 @@ def _on_topic_requested(self, event: TopicRequestedEvent):
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 35
+LIBPATCH = 38
 
 PYDEPS = ["ops>=2.0.0"]
 
@@ -642,22 +642,26 @@ def _move_to_new_label_if_needed(self):
             return
 
         # Create a new secret with the new label
-        old_meta = self._secret_meta
         content = self._secret_meta.get_content()
+        self._secret_uri = None
 
         # I wish we could just check if we are the owners of the secret...
         try:
             self._secret_meta = self.add_secret(content, label=self.label)
         except ModelError as err:
             if "this unit is not the leader" not in str(err):
                 raise
-        old_meta.remove_all_revisions()
+        self.current_label = None
 
     def set_content(self, content: Dict[str, str]) -> None:
         """Setting cached secret content."""
         if not self.meta:
             return
 
+        # DPE-4182: do not create new revision if the content stay the same
+        if content == self.get_content():
+            return
+
         if content:
             self._move_to_new_label_if_needed()
             self.meta.set_content(content)
@@ -1586,7 +1590,7 @@ def _register_secret_to_relation(
         """
         label = self._generate_secret_label(relation_name, relation_id, group)
 
-        # Fetchin the Secret's meta information ensuring that it's locally getting registered with
+        # Fetching the Secret's meta information ensuring that it's locally getting registered with
         CachedSecret(self._model, self.component, label, secret_id).meta
 
     def _register_secrets_to_relation(self, relation: Relation, params_name_list: List[str]):
@@ -2309,7 +2313,7 @@ def _secrets(self) -> dict:
         return self._cached_secrets
 
     def _get_secret(self, group) -> Optional[Dict[str, str]]:
-        """Retrieveing secrets."""
+        """Retrieving secrets."""
         if not self.app:
             return
         if not self._secrets.get(group):
@@ -2602,6 +2606,14 @@ def set_version(self, relation_id: int, version: str) -> None:
         """
         self.update_relation_data(relation_id, {"version": version})
 
+    def set_subordinated(self, relation_id: int) -> None:
+        """Raises the subordinated flag in the application relation databag.
+
+        Args:
+            relation_id: the identifier for a particular relation.
+        """
+        self.update_relation_data(relation_id, {"subordinated": "true"})
+
 
 class DatabaseProviderEventHandlers(EventHandlers):
     """Provider-side of the database relation handlers."""
@@ -2838,6 +2850,21 @@ def _on_relation_created_event(self, event: RelationCreatedEvent) -> None:
 
     def _on_relation_changed_event(self, event: RelationChangedEvent) -> None:
         """Event emitted when the database relation has changed."""
+        is_subordinate = False
+        remote_unit_data = None
+        for key in event.relation.data.keys():
+            if isinstance(key, Unit) and not key.name.startswith(self.charm.app.name):
+                remote_unit_data = event.relation.data[key]
+            elif isinstance(key, Application) and key.name != self.charm.app.name:
+                is_subordinate = event.relation.data[key].get("subordinated") == "true"
+
+        if is_subordinate:
+            if not remote_unit_data:
+                return
+
+            if remote_unit_data.get("state") != "ready":
+                return
+
         # Check which data has changed to emit customs events.
         diff = self._diff(event)