explicit_default_catalog

Signed-off-by: Andreas Fredhøi <andreas.fredhoi@fresio.no>

Author: fresioAS

sqlmesh/core/engine_adapter/fabric.py

@@ -170,9 +170,15 @@ def set_current_catalog(self, catalog_name: t.Optional[str]) -> None:
             https://learn.microsoft.com/en-us/fabric/data-warehouse/sql-query-editor#limitations
         """
         target_catalog = self._normalize_catalog(catalog_name)
+        explicit_default_catalog = catalog_name is not None and target_catalog is None
+        connected_catalog = self._normalize_catalog(self._connected_catalog)
 
-        # No-op: the logical catalog state already matches.
-        if self.get_current_catalog() == target_catalog:
+        # An explicit request for the default catalog must also match the catalog
+        # used by the open connection. A lazy restore with None only updates the
+        # logical target and intentionally leaves that connection in place.
+        if self.get_current_catalog() == target_catalog and (
+            not explicit_default_catalog or connected_catalog is None
+        ):
             logger.debug("Already using requested Fabric catalog state, no action needed")
             return
 
@@ -192,8 +198,9 @@ def set_current_catalog(self, catalog_name: t.Optional[str]) -> None:
         #    open connection is already on a different catalog.  If a previous
         #    restore-to-neutral left the connection on the right catalog, we
         #    skip the close entirely.
-        connected_catalog = self._normalize_catalog(self._connected_catalog)
-        needs_reconnect = target_catalog is not None and connected_catalog != target_catalog
+        needs_reconnect = (target_catalog is not None or explicit_default_catalog) and (
+            connected_catalog != target_catalog
+        )
 
         if needs_reconnect:
             logger.info(

tests/core/engine_adapter/test_fabric.py

@@ -101,6 +101,26 @@ def test_catalog_scoped_call_restores_to_neutral_without_close(
     assert adapter.get_current_catalog() is None
 
 
+def test_default_catalog_after_non_default_catalog_reconnects(
+    make_mocked_engine_adapter: t.Callable,
+    mocker: MockerFixture,
+):
+    adapter = make_mocked_engine_adapter(
+        FabricEngineAdapter,
+        default_catalog="core",
+        database="core",
+    )
+    close_spy = mocker.spy(adapter._connection_pool, "close")
+    adapter.cursor.fetchone.return_value = (1,)
+
+    adapter.table_exists("planning.db.table")
+    adapter.table_exists("core.db.table")
+
+    assert close_spy.call_count == 2
+    assert adapter._connected_catalog is None
+    assert adapter.get_current_catalog() is None
+
+
 def test_repeated_same_catalog_reuses_connection(
     make_mocked_engine_adapter: t.Callable,
     mocker: MockerFixture,