fix(table): closing a table tab releases its lease without interrupting the shared session (#1215)

lib/features/mysql/mysql_table_view.dart

@@ -233,21 +233,11 @@ class MysqlTableDataDelegate extends TableDataMutationDelegate {
     });
   }
 
+  /// Pooled sessions are shared with every other view of this database, so
+  /// cancelling never closes them: a statement that is still running finishes
+  /// or times out on its own, and the lease is released by [dispose].
   @override
-  void cancel({bool interruptIfBusy = false}) {
-    if (interruptIfBusy) {
-      MysqlService.instance.interrupt(
-        connectionRow,
-        database: database,
-        mode: MysqlSessionMode.readOnly,
-      );
-      MysqlService.instance.interrupt(
-        connectionRow,
-        database: database,
-        mode: MysqlSessionMode.tableWrite,
-      );
-    }
-  }
+  void cancel({bool interruptIfBusy = false}) {}
 
   @override
   void dispose() {

lib/features/postgresql/postgres_table_view.dart

@@ -234,21 +234,11 @@ class PostgresTableDataDelegate extends TableDataMutationDelegate {
     });
   }
 
+  /// Pooled sessions are shared with every other view of this database, so
+  /// cancelling never closes them: a statement that is still running finishes
+  /// or times out on its own, and the lease is released by [dispose].
   @override
-  void cancel({bool interruptIfBusy = false}) {
-    if (interruptIfBusy) {
-      PostgresService.instance.interrupt(
-        connectionRow,
-        database: database,
-        mode: PgSessionMode.readOnly,
-      );
-      PostgresService.instance.interrupt(
-        connectionRow,
-        database: database,
-        mode: PgSessionMode.tableWrite,
-      );
-    }
-  }
+  void cancel({bool interruptIfBusy = false}) {}
 
   @override
   void dispose() {

lib/features/sqlite/sqlite_table_view.dart

@@ -221,19 +221,11 @@ class SqliteTableDataDelegate extends TableDataMutationDelegate {
     });
   }
 
+  /// Pooled sessions are shared with every other view of this database, so
+  /// cancelling never closes them: a statement that is still running finishes
+  /// or times out on its own, and the lease is released by [dispose].
   @override
-  void cancel({bool interruptIfBusy = false}) {
-    if (interruptIfBusy) {
-      SqliteService.instance.interrupt(
-        connectionRow,
-        mode: SqliteSessionMode.readOnly,
-      );
-      SqliteService.instance.interrupt(
-        connectionRow,
-        mode: SqliteSessionMode.tableWrite,
-      );
-    }
-  }
+  void cancel({bool interruptIfBusy = false}) {}
 
   @override
   void dispose() {

lib/features/workspace/generic_table_view.dart

@@ -286,7 +286,8 @@ class GenericTableViewState extends material.State<GenericTableView> {
   void dispose() {
     TableViewCommandBridge.instance.unregister(owner: this);
     _resetStaging();
-    widget.delegate.cancel(interruptIfBusy: true);
+    // Closing the tab releases its lease. It must not interrupt the shared
+    // session: other views of the database may be using it.
     widget.delegate.dispose();
     super.dispose();
   }

test/features/workspace/generic_table_view_relations_test.dart

@@ -86,4 +86,15 @@ void main() {
     await t.pump();
     expect(find.byType(ErdView), findsNothing);
   });
+
+  testWidgets('closing a table tab releases its delegate without cancelling it',
+      (t) async {
+    final delegate = FakeTableDataDelegate();
+    await pumpGenericTableView(t, delegate);
+    await t.pumpWidget(const material.SizedBox());
+    await t.pump();
+    // The session is shared with other views: closing must not interrupt it.
+    expect(delegate.cancelCount, 0);
+    expect(delegate.disposeCount, 1);
+  });
 }