fix(sqllab): prevent unwanted tab switching when autocompleting table names on SQL Lab (#35992)

superset-frontend/src/SqlLab/reducers/sqlLab.test.js

@@ -370,6 +370,93 @@ describe('sqlLabReducer', () => {
       newState = sqlLabReducer(newState, action);
       expect(newState.tables).toHaveLength(0);
     });
+    test('should set activeSouthPaneTab when adding expanded table', () => {
+      const expandedTable = {
+        ...table,
+        id: 'expanded_table_id',
+        name: 'expanded_table',
+        expanded: true,
+      };
+      const action = {
+        type: actions.MERGE_TABLE,
+        table: expandedTable,
+      };
+      newState = sqlLabReducer(initialState, action);
+      expect(newState.tables).toHaveLength(1);
+      expect(newState.activeSouthPaneTab).toBe(expandedTable.id);
+    });
+    test('should not set activeSouthPaneTab when adding collapsed table', () => {
+      const collapsedTable = {
+        ...table,
+        id: 'collapsed_table_id',
+        name: 'collapsed_table',
+        expanded: false,
+      };
+      const action = {
+        type: actions.MERGE_TABLE,
+        table: collapsedTable,
+      };
+      newState = sqlLabReducer(initialState, action);
+      expect(newState.tables).toHaveLength(1);
+      expect(newState.activeSouthPaneTab).toBe(initialState.activeSouthPaneTab);
+    });
+    test('should set activeSouthPaneTab when merging existing table with expanded=true', () => {
+      // First add a table with expanded=false
+      const collapsedTable = {
+        ...table,
+        id: 'existing_table_id',
+        name: 'existing_table',
+        expanded: false,
+      };
+      const addAction = {
+        type: actions.MERGE_TABLE,
+        table: collapsedTable,
+      };
+      newState = sqlLabReducer(initialState, addAction);
+      const previousActiveSouthPaneTab = newState.activeSouthPaneTab;
+
+      // Now merge the same table with expanded=true
+      const expandedTable = {
+        ...collapsedTable,
+        expanded: true,
+      };
+      const mergeAction = {
+        type: actions.MERGE_TABLE,
+        table: expandedTable,
+      };
+      newState = sqlLabReducer(newState, mergeAction);
+      expect(newState.tables).toHaveLength(1);
+      expect(newState.activeSouthPaneTab).toBe(expandedTable.id);
+      expect(newState.activeSouthPaneTab).not.toBe(previousActiveSouthPaneTab);
+    });
+    test('should not set activeSouthPaneTab when merging existing table with expanded=false', () => {
+      // First add a table with expanded=true
+      const expandedTable = {
+        ...table,
+        id: 'existing_table_id_2',
+        name: 'existing_table_2',
+        expanded: true,
+      };
+      const addAction = {
+        type: actions.MERGE_TABLE,
+        table: expandedTable,
+      };
+      newState = sqlLabReducer(initialState, addAction);
+      expect(newState.activeSouthPaneTab).toBe(expandedTable.id);
+
+      // Now merge the same table with expanded=false
+      const collapsedTable = {
+        ...expandedTable,
+        expanded: false,
+      };
+      const mergeAction = {
+        type: actions.MERGE_TABLE,
+        table: collapsedTable,
+      };
+      newState = sqlLabReducer(newState, mergeAction);
+      expect(newState.tables).toHaveLength(1);
+      expect(newState.activeSouthPaneTab).toBe(expandedTable.id);
+    });
   });
   // eslint-disable-next-line no-restricted-globals -- TODO: Migrate from describe blocks
   describe('Run Query', () => {