fix(plugin-chart-ag-grid-table): persist Value Aggregation "None" selection (#107166)

The grid-state change detector hashed only column order, sorts and filters,
so changing a column's Value Aggregation (aggFunc) never triggered
onColumnStateChange. On reload the column fell back to its default
initialAggFunc (sum-like), which is why selecting "None" reverted to Sum
while other values appeared to stick.

Extract the signature into getColumnStateSignature() and include per-column
aggFunc, normalizing the "None" case (null/undefined) to a stable sentinel so
the change is captured and persisted. Add unit tests.

superset-frontend/plugins/plugin-chart-ag-grid-table/src/AgGridTable/index.tsx

@@ -57,6 +57,7 @@ import { SearchOption, SortByItem } from '../types';
 import getInitialSortState, { shouldSort } from '../utils/getInitialSortState';
 import getInitialFilterModel from '../utils/getInitialFilterModel';
 import reconcileColumnState from '../utils/reconcileColumnState';
+import getColumnStateSignature from '../utils/getColumnStateSignature';
 import { PAGE_SIZE_OPTIONS } from '../consts';
 import { getCompleteFilterState } from '../utils/filterStateManager';
 
@@ -337,11 +338,11 @@ const AgGridDataTable: FunctionComponent<AgGridTableProps> = memo(
               timestamp: Date.now(),
             };
 
-            const stateHash = JSON.stringify({
-              columnOrder: columnState.map(c => c.colId),
-              sorts: sortModel,
-              filters: filterModel,
-            });
+            const stateHash = getColumnStateSignature(
+              columnState,
+              sortModel,
+              filterModel,
+            );
 
             if (stateHash !== lastCapturedStateRef.current) {
               lastCapturedStateRef.current = stateHash;

superset-frontend/plugins/plugin-chart-ag-grid-table/src/utils/getColumnStateSignature.ts

@@ -0,0 +1,54 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import type { ColumnState } from '@superset-ui/core/components/ThemedAgGridReact';
+
+type SortModelEntry = {
+  colId: string;
+  sort: 'asc' | 'desc';
+  sortIndex: number;
+};
+
+/**
+ * Builds a stable signature of the parts of AG Grid column state that must be
+ * persisted (and therefore must trigger an `onColumnStateChange` when they
+ * change): column order, per-column value aggregation, sorts and filters.
+ *
+ * The value aggregation (`aggFunc`) is normalized so that "no aggregation"
+ * (the AG Grid "None" option, represented as `null`/`undefined`) produces a
+ * distinct, stable signature. Without this, switching a column's Value
+ * Aggregation to "None" did not change the signature, so the change was never
+ * captured and the column reverted to its default aggregation on reload.
+ */
+export default function getColumnStateSignature(
+  columnState: ColumnState[],
+  sortModel: SortModelEntry[],
+  filterModel: Record<string, unknown>,
+): string {
+  return JSON.stringify({
+    columnOrder: columnState.map(col => col.colId),
+    aggregations: columnState.map(col => ({
+      colId: col.colId,
+      // Normalize falsy "None" (null/undefined) to an explicit sentinel so it
+      // is preserved and distinguishable from a real aggregation function.
+      aggFunc: col.aggFunc ?? null,
+    })),
+    sorts: sortModel,
+    filters: filterModel,
+  });
+}

superset-frontend/plugins/plugin-chart-ag-grid-table/test/utils/getColumnStateSignature.test.ts

@@ -0,0 +1,75 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import getColumnStateSignature from '../../src/utils/getColumnStateSignature';
+
+const sortModel: any[] = [];
+const filterModel = {};
+
+test('signature changes when a column value aggregation changes', () => {
+  const before = getColumnStateSignature(
+    [{ colId: 'sales', aggFunc: 'sum' }] as any,
+    sortModel,
+    filterModel,
+  );
+  const after = getColumnStateSignature(
+    [{ colId: 'sales', aggFunc: 'avg' }] as any,
+    sortModel,
+    filterModel,
+  );
+  expect(after).not.toEqual(before);
+});
+
+test('switching value aggregation to "None" (null/undefined) changes the signature', () => {
+  // Regression test for #107166: selecting "None" must be captured so it
+  // persists instead of reverting to the default Sum aggregation on reload.
+  const sumState = getColumnStateSignature(
+    [{ colId: 'sales', aggFunc: 'sum' }] as any,
+    sortModel,
+    filterModel,
+  );
+  const noneNull = getColumnStateSignature(
+    [{ colId: 'sales', aggFunc: null }] as any,
+    sortModel,
+    filterModel,
+  );
+  const noneUndefined = getColumnStateSignature(
+    [{ colId: 'sales' }] as any,
+    sortModel,
+    filterModel,
+  );
+
+  expect(noneNull).not.toEqual(sumState);
+  expect(noneUndefined).not.toEqual(sumState);
+  // null and undefined both represent "None" and must be treated identically.
+  expect(noneNull).toEqual(noneUndefined);
+});
+
+test('signature is stable when nothing changes', () => {
+  const a = getColumnStateSignature(
+    [{ colId: 'sales', aggFunc: 'sum' }] as any,
+    sortModel,
+    filterModel,
+  );
+  const b = getColumnStateSignature(
+    [{ colId: 'sales', aggFunc: 'sum' }] as any,
+    sortModel,
+    filterModel,
+  );
+  expect(a).toEqual(b);
+});