From 358915d30de95c4399542905585385ec8c0dd803 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bogus=C5=82aw=20Skrzypkowiak?=
 <228489+b091@users.noreply.github.com>
Date: Mon, 12 Oct 2026 15:35:55 +0400
Subject: [PATCH] fix(universalTransition): skip array seriesKey members
 missing from the old series

When a series declares an array seriesKey and its members change between updates (e.g. a pie whose categories shrink after filtering), findTransitionSeriesBatches looked up each member in oldDataMap and dereferenced undefined. The throw also skipped saving the old series, so every later update threw again.
---
 src/animation/universalTransition.ts |  2 +-
 test/ut/spec/series/pie.test.ts      | 58 ++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 test/ut/spec/series/pie.test.ts

diff --git a/src/animation/universalTransition.ts b/src/animation/universalTransition.ts
index a87668d336..c3b28875f1 100644
--- a/src/animation/universalTransition.ts
+++ b/src/animation/universalTransition.ts
@@ -623,7 +623,7 @@ function findTransitionSeriesBatches(
                     const oldSeries: TransitionSeries[] = [];
                     each(transitionKey, key => {
                         const oldData = oldDataMap.get(key);
-                        if (oldData.data) {
+                        if (oldData && oldData.data) {
                             oldSeries.push({
                                 dataGroupId: oldData.dataGroupId,
                                 divide: getDivideShapeFromData(oldData.data),
diff --git a/test/ut/spec/series/pie.test.ts b/test/ut/spec/series/pie.test.ts
new file mode 100644
index 0000000000..b5aafcab77
--- /dev/null
+++ b/test/ut/spec/series/pie.test.ts
@@ -0,0 +1,58 @@
+/*
+* 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 { createChart, removeChart } from '../../core/utHelper';
+import { EChartsType } from '@/src/echarts';
+
+describe('pie universalTransition', function () {
+
+    let chart: EChartsType;
+    beforeEach(function () {
+        chart = createChart({ width: 400, height: 300 });
+    });
+
+    afterEach(function () {
+        removeChart(chart);
+    });
+
+    function pieWithSeriesKey(groups: string[]) {
+        return {
+            series: [{
+                type: 'pie',
+                universalTransition: {
+                    enabled: true,
+                    seriesKey: groups.map(group => 'metric-' + group)
+                },
+                data: groups.map((group, idx) => ({ name: group, value: idx + 1 }))
+            }]
+        };
+    }
+
+    // An array seriesKey whose members no longer match the previous update (e.g. a pie whose
+    // categories shrink after filtering) must skip the transition instead of throwing.
+    it('should not throw when an array seriesKey has members missing from the old series', function () {
+        chart.setOption(pieWithSeriesKey(['A', 'B']));
+
+        expect(() => chart.setOption(pieWithSeriesKey(['B']), { replaceMerge: ['series'] })).not.toThrow();
+        // The old series snapshot must be refreshed too, or every later update throws again.
+        expect(() => chart.setOption(pieWithSeriesKey(['B']), { replaceMerge: ['series'] })).not.toThrow();
+        expect((chart as any).getModel().getSeriesByIndex(0).getData().count()).toBe(1);
+    });
+
+});