From b0a5fb2efcc9cb51235633ce7ffdf010cce24f00 Mon Sep 17 00:00:00 2001
From: aloktomarr <aloktomar055@gmail.com>
Date: Fri, 17 Jul 2026 18:21:20 +0530
Subject: [PATCH] fix(marker): skip invalid markLine data items instead of
 crashing the render. close #21683

---
 src/component/marker/MarkLineView.ts          |  7 ++
 .../ut/spec/component/marker/MarkLine.test.ts | 67 +++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 test/ut/spec/component/marker/MarkLine.test.ts

diff --git a/src/component/marker/MarkLineView.ts b/src/component/marker/MarkLineView.ts
index 9ee9aa43d0..2a1092e48b 100644
--- a/src/component/marker/MarkLineView.ts
+++ b/src/component/marker/MarkLineView.ts
@@ -175,6 +175,13 @@ function markLineFilter(
     coordSys: CoordinateSystem,
     item: MarkLine2DDataItemOption
 ) {
+    // An invalid entry in `markLine.data` (e.g. an empty object `{}`) is
+    // normalized to undefined endpoints. Such a markLine cannot be drawn, so
+    // drop it here instead of dereferencing `undefined.coord` and throwing,
+    // which would abort rendering of all the other markLines. See #21683.
+    if (!item[0] || !item[1]) {
+        return false;
+    }
     if (coordSys.type === 'cartesian2d') {
         const fromCoord = item[0].coord;
         const toCoord = item[1].coord;
diff --git a/test/ut/spec/component/marker/MarkLine.test.ts b/test/ut/spec/component/marker/MarkLine.test.ts
new file mode 100644
index 0000000000..479d5e38b9
--- /dev/null
+++ b/test/ut/spec/component/marker/MarkLine.test.ts
@@ -0,0 +1,67 @@
+/*
+* 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, getECModel } from '../../../core/utHelper';
+import { EChartsType } from '../../../../../src/echarts';
+import MarkerModel from '../../../../../src/component/marker/MarkerModel';
+
+describe('component/markLine', function () {
+
+    let chart: EChartsType;
+    beforeEach(function () {
+        chart = createChart();
+    });
+
+    afterEach(function () {
+        chart.dispose();
+    });
+
+    // Regression test for #21683: an empty/invalid entry (e.g. `{}`) inside
+    // `markLine.data` used to throw "Cannot read properties of undefined
+    // (reading 'coord')" in markLineFilter, which aborted rendering of ALL
+    // markLines. It should instead be ignored while the valid markLines render.
+    it('ignores an empty markLine data item and still renders the valid ones (#21683)', function () {
+        function setInvalidMarkLine() {
+            chart.setOption({
+                xAxis: { type: 'category', data: ['A', 'B', 'C', 'D', 'E'] },
+                yAxis: { type: 'value' },
+                series: [{
+                    type: 'bar',
+                    data: [1, 2, 3, 4, 5],
+                    markLine: {
+                        data: [
+                            { yAxis: 1 },
+                            {}, // invalid / empty entry
+                            { yAxis: 3 }
+                        ]
+                    }
+                }]
+            });
+        }
+
+        expect(setInvalidMarkLine).not.toThrow();
+
+        // The two valid markLines should still be rendered; the empty one dropped.
+        const seriesModel = getECModel(chart).getSeriesByIndex(0);
+        const markLineModel = MarkerModel.getMarkerModelFromSeries(seriesModel, 'markLine');
+        expect(markLineModel).toBeTruthy();
+        expect(markLineModel.getData().count()).toBe(2);
+    });
+
+});