[Bug] Cannot read properties of undefined (reading 'group') in blurSeries during React re-render

[davesecops]

Version

6.0.0

Link to Minimal Reproduction

N/A — race condition during React component re-render

Steps to Reproduce

1. Render an ECharts chart (Sankey, Bar, Treemap) inside a React component
2. Use notMerge: true with echarts-for-react
3. Trigger a data change that causes React to re-render the chart (e.g., toggling filter buttons)
4. While the chart is re-rendering, move the mouse over the chart area

Current Behavior

Runtime TypeError:

Cannot read properties of undefined (reading 'group')

Stack trace:

blurSeries (echarts/lib/util/states.js:362)
  → var view = api.getViewOfSeriesModel(seriesModel);
  → view.group.traverse(...)  // 💥 view is undefined

handleGlobalMouseOverForHighDown (states.js:499)
Handler.<anonymous> (echarts.js:1549)
Eventful.trigger (zrender/Eventful.js:103)
Handler.dispatchToElement (zrender/Handler.js:148)
Handler.mousemove (zrender/Handler.js:101)
HandlerDomProxy.mousemove (zrender/HandlerProxy.js:90)
HTMLDivElement.<anonymous> (zrender/HandlerProxy.js:209)

Expected Behavior

No crash. The blur effect should be skipped gracefully when the series view has been disposed.

Root Cause

In blurSeries() (src/util/states.ts), api.getViewOfSeriesModel(seriesModel) can return undefined when a series model still exists in the GlobalModel but its view has been disposed during a React re-render cycle (via setOption with notMerge or component unmount). The code unconditionally accesses view.group:

const view = api.getViewOfSeriesModel(seriesModel);
view.group.traverse(function (child) {  // ← crashes if view is undefined

This is the same class of bug as #9402 and #21535 — stale references to disposed series during mouse events.

Suggested Fix

Add a null guard after the view lookup:

const view = api.getViewOfSeriesModel(seriesModel);
if (!view || !view.group) {
    return;
}
view.group.traverse(function (child) {

This follows the same pattern used elsewhere in the codebase (e.g., toggleSeriesBlurState already guards view access).

I will submit a PR with this fix.

Environment

Item	Value
OS	macOS
Browser	Chrome
Framework	React 19 + Next.js 16
echarts-for-react	3.0.6