fix(tooltip): guard against removed series in cached axis tooltip params (Fixes #21732)

[waterWang]

Fixes #21732

Problem

TooltipView._showAxisTooltip iterates axisItem.seriesDataIndices whose seriesIndex values come from the cached pointer state (_lastDataByCoordSys). When a merged setOption removes series (e.g. replaceMerge: ['series', ...]) while the tooltip is still showing, those cached indices become stale and ecModel.getSeriesByIndex(idxItem.seriesIndex) returns undefined, causing:

Uncaught TypeError: Cannot read properties of undefined (reading 'getDataParams')
    at TooltipView._showAxisTooltip

Root cause

1. TooltipView caches the last hovered pointer state in _lastX / _lastY / _lastDataByCoordSys.
2. Every setOption runs TooltipView.render() → _keepShow(), which re-shows the tooltip with the cached dataByCoordSys after the update.
3. The new option has fewer series than the cached indices refer to → getSeriesByIndex returns undefined → series.getDataParams(...) throws.

Fix

Two defensive guards in _showAxisTooltip:

1. Skip stale seriesDataIndices entries whose series no longer exists: if (!series) { return; }
2. Move the existing !axisModel guard before the axisModel.axis access (it was previously checked after being dereferenced), so a removed axis also short-circuits instead of crashing.

Test

With tooltip: {trigger: 'axis'}, hover to show the tooltip, then setOption with fewer series in merge mode — the tooltip no longer throws and safely skips removed series.

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[Copilot]

🟡 Changes recommended

Cached tooltip content can remain stale, and regression coverage is missing.

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Pull request overview

Hardens cached axis-tooltip refreshes after merged updates remove axes or series.

Changes:

• Guards missing axis models before dereferencing.
• Skips stale series references during tooltip generation.
• Adds defensive handling, but cached tooltip content may remain stale.

File summaries

File	Review summary
src/component/tooltip/TooltipView.ts	Adds axis and series guards. Two moderate findings remain about stale cached content, plus one nit requesting regression coverage.

Review details

Suppressed comments (2)

src/component/tooltip/TooltipView.ts:558

• This short-circuit avoids the null dereference, but it leaves _lastDataByCoordSys pointing at the same cached data. _updateContentNotChangedOnAxis can therefore compare the cache against itself, return true, and only move the existing tooltip instead of rebuilding it; the tooltip can continue displaying the removed axis's old content. Mark the cached content invalid when this guard fires so the tooltip is rebuilt or hidden.

                if (!axisModel || axisValue == null) {

src/component/tooltip/TooltipView.ts:583

• Please add a regression case for the cached axis-tooltip path: keep the pointer over a chart with several series, then call merged setOption with replaceMerge: ['series', 'xAxis', 'yAxis'] so the asynchronous _keepShow callback processes stale indices. The repository has browser tooltip/setOption cases, but this change adds no coverage for the uncaught stale-series/removed-axis scenario, so this guard could regress unnoticed.

                    if (!series) {
                        return;
                    }

• Files reviewed: 1/1 changed files
• Comments generated: 1
• Review effort level: Lite

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