fix(mapbox): guard against null viewport when canvas has zero dimensions

[chrisgervang]

Fixes issue observed in #10075

When a Mapbox/MapLibre map container is hidden or detached, the deck.gl canvas can have zero width or height.

In that case, view.makeViewport() returns null, and drawLayer/drawLayerGroup were passing that null directly into deck._drawLayers() as the viewport, causing a crash.
The fix adds an early return in both drawLayer and drawLayerGroup when the viewport is null.

A regression test was added that forces deck.width and deck.height to zero before triggering a render, verifying no error is thrown.

https://claude.ai/code/session_01QMHj3ie96cqTLwVYxWwSXo

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Note

Low Risk
Low risk defensive change in Mapbox rendering: it only short-circuits drawing when getViewport() returns null, preventing a crash when the canvas has 0×0 dimensions.

Overview
Prevents crashes in Mapbox/MapLibre integration when the deck.gl canvas is hidden/detached (0×0), by early-returning in drawLayer and drawLayerGroup when getViewport() returns null instead of passing a null viewport into deck._drawLayers().

Tests were hardened to surface render exceptions (mock map captures _renderError), and new regression specs cover both MapboxLayer#drawLayer and the afterRender path under a zero-size canvas to ensure renders do not throw.

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[cursor]

Stale _renderError never cleared between render calls

Low Severity

_renderError is only ever assigned on failure and never reset to null/undefined at the start of _render(). If _render() is called multiple times (e.g., via multiple triggerRepaint() calls queued by Deck's _customRender), an error from an earlier render persists even if a later render succeeds. The t.notOk(_renderError) assertion in the render handler would then report a stale error, producing a misleading or false test failure. Adding this._renderError = null before the try-catch would ensure the value always reflects the most recent render attempt.

 

[coveralls]

coverage: 91.003% (-0.002%) from 91.005%
when pulling b03d72e on claude/fix-mapbox-null-viewport-nsDGF
into 01f071e on master.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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