Retain source Image/Canvas in CanvasPattern so the cairo surface stays valid#2583
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iurisilvio wants to merge 1 commit into
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Retain source Image/Canvas in CanvasPattern so the cairo surface stays valid#2583iurisilvio wants to merge 1 commit into
iurisilvio wants to merge 1 commit into
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…s valid Pattern stores a cairo_pattern_t* created from a source Image or Canvas via cairo_pattern_create_for_surface(). The pattern references the cairo surface internally but does not retain the JS source object. If the source is garbage-collected, Canvas::destroySurface() calls cairo_surface_finish(_surface) followed by cairo_surface_destroy(_surface). A finished surface is no longer a valid live backing store for pattern rendering, even if cairo still holds a reference to it via the pattern. The bug is reliably reproducible when finalizers run promptly (e.g. with NAPI_EXPERIMENTAL enabled and node_api_post_finalizer in use); without that path, the source typically survives long enough by accident. Fix: hold a Napi::Reference to the source JS object in Pattern and reset it from Pattern::Finalize(). Fixes Automattic#2579
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Fixes #2579.
Pattern(the C++ class behindCanvasPattern) stores acairo_pattern_t*created from a sourceImageorCanvas, but it doesn't retain the JS source object. When the source is garbage-collected,Canvas::destroySurface()callscairo_surface_finishfollowed bycairo_surface_destroy— a finished surface is no longer a valid live backing store for pattern rendering, even though the cairo pattern still holds a reference to it.The bug becomes reliably reproducible when finalizers run promptly (e.g. with
NAPI_EXPERIMENTALenabled andnode_api_post_finalizerrunning the finalizer at a safe point); without that path, the source typically survives long enough by accident.Fix: hold a
Napi::Reference<Napi::Object>to the source JS object inPatternand reset it fromPattern::Finalize(). Repro in #2579.