fix: per-instance tooltip render-object registry to stop two-tooltip hit-test crash - #660
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…t crash
Tooltip child layout was coordinated through a process-wide static map,
`RenderObjectManager.renderObjects`, keyed only by TooltipLayoutSlot
(tooltipBox / actionBox / arrow). `_RenderPositionDelegate.performLayout`
registers its children into that map, lays them out through it, then clears
it. When two tooltips are alive at the same time — e.g. one dismissing while
the next starts, or a lingering overlay — their layouts share the one map and
clobber each other's slots. With asserts disabled (release), a clobbered
delegate skips laying out its own children yet still sizes itself to
`constraints.biggest` (the full screen), so the next pointer event hit-tests a
never-laid-out child and crashes in RenderBox.hitTest ("Cannot hit test a
render box that has never been laid out", `_size!`). Two nested
`_RenderPositionDelegate.hitTestChildren` frames in the crash stack are the
signature of two simultaneously-live tooltips.
Fixes:
- Move the slot->RenderObjectManager map onto each `_RenderPositionDelegate`
instance (`_renderObjects` + `_managerFor`), so two delegates can never see
or overwrite each other's children. Drops the `static renderObjects` map,
`static clear()`, and the `TooltipLayoutSlot.getObjectManager` extension.
- Harden `_RenderPositionDelegate.hitTestChildren` to skip any child that was
never laid out (`child.hasSize`). This mirrors `defaultHitTestChildren`; in a
healthy single-tooltip layout every child has a size so it is a no-op, and it
turns any residual never-laid-out hit test into a harmless miss instead of a
crash.
Related to the two-simultaneous-showcases family in issue SimformSolutionsPvtLtd#563.
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Problem
RenderBox.hitTestthrows a fatalFlutterError("Cannot hit test a render box that has never been laid out", i.e._size!on a null size) when two tooltips are alive at the same time — e.g. one showcase being dismissed as the next one starts, or a lingering overlay. In our crash reports the signature is two nested_RenderPositionDelegate.hitTestChildrenframes in the hit-test stack. This is the same family as #563 (two simultaneous showcases).Root cause
Tooltip child layout is coordinated through a process-wide
staticmap,RenderObjectManager.renderObjects, keyed only byTooltipLayoutSlot(tooltipBox/actionBox/arrow):_RenderPositionDelegate.performLayout()calls_identifyChildren(), which registers each child into the static map, lays the children out through it, then callsRenderObjectManager.clear()._RenderPositionDelegateexists at the same time, the two share that one map and clobber each other's slots.constraints.biggest(the full screen). The next pointer event then hit-tests a never-laid-out child and crashes.Fix
Per-instance registry. Move the slot →
RenderObjectManagermap off thestaticfield and onto each_RenderPositionDelegateinstance (_renderObjects+_managerFor(slot)). Two delegates can no longer see or overwrite each other's children. This removes thestatic renderObjectsmap,static clear(), and theTooltipLayoutSlot.getObjectManagerextension getter.Defensive hit-test guard.
_RenderPositionDelegate.hitTestChildrennow skips any child that was never laid out (child.hasSize). It mirrorsdefaultHitTestChildren, so in a healthy single-tooltip layout every child has a size and it behaves identically; it only matters during a transient overlap, where it turns a hard crash into a harmless missed hit on a tooltip that is on its way out.No public API changes to
Showcase/ShowcaseView. The removed symbols (RenderObjectManager.renderObjects,.clear(),TooltipLayoutSlot.getObjectManager) are internal to the tooltip layout system.