pastilhas
56ca411cf3
The remount table in todo §5.2 was reasoned from the code and never observed, so
this mounts the real WorkspaceRenderer against a mount-counting probe and lets
the real layout-utils mutators produce the "after" tree. Eight cases.
It found one the reading had missed, and it is the cheapest of the lot. ChildEntry
returned `<>{children}</>` for the first child and `<><Handle/>{children}</>` for
every other, so the panel sat in fragment slot 0 when it was first and slot 1
when it was not. Remove the leftmost of three panels and the second one finds a
ResizableHandle in the slot it used to occupy — different element type, so React
unmounts a panel that nothing happened to. Scroll position, media playback, a
transcode, and for a chat panel a re-read of the durable log, all thrown away
because a neighbour was closed. Now the handle slot is always there, holding null
when it is not needed.
The other cases confirm what the doc said but for a different reason. Splitting
against the parent direction, and a two-child group collapsing, both change the
element *type* at that position — PanelSlot becomes ResizablePanelGroup, or the
reverse. React reconciles by type before it looks at keys, so the "reuse the id
so the key doesn't flip" fix the doc proposes would not have moved either one.