next.js

f93ae7c8 - fix TypeError edge-case for parallel slots rendered multiple times (#64271)

fix TypeError edge-case for parallel slots rendered multiple times (#64271) ### What When rendering a parallel slot multiple times in a single layout, in conjunction with using an error boundary, the following TypeError is thrown: > Cannot destructure property 'parallelRouterKey' of 'param' as it is null ### Why I'm not 100% sure of the reason, but I believe this is because of how React attempts to dededupe (more specifically, "detriplficate") objects that it sees getting passed across the RSC -> client component boundary (and an error boundary is necessarily a client component). When React sees the same object twice, it'll create a reference to that object and then use that reference in future places where it sees the object. My assumption is that there's a bug somewhere here, as the `LayoutRouter` component for the subsequent duplicated parallel slots (after the first one) have no props, hence the TypeError. ### How Rather than passing the error component as a prop to `LayoutRouter`, this puts it as part of the `CacheNodeSeedData` data structure. This is more aligned with other properties anyway (such as `loading` and `rsc` for each segment), and seems to work around this bug as the `initialSeedData` prop is only passed from RSC->client once. EDIT: Confirmed this is also fixed after syncing the latest React, due to https://github.com/facebook/react/pull/28669 Fixes #58485 Closes NEXT-2095