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base repository: facebook/react
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  • 4 commits
  • 4 files changed
  • 2 contributors

Commits on Jul 31, 2025

  1. [Fizz] Don't outline Boundaries that may contribute to the preamble (#… 

    …34058)

Suspense boundaries that may have contributed to the preamble should not
be outlined due to size because these boundaries are only meant to be in
fallback state if the boundary actually errors. This change excludes any
boundary which has the potential to contribute to the preamble. We could
alternatively track which boundaries actually contributed to the
preamble but in practice there will be very few and I think this is
sufficient.

One problem with this approach is it makes Suspense above body opt out
of the mode where we omit rel="expect" for large shells. In essence
Suspense above body has the semantics of a Shell (it blocks flushing
until resolved) but it doesn't get tracked as request bytes and thus we
will not opt users into the skipped blocking shell for very large
boundaries.

This will be fixed in a followup
    @gnoff
    gnoff authored Jul 31, 2025
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  2. [Fizz] Count Boundary bytes that may contribute to the preamble in th… 

    …e request byteSize (#34059)

Stacked on #34058

When tracking how large the shell is we currently only track the bytes
of everything above Suspense boundaries. However since Boundaries that
contribute to the preamble will always be inlined when the shell flushes
they should also be considered as part of the request byteSize since
they always flush alongside the shell. This change adds this tracking
    @gnoff
    gnoff authored Jul 31, 2025
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  3. [DevTools] Model Hidden Offscreen Boundaries as Unmounts (#34062) 

    This is modeling Offscreen boundaries as the thing that unmounts a tree
in the frontend. This will let us model this as a "hide" that preserves
state instead in a follow up but not yet.

By doing it this way, we don't have to special case suspended Suspense
boundaries, at least not for the modern versions that use Offscreen as
the internal node. It's still special cased for the old React versions.
Instead, this is handled by the Offscreen fiber getting hidden.

By giving this fiber an FilteredFiberInstance, we also have somewhere to
store the children on (separately from the parent children set which can
include other siblings too like the loading state).

One consequence is that Activity boundary content now disappears when
they're hidden which is probably a good thing since otherwise it would
be confusing and noisy when it's used to render multiple pages at once.
    @sebmarkbage
    sebmarkbage authored Jul 31, 2025
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  4. [DevTools] Clean up Virtual Instances from id map (#34063) 

    This was a pretty glaring memory leak. 🙈

I forgot to clean up the VirtualInstances from the id map so the Server
Component instances always leaked in DEV.
    @sebmarkbage
    sebmarkbage authored Jul 31, 2025
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