[Flight] Fix isValidElement returning false for elements with a debug channel#36136
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976520 wants to merge 1 commit intofacebook:mainfrom
Open
[Flight] Fix isValidElement returning false for elements with a debug channel#36136976520 wants to merge 1 commit intofacebook:mainfrom
976520 wants to merge 1 commit intofacebook:mainfrom
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… channel When `debugChannel` with a readable stream is provided to `createFromNodeStream`, positions 4 (owner) and 5 (stack) in RSC element tuples reference pending debug chunks. The previous code tracked these as blocking deps, which caused elements to be wrapped in `REACT_LAZY_TYPE` via `createLazyChunkWrapper` — breaking `isValidElement()`, `cloneElement()`, and hydration checks. Track debug-only deps (positions 4/5 with an active debug channel) separately in a new `debugDeps` counter on `InitializationHandler`. Only lazy-wrap when there are real blocking deps beyond debug-only ones. After all debug deps resolve, call `initializeElement()` again so `_debugStack` gets normalized from the raw serialized string into an `Error` object, which is required by `captureOwnerStack` / `formatOwnerStack`. Fixes facebook#36097
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Summary
When
debugChannelwith a readable stream is provided tocreateFromNodeStream,positions 4 (owner) and 5 (stack) in RSC element tuples reference pending debug
chunks. The previous code tracked these as blocking deps, which caused elements to
be wrapped in
REACT_LAZY_TYPEviacreateLazyChunkWrapper— breakingisValidElement(),cloneElement(), and hydration checks.Fix: Track debug-only deps (positions 4/5 with an active debug channel) separately
in a new
debugDepscounter onInitializationHandler. Only lazy-wrap when thereare real blocking deps beyond debug-only ones. After all debug deps resolve, call
initializeElement()again so_debugStackgets normalized from the raw serializedstring into an
Errorobject, which is required bycaptureOwnerStack/formatOwnerStack.Fixes #36097
How did you test this change?
Added a regression test in
ReactFlightDOMNode-test.jsthat reproduces the bug:renders a server component through a
debugChannel-backed stream with a delayedtransport, deserializes the result, and asserts
React.isValidElement(deserialized) === true.Also verified the existing
"can transport debug info through a slow debug channel"test continues to pass — the owner stack captured during SSR still correctly reflects
the server-side owner even with the delayed debug channel.