[Flight] Avoid unnecessary indirection when serializing debug info #34797
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When a debug channel is hooked up, and we're serializing debug models,
if the result is an already outlined reference, we can emit it directly,
without also outlining the reference. This would create an unnecessary
indirection.
Before:
```
:N1760023808330.2688
0:D"$2"
0:D"$3"
0:D"$4"
0:"hi"
1:{"name":"Component","key":null,"env":"Server","stack":[],"props":{}}
2:{"time":3.0989999999999327}
3:"$1"
4:{"time":3.261792000000014}
```
After:
```
:N1760023786873.8916
0:D"$2"
0:D"$1"
0:D"$3"
0:"hi"
1:{"name":"Component","key":null,"env":"Server","stack":[],"props":{}}
2:{"time":2.4145829999999933}
3:{"time":2.5488749999999527}
```
Notice how the second debug info chunk is now directly referencing chunk
`1` in the debug channel, without outlining and referencing `"$1"` as
its own debug chunk `3`.
This not only simplifies the RSC payload, and reduces overhead. But more
importantly it helps the client resolve cyclic references when a model
has debug info that has a reference back to the model. The client is
currently not able to resolve such a cycle when those chunk indirections
are involved. Ideally, we would also be able to resolve them regardless,
but that requires more work. In the meantime, this fixes an immediate
issue.
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Oct 10, 2025
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…acebook#34797) When a debug channel is hooked up, and we're serializing debug models, if the result is an already outlined reference, we can emit it directly, without also outlining the reference. This would create an unnecessary indirection. Before: ``` :N1760023808330.2688 0:D"$2" 0:D"$3" 0:D"$4" 0:"hi" 1:{"name":"Component","key":null,"env":"Server","stack":[],"props":{}} 2:{"time":3.0989999999999327} 3:"$1" 4:{"time":3.261792000000014} ``` After: ``` :N1760023786873.8916 0:D"$2" 0:D"$1" 0:D"$3" 0:"hi" 1:{"name":"Component","key":null,"env":"Server","stack":[],"props":{}} 2:{"time":2.4145829999999933} 3:{"time":2.5488749999999527} ``` Notice how the second debug info chunk is now directly referencing chunk `1` in the debug channel, without outlining and referencing `"$1"` as its own debug chunk `3`. This not only simplifies the RSC payload, and reduces overhead. But more importantly it helps the client resolve cyclic references when a model has debug info that has a reference back to the model. The client is currently not able to resolve such a cycle when those chunk indirections are involved. Ideally, it would also be able to resolve them regardless, but that requires more work. In the meantime, this fixes an immediate issue. DiffTrain build for [ead9218](facebook@ead9218)
github-actions bot
pushed a commit
to Meet-student/react
that referenced
this pull request
Oct 11, 2025
…acebook#34797) When a debug channel is hooked up, and we're serializing debug models, if the result is an already outlined reference, we can emit it directly, without also outlining the reference. This would create an unnecessary indirection. Before: ``` :N1760023808330.2688 0:D"$2" 0:D"$3" 0:D"$4" 0:"hi" 1:{"name":"Component","key":null,"env":"Server","stack":[],"props":{}} 2:{"time":3.0989999999999327} 3:"$1" 4:{"time":3.261792000000014} ``` After: ``` :N1760023786873.8916 0:D"$2" 0:D"$1" 0:D"$3" 0:"hi" 1:{"name":"Component","key":null,"env":"Server","stack":[],"props":{}} 2:{"time":2.4145829999999933} 3:{"time":2.5488749999999527} ``` Notice how the second debug info chunk is now directly referencing chunk `1` in the debug channel, without outlining and referencing `"$1"` as its own debug chunk `3`. This not only simplifies the RSC payload, and reduces overhead. But more importantly it helps the client resolve cyclic references when a model has debug info that has a reference back to the model. The client is currently not able to resolve such a cycle when those chunk indirections are involved. Ideally, it would also be able to resolve them regardless, but that requires more work. In the meantime, this fixes an immediate issue. DiffTrain build for [ead9218](facebook@ead9218)
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When a debug channel is hooked up, and we're serializing debug models, if the result is an already outlined reference, we can emit it directly, without also outlining the reference. This would create an unnecessary indirection.
Before:
After:
Notice how the second debug info chunk is now directly referencing chunk
1in the debug channel, without outlining and referencing"$1"as its own debug chunk3.This not only simplifies the RSC payload, and reduces overhead. But more importantly it helps the client resolve cyclic references when a model has debug info that has a reference back to the model. The client is currently not able to resolve such a cycle when those chunk indirections are involved. Ideally, it would also be able to resolve them regardless, but that requires more work. In the meantime, this fixes an immediate issue.