Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53071
Changelog: [internal]
The current API to take JS heap snapshots has some problems:
1. Ergonomics: it requires you to input the filepath where you want to store the snapshot. This isn't aligned with the behavior we have for JS traces where the output path is provided to you.
2. It doesn't work in optimized builds, as it requires a specific option in Hermes.
For 1), this replaces `Fantom.saveJSMemoryHeapSnapshot(filePath)` with `Fantom.takeJSMemoryHeapSnapshot()` that outputs the snapshot in a predefined path and prints it to the console.
For 2), this adds a new environment variable to force building Hermes with memory instrumentation (`FANTOM_ENABLE_JS_MEMORY_INSTRUMENTATION`). This is exposed as an option and not set by default because it has a performance overhead at runtime that we don't want to pay (especially in benchmarks).
This option only works when using Buck in development, because we want to generate this new binary type on demand when necessary, instead of making it part of the prebuilts we do before running tests in OSS and CI.
Reviewed By: lenaic
Differential Revision: D79642314
fbshipit-source-id: a2980616a495bd6dca29c0709a9581db6fb3f2cc
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53069
Changelog: [internal]
This changes the names of the JS traces from Fantom from using a unix timestamp in the file name to using the ISO date:
- From: `View-itest.js-1754406329686.cpuprofile`
- To: `View-itest.js-2025-08-05T15:05:29.686Z.cpuprofile`
Reviewed By: rshest
Differential Revision: D79646760
fbshipit-source-id: d8a654724c1abc2d3e285ee658c2d390d3241d82
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53091
# Changelog:
[Internal] -
This fixes some excessive printing from the benchmarking results, which happened even if there was no benchmarks ran.
Reviewed By: rubennorte
Differential Revision: D79719026
fbshipit-source-id: 0e75d97ae9c762cab25007bfab5ca8a6dc43e148
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53070
As per title, this change adds a warning if you call `pod install` with `RCT_NEW_ARCH_ENABLED` set to 0.
## Changelog:
[iOS][Added] - Add warning if RCT_NEW_ARCH_ENABLED is set to 0
Reviewed By: mdvacca
Differential Revision: D79655716
fbshipit-source-id: 516cc02f9b2dbddaae99c2d74bba249970641d1d
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53065
Instead of checking results from the previous day, allow to go back up to 7
days in the past to check for previous runs.
Changelog:
[Internal] [Changed] -
Reviewed By: cipolleschi
Differential Revision: D79568067
fbshipit-source-id: 5d6fac6a06b4e26e52de6fbf6187ec8f8e44e10e
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53066
This diff introduces the mechanism for us to store the result of nightly 3p
library integration on Firebase.
Having the result store, we can now query the result from the previous day and
report if the build is newly broken or recovered overnight.
Changelog:
[Internal] [Changed] -
Reviewed By: cipolleschi
Differential Revision: D79565536
fbshipit-source-id: ba839b2950462a7ca6186a163f93f062719304fb
Summary:
Pure cocoapods build with dyn frameworks was broken due to some missing dependencies with the new performance metrics of cdp
## Changelog:
[iOS][Fixed] - Fix pure cocoapods dynamic framework build
Pull Request resolved: https://github.com/facebook/react-native/pull/53075
Test Plan:
Tested locally in RNTester with
```
USE_FRAMEWORKS=dynamic bundle exec pod install
```
and then building from Xcode
Reviewed By: cortinico
Differential Revision: D79676186
Pulled By: cipolleschi
fbshipit-source-id: ae6b81138fcae66c67bedadb1e1ad9cd6c4b6c35
Summary:
Add filter to native animated allowlist.
## Changelog:
[GENERAL] [ADDED] - Allow filter usage with native animated driver.
<!-- Help reviewers and the release process by writing your own changelog entry.
Pick one each for the category and type tags:
For more details, see:
https://reactnative.dev/contributing/changelogs-in-pull-requests
Pull Request resolved: https://github.com/facebook/react-native/pull/52920
Test Plan: Tested on RNTester
Reviewed By: joevilches
Differential Revision: D79473929
Pulled By: lunaleaps
fbshipit-source-id: de6fcc0f18a1d656688dce513d2cf48a3c9d4f09
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53057
Changelog: [internal]
This adds a Fantom test to ensure that `setUpDefaultReactNativeEnvironment` doesn't read any feature flags. This prevents catching this as a runtime issue when the feature flag system complains that feature flags were accessed before being overridden, which always would happen if this module read any flags (as it runs before any product code that sets overrides).
Reviewed By: rshest
Differential Revision: D79639890
fbshipit-source-id: 6997609b7bf84947a6da53b58e68f9edd5654912
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53056
Changelog: [internal]
This exposes a utility method in `ReactNativeFeatureFlagsBase` to reset its internal state for testing purposes.
This is intentionally not exposed through `ReactNativeFeatureFlags` to avoid it being used at runtime.
Reviewed By: rshest
Differential Revision: D79639889
fbshipit-source-id: adfb6125d991994c9706d5952d309915fec8f815
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53026
This change prevents users from opting out of the New Architecure.
The change is non breaking with respect to building an app: all the functions are still there, even if they are unreachable, in case users will still call them explicitly.
We hardcoded all the values to enable the New Architecture, so there is no way to disable it.
This is a behavioral breaking change, though.
## Changelog:
[iOS][Removed] - Removed the opt-out from the New Architecture.
Reviewed By: cortinico
Differential Revision: D79090048
fbshipit-source-id: 9779bfedf50748d7adbef5f7ef038f469e30efc2
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53063
Update `IO.read` CDP method handler to validate the received `size` parameter.
This now accepts a max value of 10MB — adding a layer of safety in front of our current Android implementation, which fails at around ~15MB due to OkHttp limits.
Changelog: [Internal]
Reviewed By: vzaidman
Differential Revision: D79646155
fbshipit-source-id: c777802105dc31cdcc7e9e960c880e689540fddd
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53003
The new `onChildStartedNativeGesture` method accepts a nullable `ReactContext` value for the purpose of flushing active touch events. This change updates all callsites of that method to pass a `ReactContext`
Changelog: [Internal]
Reviewed By: mdvacca
Differential Revision: D79258727
fbshipit-source-id: 7b2950f514295dbe26822442c98079b8121cb3bf
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52925
# Changelog:
[Internal] -
This adds an extra "ranking" report when running Fantom benchmark vs different React Feature flag configurations.
It can be very useful when implementing some particular optimization, to streamline the before/after comparison wit this optimization enabled/disabled.
Reviewed By: andrewdacenko
Differential Revision: D79269601
fbshipit-source-id: f29e761e313d6857e5b3ac65faf2a387a84be9df
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53053
Changelog: [internal]
This adds a Fantom test to ensure that setting up the RN environment doesn't trigger the initialization for React components like View and Text, which should be lazy loaded when necessary.
Reviewed By: rshest
Differential Revision: D79636160
fbshipit-source-id: ef1fbd6cd531eb7082dce000ba74a5eed451e259
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53054
Changelog: [internal]
We eagerly require `AppRegistry` from environment initialization (`InitializeCore`) because it has some side-effects that are necessary for error reporting (see https://github.com/facebook/react-native/issues/34649 and https://github.com/facebook/react-native/pull/34650), but this change makes a lot of modules to be eagerly initialized.
This reduces that to avoid loading modules that not necessary for environment setup, which allows us to do things like setting up feature flags before modules like `View` and `Text` have been initialized.
Reviewed By: rshest
Differential Revision: D79636159
fbshipit-source-id: a3f1e0db3dd69112ceef3ea339167694e2457454
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52827
Changelog: [internal]
This adds **support for creating Hermes/JS sampling profiler traces in Fantom**, which is especially useful when running benchmarks.
Usage:
```
FANTOM_PROFILE_JS=1 yarn fantom Animated-benchmark
```
Output:
{F1980642216}
After this, the trace is fully symbolicated.
Can be opened directly in Google Chrome:
{F1980642229}
Or in the built-in viewer in VSCode:
{F1980642242} {F1980642240} {F1980642241}
When collapsing frames in the Flame Chart viewer in VSCode, we can quickly identify opportunities for optimizations.
This also supports multi-config environments. In that case, trace file names are created using a short representation of the configuration.
User guide for benchmarks in Fantom, including how to use this, will be done in a future diff.
NOTE: This still doesn't work in OSS because we don't support optimized mode there. In dev mode, there's a segmentation fault coming from this line: `hermesRuntime->sampledTraceToStreamInDevToolsFormat(fileStream)`
Reviewed By: sammy-SC
Differential Revision: D78905646
fbshipit-source-id: 382ddd5034db601309bd118cedde2fe0d57fde98
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53034
Changelog: [internal]
This is just a refactor to make sure that the constants we pass from the Fantom runner to its runtime are correct by using Flow to typecheck it.
Reviewed By: andrewdacenko
Differential Revision: D79565574
fbshipit-source-id: cbbab9cdec5ef5b3c82b929b8939c76c0ef41823
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52985
This class is essentially a wrapper of LayoutShadowNode with no extra logic added.
Let's remove it.
Changelog:
[Internal] [Changed] -
Reviewed By: alanleedev
Differential Revision: D79450688
fbshipit-source-id: 943e10e602cb9a5b77fca81e11d2333828b27813
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53025
It's now time to say goodbye to the Legacy Architecture :')
This change hardcodes the `newArchEnabled` property to true, and warns the users
if they're attempting to set it to false.
Changelog:
[Android] [Breaking] - Remove possibility to newArchEnabled=false in 0.82
Reviewed By: cipolleschi
Differential Revision: D78560296
fbshipit-source-id: ccfc45d2f7f21cc20e063cb901d76be3d41458d6
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53030
Changelog: [internal]
Removes `PerformanceEntryReporter::getCurrentTimeStamp` in favor of `HighResTimeStamp::now`, to make the source of truth more explicit.
Reviewed By: hoxyq
Differential Revision: D79560370
fbshipit-source-id: 0ccf2bf511781d3c47c6ddb4dd7f2061aab152b5
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53028
Changelog: [internal]
Now that we have mocking at a more fundamental level (`HighResTimeStamp` API) we can replace other timing mocks with that one.
This does it for `PerformanceEntryReporter` and the `NativePerformance` module.
Reviewed By: hoxyq
Differential Revision: D79557640
fbshipit-source-id: 86579b8bb586190ab7cc8721f30e60b3ef789798
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53018
Changelog: [internal]
This makes the test for LongTasks API use the new API for mocking timers in Fantom to make it deterministic, and re-enables it on Github.
Reviewed By: rshest
Differential Revision: D79554724
fbshipit-source-id: 984c66ecd7c20eb972ba1e6b19944532acb82246
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53019
Changelog: [internal]
This adds support for mocking `HighResTimeStamp` values in Fantom tests via a new `Fantom.installHighResTimeStampMock` function.
See new tests for more details on how it works.
Reviewed By: rshest
Differential Revision: D79554723
fbshipit-source-id: 8b0fb292948be118c7616fde1a8a84014af82de8
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53020
Changelog: [internal]
This adds a new feature to `HighResTimeStamp` to set a custom timestamp provider for "now" that can be useful for testing, only in debug builds to avoid potentially regressing performance.
Reviewed By: hoxyq, rshest
Differential Revision: D79554725
fbshipit-source-id: c325d05999b9e2d69f769b61f15c763446777a0a
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53021
Changelog: [internal]
Moving the logic to set the default value for `HighResTimeStamp` to a shared function, to simplify further changes.
Reviewed By: rshest
Differential Revision: D79554726
fbshipit-source-id: cd0d4567ef63d386d28e0325203169323e97b207
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53033
This diff replaces the logic introduced in D72078450 to prevent `onPointerEnter`/`onPointerLeave` from firing when a button is pressed. The new approach trades off some complexity for reliability: instead of deferring `ACTION_HOVER_EXIT` handling to the next frame, we now suppress it immediately if any button is pressed (`buttonState != 0`). This simpler logic appears to work reliably on Quest devices, though it may behave differently on the Android emulator (something we’ll monitor).
The main reason for this change is that deferring ACTION_HOVER_EXIT introduces problems in newer Spatial React use cases, particularly when a single component hierarchy spans multiple roots. For example, when hovering between ReactSurfaceRoot and another root like VolumetricWindow, deferring ACTION_HOVER_EXIT can lead to incorrect enter/exit ordering:
* Cursor starts hovering over `ReactSurfaceRoot`
* Cursor moves to `VolumetricWindow`
* `ACTION_HOVER_EXIT` (`ReactSurfaceRoot`) — deferred
* `ACTION_HOVER_ENTER` (`VolumetricWindow`) — processed
* `ACTION_HOVER_EXIT` (`ReactSurfaceRoot`) — processed (too late)
This results in inconsistent hover state updates across roots, which this diff resolves by handling `ACTION_HOVER_EXIT` immediately when appropriate.
Changelog: [Internal]
Reviewed By: Abbondanzo
Differential Revision: D79504775
fbshipit-source-id: ea97bff48ddf4d3d09caf56ca29057c202b12409
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53027
Tweaks MIME type parsing in CDP Network messages, now matching Chrome.
This fixes response preview behaviour by the frontend for text response previews that are `base64Encoded` 🙌🏻 (we were observing these for JSON `fetch` calls on iOS).
Changelog: [Internal]
Reviewed By: vzaidman
Differential Revision: D79559495
fbshipit-source-id: 2565af7587fc6fbdd3ef6fcbb10c558341ddfbdc
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53022
Following D77799617, D77927896, updates `InspectorNetworkReporter.kt` to check `isDebuggingEnabled` internally and avoid work/communication over the JNI layer — to minimise impact on the Android Network stack.
Changelog: [Internal]
Reviewed By: hoxyq
Differential Revision: D78004462
fbshipit-source-id: 2bea2ee0592d68d1cb330ac82e8b3b227b54a675
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53031
# Changelog:
[Internal] -
This partially reverts https://github.com/facebook/react-native/pull/52905, as in some configurations we don't appear to be able to use RN feature flags on the module level.
The usage is removed for now to unbreak the builds, with a follow up to resolve it in an adequate manner.
Reviewed By: hoxyq
Differential Revision: D79562056
fbshipit-source-id: 45bd896d572ff926a4c2dfa98334bf998718d86b
Summary:
This Diff simply adds some docs on how the secret must be formatted, and removes a print that would expose the triager IDs is anyone would look at the logs (not a big deal given that the ids are public on Discord, though).
## Changelog:
[Internal] -
Reviewed By: cortinico
Differential Revision: D79556988
fbshipit-source-id: 23d6e72141dff4e91242cc1d9f5b95ebaf5ca858
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52989
Adds a call to `NativeAnimatedModule`'s `userDrivenScrollEnded` method whenever a scroll event completes a smooth scroll animation. This is necessary in cases where Animated events control any layout properties of children and we need to force the shadow tree to resync with the native tree. For example, if a scroll view's child transforms its scale based on the scrollX or scrollY properties and the user triggers a `scrollToOffset` or `scrollToIndex` call, we don't update the layout of that child until the next state change.
Changelog: [Android][Fixed] - Fixed an issue where shadow tree and native tree layouts mismatch at the end of a scroll event
Reviewed By: sammy-SC
Differential Revision: D79464176
fbshipit-source-id: fee5f1c522714dbcddf8836de291c05d10e6e90e
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53024
This class is Legacy Arch and is not used in OSS. Let's make it internal.
Changelog:
[Internal] [Changed] -
Reviewed By: RSNara
Differential Revision: D79556615
fbshipit-source-id: d157fe8f04784038d64657c6d240b0c51e41d82d
Rubén Norte
Ruslan Shestopalyuk
Vitali Zaidman
Riccardo Cipolleschi
Ruslan Lesiutin
Nicola Corti
nishan (o^▽^o)
Peter Abbondanzo
Sam Zhou
Zeya Peng
Andrew Datsenko
Alex Hunt
Devan Buggay
Fabrizio Cucci
Mateo Guzmán
Nolan O'Brien
Samuel Susla