Commit Graph

9 Commits

Author SHA1 Message Date
Ruslan Shestopalyuk e3183739bb Options to run Fantom with address and thread sanitizers enabled (#53300)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53300

# Changelog:
[Internal] -

This adds two new modes to Fantom, allowing to run the native (C++) side with enabling either:
* Address sanitizer, which would detect memory overwrites
* Thread sanitizer, which can detect potential threading issues, such  as race conditions

This are opt-in for now.

Currently, both modes already detect different errors, which have a high chance to be real issues and have to be fixed.

Reviewed By: lenaic

Differential Revision: D80339524

fbshipit-source-id: 784ddb9f0af79a04b074e107e4955724d54d5685
2025-08-15 08:12:04 -07:00
Rubén Norte 65974e938c Add support for JS debugging in Fantom (#53215)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53215

Changelog: [internal]

This adds a new environment variable to Fantom that allows debugging the JS code in tests.

Usage:

```
FANTOM_DEBUG_JS=1 yarn fantom <test>
```

**Does NOT work in OSS yet**. We need to include a third-party library to send HTTP and WebSocket requests and implement a wrapper on top of it.

Reviewed By: christophpurrer

Differential Revision: D79883372

fbshipit-source-id: d077c373a036033344e61d58274d5cd14028bda4
2025-08-12 05:41:11 -07:00
Rubén Norte 789fc57254 Improve API to take JS heap snapshots in Fantom (#53071)
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
2025-08-06 05:40:02 -07:00
Rubén Norte b903ed7940 Add support for JS sampling profiler (#52827)
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
2025-08-05 05:36:26 -07:00
Rubén Norte 54d733311d Add validation for environment variables for Fantom (#52779)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52779

Changelog: [internal]

Adds validation for Fantom environment variables at runtime, to catch typos or variables that no longer have an effect.

Reviewed By: rshest

Differential Revision: D78803045

fbshipit-source-id: efb28a4f3fd6a4be35fb525d91fb093a1e88f7e4
2025-07-23 04:41:42 -07:00
Rubén Norte 130b46c117 Add new environment variables to force CI and debug C++ (#52776)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52776

Changelog: [internal]

`FANTOM_FORCE_CI_MODE` is just an explicit way to indicate that we're on CI, so we'd run benchmarks in test mode, for example.

`FANTOM_DEBUG_CPP` is just an alias for `FANTOM_ENABLE_CPP_DEBUGGING` which is unnecessarily long.

Reviewed By: rshest

Differential Revision: D78801918

fbshipit-source-id: 8e60bdd911067c6b0b92be7e90553fd5209c9ca9
2025-07-23 04:41:42 -07:00
Rubén Norte 342b88d0d3 Create new environment variable to force running benchmarks in test mode (#52759)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52759

Changelog: [internal]

This introduces a new environment variable for Fantom to disable benchmarks (`FANTOM_FORCE_TEST_MODE`), without having to run in CI mode.

Reviewed By: rshest

Differential Revision: D78672864

fbshipit-source-id: ef445bd8b36703594658529da2436c75d5b87179
2025-07-23 04:41:42 -07:00
Andrew Datsenko d0770ce425 Introduce isOSS (#52222)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52222

Changelog: [Internal]
Introduce environment option to force usage of OSS fantom test runner.
If env is not set - check for BUCK file in tester which is checked in for FB but not for OSS.

Reviewed By: rubennorte

Differential Revision: D77160761

fbshipit-source-id: 1701ff140ff2be1bbeacfb4305e9f89089cacb42
2025-06-26 11:03:20 -07:00
Tim Yung d6f29c8afd RN: Move {packages => private}/react-native-fantom (#51938)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/51938

Moves `packages/react-native-fantom` to `private/react-native-fantom`.

Changelog:
[Internal]

Reviewed By: huntie

Differential Revision: D76368959

fbshipit-source-id: 8d62f792229c10cd108dc849e8629d3174dc72c1
2025-06-11 23:49:51 -07:00