Summary:
Pull Request resolved: https://github.com/react/react-native/pull/58605
Use global DOM APIs, supported React Native entry points, and package-relative implementation imports throughout Fantom. Use the renderer-only private interface for the existing public-instance conversion helpers instead of importing Node internals.
Changelog: [Internal]
Reviewed By: cipolleschi
Differential Revision: D120717572
fbshipit-source-id: 1aae11b7b9434c783d42ca289e2c6edd17aa887c
Summary:
Pull Request resolved: https://github.com/react/react-native/pull/57783
# Changelog: [Internal]
Adds the `enableConditionalUseWarning` dynamic React feature flag, which the React renderer reads from `ReactNativeInternalFeatureFlags`. The flag gates the new warning for conditional use of `use()` based on cache state: https://react.dev/warnings/conditional-use-of-use
This is a dev-only warning, I don't see any reasons to control this via gk.
Reviewed By: antonk52
Differential Revision: D114407789
fbshipit-source-id: d63dd09180e6560a82d178610c7ae24b9e31b65e
Summary:
Pull Request resolved: https://github.com/react/react-native/pull/57587
Adds rethrow in catch blocks when `startJSSamplingProfiler()` fails, preventing the `finally` block from attempting to stop a profiler that was never started.
Changelog: [Internal]
Reviewed By: thegreatercurve
Differential Revision: D112405579
fbshipit-source-id: 4b1cc6746d8ba29df99be57e583ee06ac742c12c
Summary:
Pull Request resolved: https://github.com/react/react-native/pull/57387
Adds `yarn fantom-cli`, an interactive REPL that evaluates JavaScript against the same native tester binary and Hermes runtime that Fantom tests run in. State persists across lines, input goes through Metro/Babel (so `import`, JSX and Flow all work), and the environment is set up the same way tests set it up — `React`, `ReactNative` and the `Fantom` API are available globally, so you can render surfaces and drive them interactively from the prompt.
The native tester gains an `--interactive` mode that loads a warm-up bundle without running tests and then evaluates length-prefixed snippets read from stdin, reporting results, console output and errors back as newline-delimited JSON. A Node driver hosts a Metro server, builds the warm-up bundle, spawns the binary, and bridges each line of input into the live runtime (top-level declarations persist across evaluations).
Features:
- Console-style output: results are printed with an inspector similar to the Chrome DevTools / Node.js consoles (nested objects/arrays up to a depth limit, quoted strings, functions/classes, `Map`/`Set`/`RegExp`/`Date`/`Error`, class instances, circular references, multi-line wrapping), colorized by type when stdout is a terminal. Inspecting a property never aborts the result or leaks into later evaluations: a property whose getter fails renders as `[Thrown: <error>]`, including getters that fail asynchronously through the runtime's global error handler (e.g. accessing a `react-native` export backed by a TurboModule that isn't registered).
- Autocompletion: pressing Tab completes global identifiers, in-scope bindings and object properties (property names are listed without invoking getters).
- Node-like CLI: with no arguments it starts the REPL; `-e <code>` evaluates a snippet and exits; a filename runs that script and exits. In the non-interactive modes the value of a trailing expression is not printed (use `console.log`) and a thrown error exits with a non-zero status code.
Also documents the REPL in the Fantom README.
Changelog: [Internal]
Reviewed By: javache, sammy-SC
Differential Revision: D110187712
fbshipit-source-id: 3e76c498ae04b8b1ce9e0e27e5ce6b6a0cd11e09
Summary:
Pull Request resolved: https://github.com/react/react-native/pull/57358
The `enableEagerAlternateStateNodeCleanup` flag is no longer read by the renderer, so the feature-flag definition and the two prelude overrides that forced it on become dead code.
[Internal]
Reviewed By: lenaic
Differential Revision: D110043719
fbshipit-source-id: 24a7e2b85ec60da1cb1855f444bba5e1e6fc4288
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55892
Adds `toMatchInlineSnapshot()` to the Fantom custom `expect` implementation,
matching Jest's inline snapshot behavior. On first run, snapshot values are
written directly into the test source file as template literal arguments.
On subsequent runs, values are compared and the test fails on mismatch
unless the `-u` flag is passed to force an update.
The implementation spans the two-process Fantom architecture:
**Runtime (Hermes VM):**
- `snapshotContext.js`: New `toMatchInlineSnapshot` method that compares
received values against existing inline snapshots, captures stack traces
for new/mismatched snapshots, and tracks results per test.
- `expect.js`: New `toMatchInlineSnapshot` method on the `Expect` class
that serializes values with `prettyFormat` and delegates to snapshot context.
- `setup.js`: Plumbs `inlineSnapshotResults` through `TestCaseResult`.
**Runner (Node.js):**
- `snapshotUtils.js`: New `processInlineSnapshotResults` resolves VM stack
traces back to original source locations via source map symbolication.
New `saveInlineSnapshotsToSource` directly rewrites the test source file
by finding each `toMatchInlineSnapshot(...)` call and replacing its
argument with the formatted template literal. This avoids jest-snapshot's
`saveInlineSnapshots` which requires Babel and Prettier 2.x.
- `runner.js`: Generates source maps when inline snapshots need updating,
collects pending snapshots across test configs, and writes them after
all configs complete.
Changelog: [Internal]
Reviewed By: sammy-SC
Differential Revision: D95077617
fbshipit-source-id: 6a25c8ce966ed71ecd8977c13c25de5907311c6e
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55860
Changelog: [Internal]
This diff adds the ability to convert LLVM coverage JSON output to LCOV format for C++ code coverage in react-native-fantom.
Key additions:
- `convertLLVMCoverage.js`: Converts LLVM coverage data (segments, branches, functions) to LCOV format lines
- `types.flow.js`: Flow type definitions for LLVM coverage data structures
- Test utilities and fixtures for validating the conversion with real coverage data from various C++ files (AppSettings.cpp, Class.h, DevSettingsModule.h, NativeFantom.cpp/h, RawPropsKey.cpp)
This enables reporting C++ code coverage from Fantom tests in a standard format that can be consumed by coverage tools.
Reviewed By: sammy-SC
Differential Revision: D90135000
fbshipit-source-id: 3b22250c4b1665748b6ccb4feb79cc1c20ec7fa6
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55614
- enableFragmentRefsInstanceHandles
- Enables a pointer on each element back to the FragmentInstances that control it. Needed to implement the common IntersectionObserver pattern of reusing IntersectionObservers across multiple callbacks. See more in https://github.com/facebook/react/pull/34935
- enableFragmentRefsTextNodes
- This should be a noop on RN as unlike dom, text nodes are considered host components and already handled. Text without a `<Text/>` wrapper throws an error.
Changelog: [Internal]
Reviewed By: christophpurrer
Differential Revision: D93479122
fbshipit-source-id: 639369893c8aafc1d2bf0ffbdf4bf09fe6dca45c
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53410
Changelog: [Internal]
Adding babel-istanbul-plugin to instrument bundle code with coverage reporting.
Metro will transform source code only when coverage flag is set up globally in jest.
Coverage map is then provided by runner as part of test result.
Reviewed By: sammy-SC
Differential Revision: D80716433
fbshipit-source-id: 3831f227f8793f874f0d2366759bb6916e747c72
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53143
# Changelog:
[Internal] -
This refactors the way Fantom benchmark test results are passed to the top level, making it type safe and more maintainable.
Reviewed By: andrewdacenko
Differential Revision: D79812707
fbshipit-source-id: d8bfef7e1b0c11b277a08f5e4c810f8c1efd7f89
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/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/52765
Changelog: [internal]
Reported locations for errors in Fantom is wrong, because it seems it's not ignoring "infra" frames.
This was caused by the `stack` property in `ErrorWithCustomBlame` being set on the error objects and shadowing the getter that removes the necessary frames. This fixes that by forcing that property to be deleted.
Reviewed By: christophpurrer
Differential Revision: D78747119
fbshipit-source-id: 81d6ce74041382d7582e2066409e839d28d91052
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52601
Changelog: [internal]
Fixes a bug in Fantom when throwing a value that's not an instance of `Error` in a test.
Reviewed By: javache
Differential Revision: D78332756
fbshipit-source-id: 350479dcb7bcea399070c6851aca76a1d1cc2629
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52474
1. Enables the feature flags for fragment refs on fbsource
2. Adds a test with Fantom for usage of `FragmentInstance#observeUsing` and `FragmentInstance#unobserveUsing`.
3. Exposes the `ReactFragmentInstance` type with the common methods that are used on native. We can override the DOM only methods in www libdefs.
Changelog: [Internal]
Reviewed By: rubennorte
Differential Revision: D74326262
fbshipit-source-id: e35ee45b23179ad3ba5527763567c9b04c127eff
Rubén Norte