4 people 3255b89c34 feat(transform-react): add reportDiagnostics option to expose recoverable React Compiler diagnostics (#26624) ...

## What

Adds an opt-in `reactCompiler.reportDiagnostics` option to
`oxc-transform-react`. When `true`, the recoverable diagnostics the
React Compiler produced for a successful compile
(`CompileResult::Success { diagnostics }`) are appended to
`result.errors` alongside code, keeping the category severity the
compiler assigned (`Error` for `Suppression`, `Warning` for
`IncompatibleLibrary`, ...). `fatal` keeps its meaning and tells whether
`code` is usable.

The default is unchanged: recoverable diagnostics stay omitted, matching
Babel's default `logger: null` as decided in #26128.

## Why

Since #26128 (0.148.0) there is no way to learn *why* a function was
skipped: `errors` is fatal-only, and `panicThreshold` is not a
substitute because it aborts at the first diagnostic without producing
code. Consumers that need the reasons — a burndown inventory when
adopting the compiler, or checking which `eslint-disable` suppressions
actually took effect — lost their only channel. Details and a repro are
in #26318.

Two concrete downstream effects on 0.148+:

- `@vitejs/plugin-react` added `logDiagnostics`
(vitejs/vite-plugin-react#1431) one day after #26128, reading
recoverable diagnostics from `result.errors`; with the current binding
that option is a no-op. With this PR it only needs to forward
`reportDiagnostics: logDiagnostics`.
- `outputMode: 'lint'` / `noEmit` return `errors: []`, so lint mode has
no observable output at the Node boundary.

Babel's `logger` is the knob that turns these reports on; this option is
the non-callback equivalent. Upstream's own native bridge
(`babel-plugin-react-compiler-rust`) likewise returns every event on the
native result and lets the JS shim apply `logger: null`.

## Design notes

- **Opt-in rather than a new always-populated field**, so the default
result is byte-identical to today and nobody pays for rendering
codeframes they never read.
- **Reuses `errors`** instead of adding a second array: `errors` already
carries non-fatal parser and transformer warnings, and the 0.147 shape
(recoverable compiler diagnostics in `errors`, `fatal` to tell if output
is usable) is what existing consumers were written against.
- The severities are forwarded as the compiler assigned them (no `Error
→ Warning` rewrite as in 0.147); `fatal` is the fatality signal, as
documented on `oxc_react_compiler::compile`.

## Verification

- `napi/transform-react`: `pnpm run build-dev && pnpm test` — 33 tests
pass (3 new: opt-in vs default, multiple diagnostics with their own
severities, lint mode).
- `cargo fmt --check`, `cargo clippy -p oxc_transform_react_napi
--all-targets --all-features -- -D warnings`, `typos` on the touched
files.
- Repro from #26318 against this build (`memoized` = `_c(` count, shows
the suppression is still honored):

```
                    default        reportDiagnostics: true
default          errors: 0      errors: 1 (Suppression, label = the eslint comment)
no suppressions  errors: 0      errors: 0, memoized: 2
lint             errors: 0      errors: 1, memoized: 0
panic            fatal, 1       unchanged
```

- Ran the real consumer from #26318 (a suppression gate that maps
`react-compiler(Suppression)` labels back to the component they cover)
against this build: with the option it recovers all 5 expected sites
across the codebase; against published 0.149.0 it finds none.

`index.d.ts` is regenerated by `napi build`;
`transform-react.wasi.d.cts` mirrors it by hand, as in #26128.

closes #26318

---

AI usage disclosure (per AGENTS.md): this PR was drafted with Claude
Fable 5.1. I reviewed the diff; the verification steps above were run on
my machine against this branch.

---------

Co-authored-by: JacktheRanger <219502738+JacktheRanger@users.noreply.github.com>
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
Co-authored-by: Cameron Clark <cameron.clark@hey.com>

2026-09-25 11:58:39 +01:00

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transform.test.ts

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