# V2 Multi-Platform Builds

`.github/workflows/v2-multiplatform-build.yml` defines the parallel CI matrix
for Linux, macOS, Windows, and WASM. The matrix is validated by
`V2/ue/Tools/check-v2-multiplatform-ci.py` against
`V2/ue/Build/CI/v2-multiplatform-builds.json`.

The matrix runs with `fail-fast: false` and `max-parallel: 4` so one platform
does not hide failures in another platform lane. Linux and macOS use
`UE_RUN_UAT BuildGraph` targets from `V2/ue/Build/Build.xml`; Windows runs the
Win64 shipping BuildGraph target; WASM installs `wasm32-unknown-unknown`,
`wasm32-wasip1`, and `wasm32-wasip2` before building `v7-dev-hygiene` with
`cargo build --release --locked`.

Required gates:

- `multi-platform-ci-linux`
- `multi-platform-ci-macos`
- `multi-platform-ci-windows`
- `multi-platform-ci-wasm`
- `multi-platform-ci-parallelism`

The primary parallelism metric is `build.multiplatform.parallel_jobs`. Build
evidence is uploaded as per-platform artifacts named `v2-multiplatform-linux`,
`v2-multiplatform-macos`, `v2-multiplatform-windows`, and
`v2-multiplatform-wasm`.

The CI validator is:

```bash
python3 V2/ue/Tools/check-v2-multiplatform-ci.py
```