DO NOT MERGE: native iOS coverage setup (local harness fork)

[mfazekas]

Do not merge — this PR contains local file: and portal: references to the react-native-harness fork.

What this does

Sets up native iOS code coverage collection using @react-native-harness/coverage-ios from the mfazekas/react-native-harness fork (feat/native-ios-coverage branch).

How to use

Prerequisites: clone the harness fork at /Users/boga/Work/Margelo/react-native-harness and check out feat/native-ios-coverage.

1. Fix harness fork (one-time setup)

The packages/cli package is used as the portal target for react-native-harness, but it's missing three things that Jest/Metro/npx need. Apply these fixes in the harness fork:

a) Add jest-preset.cjs — Jest requires react-native-harness/jest-preset at the package root:

cat > packages/cli/jest-preset.cjs << 'SHIM'
module.exports = {
    runner: '@react-native-harness/jest',
};
SHIM

b) Add metro.cjs — Metro config imports react-native-harness/metro. Uses realpathSync to handle --preserve-symlinks:

cat > packages/cli/metro.cjs << 'SHIM'
const path = require('path');
const fs = require('fs');
const realDir = path.dirname(fs.realpathSync(__filename));
module.exports = require(path.join(realDir, '..', 'metro', 'dist', 'index.js'));
SHIM

c) Add bin.cjs — Without a bin entry, npx downloads a fresh copy from npm instead of using the local portal:

cat > packages/cli/bin.cjs << 'SHIM'
#!/usr/bin/env node
import('./dist/index.js');
SHIM
chmod +x packages/cli/bin.cjs

d) Update packages/cli/package.json — add the exports and bin fields:

{
  "bin": {
    "react-native-harness": "./bin.cjs",
    "harness": "./bin.cjs"
  },
  "exports": {
    ...existing exports...,
    "./jest-preset": "./jest-preset.cjs",
    "./metro": "./metro.cjs"
  }
}

e) Fix packages/coverage-ios/package.json — add missing fields that cause pod validation errors:

{
  "homepage": "https://github.com/callstackincubator/react-native-harness",
  "author": "React Native Harness contributors"
}

2. Build and run coverage

yarn install
cd example/ios && pod install  # should print [HarnessCoverage] Instrumenting pods
cd ..

# Build with Xcode 16.4 (not Xcode 26 beta)
DEVELOPER_DIR=/Applications/Xcode16.4.app/Contents/Developer xcodebuild build \
  -workspace ios/RiveExample.xcworkspace -scheme RiveExample \
  -sdk iphonesimulator -destination "platform=iOS Simulator,name=iPhone 16 Pro,OS=18.6" \
  -derivedDataPath ios/build

# Install on the correct simulator
xcrun simctl install "iPhone 16 Pro" ios/build/Build/Products/Debug-iphonesimulator/RiveExample.app

# Run tests with coverage
NODE_OPTIONS="--preserve-symlinks" npx react-native-harness --harnessRunner ios --coverage

3. Collect native coverage

The debug dylib path depends on where the app is installed. Find it with:

APP_PATH=$(xcrun simctl get_app_container "iPhone 16 Pro" rive.example)

Then merge and export:

xcrun llvm-profdata merge -sparse /tmp/harness-coverage/*.profraw -o coverage/native-ios.profdata
xcrun llvm-cov export --format=lcov \
  --instr-profile=coverage/native-ios.profdata \
  "$APP_PATH/RiveExample.debug.dylib" \
  > coverage/native-ios.lcov

# HTML report
genhtml coverage/native-ios.lcov -o coverage/native-ios-html \
  --ignore-errors inconsistent,corrupt,unsupported
open coverage/native-ios-html/index.html

Why these fixes are needed

The portal resolution "react-native-harness": "portal:.../packages/cli" maps the package to the CLI sub-package, but Jest expects react-native-harness/jest-preset, Metro expects react-native-harness/metro, and npx needs a bin entry — none of which exist in the CLI package. The correct package (packages/react-native-harness) can't be used as a portal target because yarn refuses to write into a different monorepo root. These shims bridge the gap.

Known issue

The resolve-coverage-pods.mjs script needs NODE_OPTIONS="--preserve-symlinks" when using portal resolutions. After yarn install, manually patch node_modules/@react-native-harness/coverage-ios/scripts/harness_coverage_hook.rb line 19 to add this. This will be fixed upstream.