React Native fix for libraries failing with ReactCommon/RCTHost.h not found - CNG - Config Plugin - Podfile fix

fix-react-native-rcthost-not-found.md

What

If you’re using Zeego or any other React Native library that throws weird framework-related errors like “ReactCommon/RCTHost.h not found”, this is for you. The issue started with RN 0.78+ and usually only affects the old architecture with useFrameworks: 'static'.

Versions before 0.78, setups without useFrameworks, or users on the new architecture are not affected, thus do not need this workaround.

Fix for Expo users

I’ve prepared a config plugin for you. Create a file, e.g. plugins/with-runtime-framework-headers.js, with the following contents:

const { withPodfile } = require('expo/config-plugins')

const PATCH_START = '## >>> runtime-framework headers'
const PATCH_END = '## <<< runtime-framework headers'

const EXTRA_HDRS = [
  '${PODS_CONFIGURATION_BUILD_DIR}/React-RuntimeApple/React_RuntimeApple.framework/Headers',
  '${PODS_CONFIGURATION_BUILD_DIR}/React-RuntimeCore/React_RuntimeCore.framework/Headers',
  '${PODS_CONFIGURATION_BUILD_DIR}/React-jserrorhandler/React_jserrorhandler.framework/Headers',
  '${PODS_CONFIGURATION_BUILD_DIR}/React-jsinspector/jsinspector_modern.framework/Headers',
  '${PODS_CONFIGURATION_BUILD_DIR}/React-runtimescheduler/React_runtimescheduler.framework/Headers',
  '${PODS_CONFIGURATION_BUILD_DIR}/React-performancetimeline/React_performancetimeline.framework/Headers',
  '${PODS_CONFIGURATION_BUILD_DIR}/React-rendererconsistency/React_rendererconsistency.framework/Headers',
]

function buildPatch() {
  return [
    PATCH_START,
    '  extra_hdrs = [',
    ...EXTRA_HDRS.map((h) => `    "${h}",`),
    '  ]',
    '',
    '  installer.pods_project.targets.each do |t|',
    '    t.build_configurations.each do |cfg|',
    "      cfg.build_settings['HEADER_SEARCH_PATHS'] ||= '$(inherited)'",
    "      cfg.build_settings['HEADER_SEARCH_PATHS']  << \" #{extra_hdrs.join(' ')}\"",
    '    end',
    '  end',
    PATCH_END,
  ].join('\n')
}

module.exports = function withRuntimeFrameworkHeaders(config) {
  return withPodfile(config, (config) => {
    let podfile = config.modResults.contents

    // 1️⃣ ensure there's a post_install block
    if (!/^\s*post_install\s+do\s+\|installer\|/m.test(podfile)) {
      podfile += `

post_install do |installer|
end
`
    }

    const patch = buildPatch()

    if (podfile.includes(PATCH_START)) {
      // 🔄 update existing patch
      podfile = podfile.replace(new RegExp(`${PATCH_START}[\\s\\S]*?${PATCH_END}`), patch)
    } else {
      // ➕ insert right after the post_install opening line
      podfile = podfile.replace(
        /^\s*post_install\s+do\s+\|installer\|.*$/m,
        (match) => `${match}\n\n${patch}`
      )
    }

    console.log('✅  with-runtime-framework-headers: Podfile updated')
    config.modResults.contents = podfile
    return config
  })
}

Open your app.config.ts/js/json and add './plugins/with-runtime-framework-headers.js' to your Expo plugins section. Trigger npx expo prebuild --clean and you should be done!

Fix for bare React Native users without CNG (💔)

If you’re a bare React Native user, the fix is pretty simple. Open your ios/Podfile and insert the following lines in the post_install segment, right after react_native_post_install().

Make sure to run npx pod-install --repo-update afterwards.

    extra_hdrs = [
      "${PODS_CONFIGURATION_BUILD_DIR}/React-RuntimeApple/React_RuntimeApple.framework/Headers",
      "${PODS_CONFIGURATION_BUILD_DIR}/React-RuntimeCore/React_RuntimeCore.framework/Headers",
      "${PODS_CONFIGURATION_BUILD_DIR}/React-jserrorhandler/React_jserrorhandler.framework/Headers",
      "${PODS_CONFIGURATION_BUILD_DIR}/React-jsinspector/jsinspector_modern.framework/Headers",
      "${PODS_CONFIGURATION_BUILD_DIR}/React-runtimescheduler/React_runtimescheduler.framework/Headers",
      "${PODS_CONFIGURATION_BUILD_DIR}/React-performancetimeline/React_performancetimeline.framework/Headers",
      "${PODS_CONFIGURATION_BUILD_DIR}/React-rendererconsistency/React_rendererconsistency.framework/Headers",
    ]

    installer.pods_project.targets.each do |t|
      t.build_configurations.each do |cfg|
        cfg.build_settings['HEADER_SEARCH_PATHS'] ||= '$(inherited)'
        cfg.build_settings['HEADER_SEARCH_PATHS']  << " #{extra_hdrs.join(' ')}"
      end
    end