[metro-config] pass in custom serializer to expo default config

[quinlanj]

Why

I want my metro.configs.js to use the sentry custom serializer. It will look something like this:

const {
  getDefaultConfig,
} = require("/Users/quin/Documents/expo/packages/@expo/metro-config/build/ExpoMetroConfig");
const {
  createChunkSerializer,
} = require("/Users/quin/Documents/expo/packages/@expo/metro-config/build/serializer/serializeChunks");
const { mergeConfig } = require("metro");
const {
  createSentryMetroSerializer,
} = require("@sentry/react-native/dist/js/tools/sentryMetroSerializer");

const config = getDefaultConfig(__dirname, {
  customSerializer: createSentryMetroSerializer(createChunkSerializer()),
});

module.exports = config;

How you can help

I noticed that the passed in serializer is only called when the output is not static. However, I want this seriaIizer to be called in the static case. I noticed we split the modules up into chunks and then serialize the chunks . When we serialize each chunk to code, I'm thinking we can use the passed in serializer there. Any guidance someone can give me would be much appreciated!

Test Plan

Ran expo-dev export --output-dir dist --dump-sourcemap on my test app to verify that it works

Checklist

• Documentation is up to date to reflect these changes (eg: https://docs.expo.dev and README.md).
• Conforms with the Documentation Writing Style Guide
• This diff will work correctly for npx expo prebuild & EAS Build (eg: updated a module plugin).

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⚠️ Suggestion: Missing changelog entries

Your changes should be noted in the changelog. Read Updating Changelogs guide and consider adding an appropriate entry to the following changelogs:

• packages/@expo/metro-config/CHANGELOG.md

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[krystofwoldrich]

@quinlanj This looks great!

This will work for JSC iOS/Android and I assume also Web.

But for Hermes, the Debug ID gets lost when composing the Hermes source map.

What is the easiest way to try the changes from this branch? I've seen you mentioned expo-dev, but I don't know how it works.

[quinlanj]

@krystofwoldrich

On trying the changes on the branch: When I run expo-dev, i'm running the cli from source that maps to /my/path/expo/packages/@expo/cli/build/bin/cli. But I suspect it will also work if you ran just expo export and have your metro.config.js reference the path of the development source code. For example:

const {
  getDefaultConfig,
} = require("/Users/quin/Documents/expo/packages/@expo/metro-config/build/ExpoMetroConfig");

On Hermes Debug ID - You'll need to add this bit back to write the packager source map to disk, but iirc, if I run your copy-debug-id script it should move the debug id to the composed hermes source map

[quinlanj]

closing in favour of #25859