Improving expo upgrade in a monorepo

[nandorojo]

expo upgrade doesn't work well in monorepos, since it only upgrades packages in the app folder, so there are tons of mismatches across the repo. It also doesn't detect lingering incorrect versions of transitive dependencies, such as babel-preset-expo's version as a dependency of @expo/next-adapter.

I think it would be good for expo upgrade to run yarn why for every package it wants to upgrade, starting at the root of a monorepo (if it's in one), and indicate any packages that have the wrong versions based on the result of yarn why.

Expected Behavior

I would expect the following behavior of expo upgrade in a monorepo:

1. In apps/expo, run expo upgrade
2. Detect if in a workspace
3. If in a workspace, traverse all apps or packages, as defined by workspaces in root package.json
4. Detect all Expo apps
5. Open a prompt asking which Expo apps should get upgraded, if there are more than one. For example, if you have apps/expo, and apps/expo-admin, maybe you could upgrade both.
6. Next, for all packages defined by workspaces in root package.json, upgrade the Expo dependencies as intended (ideally using fixed versions rather than range versions.)
7. Run yarn why for every package we want to upgrade. Also run it for nested dependencies to make sure we have the right versions. By nested dependency, I mean things like babel-preset-expo, expo-dev-menu, etc.

• Currently, I believe expo upgrade is detecting versions of packages based on what they are inside of package.json.
• This is problematic, because libraries like babel-preset-expo are dependencies of both an expo app, but also of @expo/next-adapter, and thus the versions will often mismatch (see Upgrade babel-preset-expo #4377).

Methodology

By using yarn why, we can detect the following:

1. Are we using the desired version of an expo package
2. (Perhaps more importantly) do we have multiple, mis-matching versions of an expo package

• This is a common cause of dependency hell in a monorepo. Since expo upgrade is running such a massive set of upgrades in one swoop, it can be very hard to debug the root of these dependency issues manually. A script that does it for you would be a big upgrade.

This package turns yarn why into JSON: https://gitlab.com/leipert-projects/yarn-why-json#readme

Reproduction

1. npx create-solito-app@latest solito-app
2. cd solito-app/apps/expo
3. expo upgrade
4. cd ../..
5. yarn install
6. Try to build the expo app / next site