deps: Upgrade jest-expo to 42.1.0, the latest.

[chrisbobbe]

This is a bump of two major versions. Nothing seems to go wrong (and if it did, I'd expect it to only affect Jest tests, and those still all pass). But in addition to removing a hack described in the commit message, this will let us iron out any wrinkles from those major version bumps soon, so we don't have to deal with them at the time of upgrading to a potential newer version that has explicit RN v0.64 support, with something like expo/expo#13549, for #4426.

[chrisbobbe]

Also, this bit of output from git log --stat is kind of nice:

 yarn.lock    | Bin 549096 -> 512179 bytes

[gnprice]

LGTM, thanks!

There's a rebase conflict in yarn.lock, and I'm getting puzzling results when I try to resolve it.

• First, I tried using yarn's feature for this: on hitting the conflict, ran yarn, then continued the rebase.
• Then, I tried the direct approach: take just the package.json change atop current master, and run yarn from there.

With either of those, I found that yarn.lock ended up with two versions of @expo/config-plugins: a 2.0.4, and a 3.0.7. Your PR branch has only a 3.0.7. (Before the branch, it's two versions 1.0.33 and 3.0.6.)

Having just one config sounds like a good thing. Here's from yarn why @expo/config-plugins:

=> Found "@expo/config-plugins@3.0.6"
info Has been hoisted to "@expo/config-plugins"
info Reasons this module exists
   - Hoisted from "expo-apple-authentication#@expo#config-plugins"
   - Hoisted from "expo-screen-orientation#@expo#config-plugins"
   - Hoisted from "react-native-unimodules#expo-file-system#@expo#config-plugins"

=> Found "@expo/config#@expo/config-plugins@3.0.7"
info This module exists because "jest-expo#@expo#config" depends on it.

=> Found "expo-constants#@expo/config-plugins@2.0.4"
info Reasons this module exists
   - "react-native-unimodules#expo-constants#@expo#config" depends on it
   - Hoisted from "react-native-unimodules#expo-constants#@expo#config#@expo#config-plugins"

(Hmm, so I guess it's actually three versions, though 3.0.6 vs 3.0.7 is probably fine.)

Would you try to reproduce whatever you did to get the yarn.lock changes you got here the first time? 🙂

[chrisbobbe]

I'm away from my computer right now, but from that output it looks like our recent upgrade of react-native-unimodules might be a factor.

[chrisbobbe]

I'm away from my computer right now, but from that output it looks like our recent upgrade of react-native-unimodules might be a factor.

Hmm OK and react-native-unimodules looks like it was deprecated 2 hours ago; they're saying we should use expo-modules-core instead: https://github.com/expo/expo/tree/master/packages/react-native-unimodules.

Hoping to get more clarification here: expo/expo#14048 (comment) 🙂

[chrisbobbe]

Hoping to get more clarification here: expo/expo#14048 (comment) 🙂

Hmm, and it looks like that migration is still in progress on Expo's end.

@gnprice, in your comment here—

Having just one config sounds like a good thing.

—was there something specific you were concerned about (like an error) or do you think it might be OK to go ahead with this PR without doing anything special with react-native-unimodules or expo-modules-core?

[chrisbobbe]

Just rebased. Now there's just two (after running yarn yarn-deduplicate && yarn):

$ yarn why @expo/config-plugins
yarn why v1.22.10
[1/4] 🤔  Why do we have the module "@expo/config-plugins"...?
[2/4] 🚚  Initialising dependency graph...
[3/4] 🔍  Finding dependency...
[4/4] 🚡  Calculating file sizes...
=> Found "@expo/config-plugins@3.1.0"
info Has been hoisted to "@expo/config-plugins"
info Reasons this module exists
   - Hoisted from "expo-apple-authentication#@expo#config-plugins"
   - Hoisted from "expo-screen-orientation#@expo#config-plugins"
   - Hoisted from "jest-expo#@expo#config#@expo#config-plugins"
   - Hoisted from "react-native-unimodules#expo-file-system#@expo#config-plugins"
info Disk size without dependencies: "2.45MB"
info Disk size with unique dependencies: "4.49MB"
info Disk size with transitive dependencies: "7.98MB"
info Number of shared dependencies: 52
=> Found "expo-constants#@expo/config-plugins@2.0.4"
info Reasons this module exists
   - "react-native-unimodules#expo-constants#@expo#config" depends on it
   - Hoisted from "react-native-unimodules#expo-constants#@expo#config#@expo#config-plugins"
info Disk size without dependencies: "1.38MB"
info Disk size with unique dependencies: "3.27MB"
info Disk size with transitive dependencies: "6.81MB"
info Number of shared dependencies: 51
✨  Done in 0.77s.

Still, you may still be concerned about that difference in major versions.

[gnprice]

Well, I'm not entirely sure what @expo/config-plugins does. It sounds like it's providing configuration of some kind -- and if different parts of our dependency tree are working from configurations that don't agree, that seems like a recipe for bugs.

Reading that package's docs -- https://docs.expo.dev/guides/config-plugins/ , following the link at https://www.npmjs.com/package/@expo/config-plugins -- I think it's OK, though. This isn't so much providing configuration of Expo (or of its "plugins"?); rather it's providing some generic building blocks for writing bits of code ("config plugins") that in turn do things to the Expo config. IOW this package is just providing some code to do a job, and the "config" in its name is just because that job happens to relate to manipulating the Expo config.

It'd still be nice for all the different parts of our dependency tree to be using an up-to-date version, but no more so than for any other dependency.

I'll rebase and merge.

[chrisbobbe]

Thanks for the review!