`yarn react-native upgrade` uses npm, not yarn

[IanVS]

Environment

 React Native Environment Info:
 System:
 OS: macOS 10.15.2
 CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
 Memory: 4.69 GB / 32.00 GB
 Shell: 5.7.1 - /bin/zsh
 Binaries:
 Node: 12.14.1 - /var/folders/8v/nt6q98150ss138rdc78htqxr0000gn/T/yarn--1580150374542-0.30379921037702373/node
 Yarn: 1.18.0 - /var/folders/8v/nt6q98150ss138rdc78htqxr0000gn/T/yarn--1580150374542-0.30379921037702373/yarn
 npm: 6.13.2 - ~/.nvm/versions/node/v12.14.1/bin/npm
 SDKs:
 iOS SDK:
 Platforms: iOS 13.2, DriverKit 19.0, macOS 10.15, tvOS 13.2, watchOS 6.1
 IDEs:
 Android Studio: 3.5 AI-191.8026.42.35.6010548
 Xcode: 11.3.1/11C504 - /usr/bin/xcodebuild
 npmPackages:
 react: 16.8.3 => 16.8.3
 react-native: 0.59.9 => 0.59.9

Description

I'm trying to upgrade react-native, and having some problems. I'm not sure if it's the root cause or not, but I notice that npm is being used to install my dependencies, even though I'm in a yarn workspace environment. I see that there's a preferYarn option in the PackageManager (

cli/packages/cli/src/tools/packageManager.ts

Line 49 in 935ad66

if (options && options.preferYarn !== undefined) {

), but this doesn't seem to actually be used anywhere in the upgrade code. Is this intentional?

[thymikee]

Do you have yarn.lock present in your project? If the preferYarn options is not passed to package manager (like in this case, because we should be able to infer it), this is used:

cli/packages/cli/src/tools/yarn.ts

Lines 45 to 47 in 6ce799f

	export function isProjectUsingYarn(cwd: string) {
	return findUp.sync('yarn.lock', {cwd});
	}

Can you hook into this code and see what's happening?

[IanVS]

I do have a yarn.lock, but as I mentioned, I'm using yarn workspaces, so the lockfile lives at my project root, but my mobile code is in projRoot/client/mobile, and that is where isProjectUsingYarn is looking for a lock file. It doesn't find it (because it's actually two directories up), so it uses npm instead.

Edit: I just noticed that your snippet looks different from what's in my node_modules. I'm using version 2.10, which is what is compatible with the version of react-native I'm using. It looks like:

cli/packages/cli/src/tools/yarn.js

Lines 51 to 53 in ca9947d

	export function isProjectUsingYarn(projectDir) {
	return fs.existsSync(path.join(projectDir, 'yarn.lock'));
	}

which doesn't seem to search upwards. Perhaps the fix in the more recent versions could be backported to the older branches? After all, it's difficult to upgrade to newer versions that have the fix if the upgrade tool is broken. ;)

[IanVS]

It looks like this was probably fixed by #768 for 3.x and above. So once I get on RN 0.61 I should be fine. It would be nice to have this fix in older versions, but I'm guessing that's not really easy to backport, so I'll close out the issue.

[thymikee]

Awesome, thanks for the followup :)