react-scripts 2.0 breaks some monorepos

[bradfordlemley]

Is this a bug report?

Yes

Description

Certain monorepos (e.g. ones with nwb components) are incompatible with react-scripts 2.0, which means that certain existing monorepos (that currently work with react-scripts 1.0) will be broken with react-scripts 2.0.

This is because the current react-scripts 2.0 treats all packages in the monorepo that are included by the app as source packages (transpiled, linted, and tested), and there is no mechanism for opting them in or out.

The following issues are a result of not being able to opt packages in/out:

• jest runs all tests found in monorepo react-scripts@2.0.0-next #4410 (react-scripts test fails if monorepo contains incompatible tests)
• next@b2fd8db8 throws if monorepo with nwb modules #4249 (react-scripts build fails w/ nwb module in monorepo)

Steps to Reproduce

See issues above.

Reproducible Demo

See issues above, or:
https://github.com/bradfordlemley/cra-monorepo-examples/tree/optin

[gaearon]

Is #4092 sufficient to fix this?

[bradfordlemley]

Yes, #4092 would fix this. #4570 is an alternative fix, added #4092 (comment) as discussion on the alternative fixes.

[bebbi]

@gaearon @bradfordlemley I read #4092 again and think the required private mark still conflicts with the #4249 case, see this comment

[Timer]

Reverted for 2.0 release.