create-react-app: Can't use NODE_PATH with two directories

Is this a bug report?

Yes

Can you also reproduce the problem with npm 4.x?

Did not try

Which terms did you search for in User Guide?

NODE_PATH, indexOf, undefined

Environment

1. node -v: v8.7.0
2. npm -v: 5.6.0
3. yarn --version (if you use Yarn):
4. npm ls react-scripts (if you haven’t ejected):

Then, specify:

1. Operating system: MacOS
2. Browser and version (if relevant): N/A

Steps to Reproduce

(Write your steps here:)

1. Create a .env file in the root folder. Add NODE_PATH to it containing two directories: NODE_PATH=src:../shared
2. Run npm start. You will get the following error:

/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/react-dev-utils/ModuleScopePlugin.js:28
        request.descriptionFileRoot.indexOf('/node_modules/') !== -1 ||
                                    ^

TypeError: Cannot read property 'indexOf' of undefined
    at Resolver.resolver.plugin (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/react-dev-utils/ModuleScopePlugin.js:28:37)
    at Resolver.applyPluginsAsyncSeriesBailResult1 (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/tapable/lib/Tapable.js:256:13)
    at runNormal (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:130:20)
    at Resolver.doResolve (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:116:3)
    at Resolver.<anonymous> (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/TryNextPlugin.js:16:12)
    at Resolver.applyPluginsAsyncSeriesBailResult1 (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/tapable/lib/Tapable.js:256:13)
    at runNormal (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:130:20)
    at Resolver.doResolve (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:116:3)
    at Resolver.<anonymous> (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/FileKindPlugin.js:17:12)
    at Resolver.applyPluginsAsyncSeriesBailResult1 (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/tapable/lib/Tapable.js:256:13)
    at runNormal (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:130:20)
    at Resolver.doResolve (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:116:3)
    at Resolver.<anonymous> (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/NextPlugin.js:14:12)
    at Resolver.applyPluginsAsyncSeriesBailResult1 (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/tapable/lib/Tapable.js:256:13)
    at runAfter (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:152:20)
    at innerCallback (/Users/nbhati/projects/myapp-monorepo/myapp-embeds/node_modules/enhanced-resolve/lib/Resolver.js:146:3)

Expected Behavior

App is able to build correctly using packages from src and ../shared

Actual Behavior

Build crashes with TypeError: Cannot read property 'indexOf' of undefined

Reproducible Demo

None