Warn against colons in directories when running user-defined scripts

[foucdeg]

Do you want to request a feature or report a bug?
A feature (a warning)

What is the current behavior?

package.json:

{
  ...
  "dependencies": {
    "some-command": "latest"
  },
  "scripts": {
     "build": "some-command"
  }
}

cd /directory:name:with:colons/
yarn run build

Returns error: some-command: command not found

This is because yarn appends the full path to node_modules/.bin to the $PATH before running the script, in order for some-command to work. But in this case, the full path contains colons, which ends up breaking the system's parsing of the $PATH. The system silently skips the invalid parts of $PATH and some-command cannot be found.

What is the expected behavior?

First I looked up the way to escape a colon in $PATH, but it cannot be done.

So I suggest that yarn emits a warning before it attemps to run a user-defined script in a directory that contains colons. Such as:

Warning: the path to the current directory contains colons (:). This may break user-defined scripts that use a command from the local node_modules/.bin directory.

Please mention your node.js, yarn and operating system version.
node 10.15.0, yarn 1.16, macOS 10.14.5

Related : #3515

[chrisdothtml]

+1 to providing a warning as it's not at all clear to the user why the command doesn't work in this case

[kantord]

I would say it would be better if yarn refused to run in such a path altogether, as some core functionality will be completely broken in most real life situations.

[YodaLightsabr]

This would be really nice to have! I just ran into this problem and I think it would save other people, mostly inexperienced yarn users, a lot of time.