Don't try to run scripts that aren't defined

[peterlebrun]

Fixes #6739

This is my first pull request with yarn (I love yarn, I got my whole company on it!), so please let me know if I've missed anything from the contributing instructions.

Right now, yarn workspaces run script will exit with error if script is not defined in all workspaces. This is because yarn workspaces run naively spawns a child process without determining if the script exists. This pull request checks that the script exists in the workspace before attempting to spawn a new child process to run the script.

I also output the workspace name before each command attempt, so that we can keep track of where the script does/doesn't exist.

I have added unit tests, and tested it within yarn/packages/pkg-tests:

[eps1lon]

This also includes a fix for #6389

[peterlebrun]

@eps1lon following discussion with @arcanis I have removed changes relating to the workspace names. I will submit a separate PR for issue #6389.

At this point, this PR only addresses issue #6739.

[buildsize]

File name	Previous Size	New Size	Change
yarn-[version].noarch.rpm	1.11 MB	1.11 MB	342 bytes (0%)
yarn-[version].js	4.47 MB	4.47 MB	1.2 KB (0%)
yarn-legacy-[version].js	4.66 MB	4.66 MB	1.24 KB (0%)
yarn-v[version].tar.gz	1.12 MB	1.12 MB	-330 bytes (0%)
yarn_[version]all.deb	815.78 KB	815.68 KB	-96 bytes (0%)

[peterlebrun]

@arcanis I have updated this PR to work with yarn workspaces run -s exec ...

[markuskobler]

Is anything else needed to get this merged?

[arcanis]

Mostly time for me to review it. I plan to make a review pass tomorrow.

[TerribleDev]

@arcanis what can we do to get this over the line? 🚗

[rally25rs]

This change results in a problem where installed binaries can no longer be run in workspaces. For example if your packages use jest for unit testing, you can no longer yarn workspaces run jest

example:

~/Projects/yarn-test2 🐒   yarn workspace pkg1 add jest --dev
yarn workspace v1.16.0-0
yarn add v1.16.0-0
[1/4] 🔍  Resolving packages...
[2/4] 🚚  Fetching packages...
[3/4] 🔗  Linking dependencies...
warning "workspace-aggregator-84402bc9-4dfe-4818-a7ac-77ec7e134aa0 > jest > jest-cli > @jest/core > [email protected]" has unmet peer dependency "jest-resolve@^24.1.0".
warning "workspace-aggregator-84402bc9-4dfe-4818-a7ac-77ec7e134aa0 > jest > jest-cli > jest-config > [email protected]" has unmet peer dependency "jest-haste-map@^24.0.0".
[4/4] 🔨  Building fresh packages...

success Saved 1 new dependency.
info Direct dependencies
info All dependencies
└─ [email protected]
✨  Done in 8.31s.
✨  Done in 8.61s.

existing yarn:

~/Projects/yarn-test2 🐒   yarn workspaces run jest
yarn workspaces v1.13.0
yarn run v1.13.0
$ /Users/jvalore/Projects/yarn-test2/packages/pkg1/node_modules/.bin/jest
 PASS  ./some.test.js
  pkga
    ✓ has tests (4ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        0.998s, estimated 1s
Ran all test suites.
✨  Done in 1.64s.
✨  Done in 2.02s.

with this change:

~/Projects/yarn-test2 🐒   yarn workspaces run jest
yarn workspaces v1.16.0-0
warning No scripts defined in workspace pkg1.
✨  Done in 0.09s.