README.md

This gist reproduces a bug in Yarn v0.27.5.

The bug is caused by Yarn returning exit status 0 when a script inside the package.json "scripts" causes a segmentation fault.

This only happens when there is a single command in the script (e.g.: "test": "./segfault"). When there are several commands in the script (e.g.: "test-alt": "true && ./segfault") it returns an exit status 1.

This bug causes errors to be unnoticed in CI builds, where everything seems to be OK.

Steps to reproduce:

1. Download the gist.
2. Execute yarn run test ; echo "Exit status $?" to reproduce the issue.
3. Execute yarn run test-alt ; echo "Exit status $?" to reproduce a workaround for the issue.

package.json

{
  "name": "yarn-segfault",
  "version": "1.0.0",
  "scripts": {
    "compile": "gcc segfault.c -g -o segfault",
    "pretest": "yarn run compile",
    "test": "./segfault",
    "pretest-alt": "yarn run compile",
    "test-alt": "true && ./segfault"
  }
}

segfault.c

int main(void)
{
    char *s = "hello world";
    *s = 'H';
}