Tracking: Using spawn vs. exec as underlying process mechanism

[exogen]

In investigating FormidableLabs/radium#420, I'm beginning to suspect that the users' shell configuration is a contributing factor. For example, you can configure your shell in a strict mode so that if any command fails in a cmd1 || cmd2 chain, the whole command still fails, as if they were joined with &&. It's possible these people have some global setting that's causing the || to fail (yes, even though NPM attempts to run your script with plain old sh).

Anyway, whether or not that is the issue, I dug into how npm runs scripts, and found that they use spawn (they wrap Node's spawn slightly). In order to not have to parse the command, they run sh -c which takes the shell command to run as a string.

While I'm fine with exec, I thought I'd bring this back up because it's a difference in how Builder runs your script vs. NPM – and I anticipate that difference being a source of issues and confusion in a future where Builder is used more widely.

(We can put this off for now, just thought I'd add it as a TODO.)

[ryan-roemer]

@exogen -- Yep, I'm familiar with the internals of npm run and they do use spawn.

We'll keep this issue open and icebox'ed for tracking. Thanks!