Ensure that child build processes started when running on Windows exit properly.

[pkaminski]

Changes

plugin-run-script and plugin-build script use execa.command with the shell: true option set to execute the user's command. On Windows, this causes the child process to remain running after Snowpack exits: sindresorhus/execa#433. The fix is to override the default windowsHide option -- as Snowpack always runs from a console we don't actually need execa to hide any extra console windows for us.

Testing

Tested on my project's build with a few plugin-run-script instances by keeping an eye on the process list before/after running Snowpack. I don't immediately see how to automate testing the issue...

---

This change is 

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/pikapkg/snowpack/hyx19jjxl
✅ Preview: Canceled

[FredKSchott]

+1 as long as you can confirm that this doesn't make the general user experience any worse. You're saying that windowHide doesn't make a difference here since you run snowpack as a CLI anyway? That doesn't change if you run Snowpack in some integrated terminal, like a terminal built-into your code editor?

@stramel would love your help testing this manually on windows if you can!

[pkaminski]

FWIW, I tried running Snowpack (with the patch) from VSCode's built-in terminal and everything worked fine: no anomalous windows popped open, and all processes exited correctly.

Even if there is some corner case where it makes the UX worse, though, I think the alternative of leaving a zombie Node process around for each run or build script configured every time you run Snowpack is worse. I had 30+ of these zombies by the time I coincidentally happened to check my process list... The only other option I can think of is to find some better fix than the execa folks could, but that is definitely beyond my skills.

[FredKSchott]

LGTM! Thanks for investigating this fix 👍