fix(playwright): auto-install Playwright browsers via prepare script

[jycouet]

Closes #1038

Description

Add playwright install in prepare script to make sure we are ready to test:e2e

Checklist

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[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-cli-1041-svelte.vercel.app/

[sacrosanctic]

https://docs.npmjs.com/cli/v8/using-npm/scripts

• prepare (since npm@4.0.0)
• Runs any time before the package is packed, i.e. during npm publish and npm pack
• Runs BEFORE the package is packed
• Runs BEFORE the package is published
• Runs on local npm install without any arguments
• Run AFTER prepublish, but BEFORE prepublishOnly
• NOTE: If a package being installed through git contains a prepare script, its dependencies and devDependencies will be installed, and the prepare script will be run, before the package is packaged and installed.
• As of npm@7 these scripts run in the background. To see the output, run with: --foreground-scripts.

Is the prepare script really appropriate? Wouldn't this run during CI? (As a side note, pnpm exec playwright install doesn't work on novel flavours of Linux like NixOS)

[jycouet]

I guess that if you have e2e tests you will want to have it in CI. And if in your CI you install playwright in a previous step, this will just pick from cache and all good.

I don't know NixOS, I should look 👀. How people will test then?

[sacrosanctic]

I don't know NixOS, I should look 👀. How people will test then?

They use a seperate package manager to install it. It was a throwaway comment, not a blocker.

[jycouet]

I still want to see the behavior there 👍
Will look later

[jycouet]

I installed nixos to see, an I get:

[nix-shell:~/s01]$ npx playwright install
BEWARE: your OS is not officially supported by Playwright; downloading fallback build for ubuntu24.04-x64.
BEWARE: your OS is not officially supported by Playwright; downloading fallback build for ubuntu24.04-x64.
BEWARE: your OS is not officially supported by Playwright; downloading fallback build for ubuntu24.04-x64.
BEWARE: your OS is not officially supported by Playwright; downloading fallback build for ubuntu24.04-x64.
BEWARE: your OS is not officially supported by Playwright; downloading fallback build for ubuntu24.04-x64.
Playwright Host validation warning:
╔══════════════════════════════════════════════════════╗
║ Host system is missing dependencies to run browsers. ║
║ Missing libraries:                                   ║
║     libstdc++.so.6                                   ║
║     libxcb-shm.so.0                                  ║
║     libX11-xcb.so.1                                  ║
║     libXrandr.so.2                                   ║
║     libXcomposite.so.1                               ║
║     libXcursor.so.1                                  ║
║     libXdamage.so.1                                  ║
║     libXi.so.6                                       ║
║     libXext.so.6                                     ║
║     libXfixes.so.3                                   ║
║     libX11.so.6                                      ║
║     libxcb.so.1                                      ║
║     libgtk-3.so.0                                    ║
║     libgdk-3.so.0                                    ║
║     libpangocairo-1.0.so.0                           ║
║     libpango-1.0.so.0                                ║
║     libatk-1.0.so.0                                  ║
║     libcairo-gobject.so.2                            ║
║     libcairo.so.2                                    ║
║     libgdk_pixbuf-2.0.so.0                           ║
║     libgio-2.0.so.0                                  ║
║     libgobject-2.0.so.0                              ║
║     libglib-2.0.so.0                                 ║
║     libXrender.so.1                                  ║
║     libasound.so.2                                   ║
║     libfreetype.so.6                                 ║
║     libfontconfig.so.1                               ║
║     libdbus-1.so.3                                   ║
╚══════════════════════════════════════════════════════╝
    at validateDependenciesLinux (/home/nixos/s01/node_modules/playwright-core/lib/server/registry/dependencies.js:269:9)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async Registry._validateHostRequirements (/home/nixos/s01/node_modules/playwright-core/lib/server/registry/index.js:962:14)
    at async Registry._validateHostRequirementsForExecutableIfNeeded (/home/nixos/s01/node_modules/playwright-core/lib/server/registry/index.js:1084:7)
    at async Registry.validateHostRequirementsForExecutablesIfNeeded (/home/nixos/s01/node_modules/playwright-core/lib/server/registry/index.js:1073:7)
    at async installBrowsers (/home/nixos/s01/node_modules/playwright-core/lib/cli/installActions.js:145:5)
    at async i.<anonymous> (/home/nixos/s01/node_modules/playwright-core/lib/cli/program.js:63:5)

What's really annoying is that Playwright is not doing a great job spiting this gigantic error!
And it's more or less the same if you didn't install, no matter the shell/os.

I'm hesitant to know how good/bad is it to put in prepare script.

[sacrosanctic]

Original problem was playwright printing too much junk. Maybe this is more of an upstream issue and we should just print a msg in the console.

[Rich-Harris]

My 2c: if you have e2e tests and you're not running them in CI, you're Doing It Wrong. And if you can't run them in CI because you're using NixOS, then the solution to that is stop using NixOS