Installing dependencies with only package.json (and lockfile) present fails

[Conduitry]

Describe the bug

As noted here, when dependencies are installed when only package.json (and a lockfile) are present results in a failure during @sveltejs/kit's prepare script, which runs svelte-kit sync, which expects a full app to be present. Installing in this way is common when using multi-stage Docker builds, to optimize layer caching.

Reproduction

1. Create a new project
2. Delete everything except package.json
3. Install dependencies

Logs

> You need to create a svelte.config.js file. See https://kit.svelte.dev/docs/configuration
    at load_config (file:///.../node_modules/.pnpm/@[email protected][email protected]/node_modules/@sveltejs/kit/dist/cli.js:780:9)
    at file:///.../node_modules/.pnpm/@[email protected][email protected]/node_modules/@sveltejs/kit/dist/cli.js:1000:25
    at o.parse (/.../node_modules/.pnpm/[email protected]/node_modules/sade/lib/index.js:1:3402)
    at file:///.../node_modules/.pnpm/@[email protected][email protected]/node_modules/@sveltejs/kit/dist/cli.js:1008:6
    at ModuleJob.run (node:internal/modules/esm/module_job:198:25)
    at async Promise.all (index 0)
    at async ESMLoader.import (node:internal/modules/esm/loader:385:24)
    at async loadESM (node:internal/process/esm_loader:88:5)
    at async handleMainPromise (node:internal/modules/run_main:61:12)

System Info

System:
    OS: Linux 5.10 Ubuntu 20.04.4 LTS (Focal Fossa)
    CPU: (8) x64 Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz
    Memory: 23.46 GB / 24.98 GB
    Container: Yes
    Shell: 5.0.17 - /bin/bash
  Binaries:
    Yarn: 1.22.15
    npm: 8.5.2
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.33
    @sveltejs/kit: next => 1.0.0-next.299
    svelte: ^3.46.0 => 3.46.4

Severity

blocking an upgrade

Additional Information

Making svelte-kit sync a no-op when there's no svelte.config.js might be a step in the right direction, but I'm not positive that would be enough.

Maybe, when using Docker, the next build stage would have to run svelte-kit sync before it runs svelte-kit build? I'm not sure whether sync does anything that build wouldn't.

[Conduitry]

It looks like making sync a no-op might in fact be enough. (Maybe it could print a warning, as long as it still has a 0 exit code.) Anything in .svelte-kit that sync would have generated is also generated by build (and by dev for that matter).