Reading svelte config from vite.config.js/ts files introduced in 4.6.0 seems flawed

[scottohara]

Describe the bug

With reference to these issues/PRs:

• feat: support reading Svelte config from vite.config.js/ts #3031 (initial change introduced in 4.6.0)
• svelte-check: Config loader crawls vendor/ directory and logs non-fatal errors for unrelated vite.config.js files #3054 (bug report related to the change)
• feat: enable passing Svelte config file paths #3066 (fix introduced in 4.7.0)

It would seem that the short term "fix" was to allow a config file path to be explicitly provided to turn off recursive crawling, and a longer term "TODO" for the next major was mentioned:

We should not recursively crawl for config files anymore if we find one in the root directory or next to the tsconfig.

I'm not sure either the short term fix or long term TODO fixes the following scenario:
(if it does, please let me know how)

Reproduction

Assume the following monorepo style layout:

packages/
  package-a/    // this package does not use svelte or @sveltejs/vite-plugin-svelte
    vite.config.ts
  package-b/    // this package does use svelte and @sveltejs/vite-plugin-svelte
    vite.config.ts
  tsconfig.json    // shared tsconfig.json file used by all packages

With svelte-check@4.5.0, running svelte-check from the project root runs successfully:

Loading svelte-check in workspace: [REDACTED]
Getting Svelte diagnostics...

svelte-check found 0 errors and 0 warnings

...and just to be sure that it is actually checking, if I deliberately introduce an issue it correctly errors:

Loading svelte-check in workspace: [REDACTED]
Getting Svelte diagnostics...

[REDACTED]/packages/package-b/components/Foo.svelte:5:6
Error: 'foo' is declared but its value is never read. (ts)

        let foo = "";
</script>
====================================
svelte-check found 1 error and 0 warnings in 1 file

With svelte-check@4.6.0, running svelte-check from the project root now reports:

Error while loading config at  [REDACTED]/packages/package-a/vite.config.ts
Error: No Svelte configuration found in vite config. Is @sveltejs/vite-plugin-svelte configured?
    at ConfigLoader.loadConfig ([REDACTED]/node_modules/svelte-check/dist/src/index.js:40183:13)
Loading svelte-check in workspace: [REDACTED]
Getting Svelte diagnostics...

svelte-check found 0 errors and 0 warnings

Note that the error is complaining about package-a, which does not use svelte.

With svelte-check@4.7.0, running svelte-check --config packages/package-b/vite.config.ts from the project root suppresses the error.

However that only works because there is only one package in the repo that uses svelte.
How would this work if there was also a third package that used svelte, e.g.

packages/
  ...
  package-c/    // also uses svelte and @sveltejs/vite-plugin-svelte
    vite.config.ts

Would I need to run svelte-check separately for each package, passing the correct path to the vite.config.ts for that package?, e.g.

svelte-check --config packages/package-b/vite.config.ts && svelte-check --config packages/package-c/vite.config.ts

If we assume the long term TODO happens, note that my vite.config.ts files are neither in the root, nor are they adjacent to a tsconfig file, so it's not clear whether that would work here either.

Expected behaviour

In 4.5.0, running svelte-check at the root of a monorepo where individual packages may or may not use svelte would check successfully.

In 4.6.0 and later, that now errors unless a path to one of the package's vite.config.ts is specified, but it is not clear how this works when there are >1 svelte packages mixed with >1 non-svelte packages, each with their own vite.config.ts and a shared tsconfig in a parent directory.

System Info

• OS: [e.g. Windows] macOS
• IDE: [e.g. VSCode, Atom] VSCode

Which package is the issue about?

svelte-check

Additional Information, eg. Screenshots

No response