JavaKit: check each classPath element exists before starting VM

[lhoward]

Partial fix for #136: validate each classPath element by attempting to open it before starting VM. It would be more efficient to stat() it but SystemPackage lacks an abstraction for checking if a file exists, and we don't want to import Foundation.

[lhoward]

Todo: check open-ing a directory is portable (specifically on Windows).

[lhoward]

For sure, just thought avoiding Foundation was preferable. This won't pull in ICU?

[lhoward]

OK, use FoundationEssentials where possible.

[lhoward]

  enum JavaKitError: Error {
    case classPathNotFound(String)
  } 

maybe we move VMError under this?

[ktoso]

Yup that's the way, thank you

[ktoso]

Thanks for dealing with the nitpicks :)

[ktoso]

Suggested change

	case classPathEntryNotFound(entry: String, classPath: String)
	case classPathEntryNotFound(entry: String, classPath: [String])

[ktoso]

Fixing compilation

[lhoward]

Oh, it was supposed to be colonSeparatedClassPath – must have dropped that diff somehow. But I suppose the colon separation is an implementation detail. I'll do as you suggest above.

[ktoso]

If you do the "maintainers can edit" on the right I can more easily fix simple stuff like that :) There's a simple compilation error, see proposed fix.

[lhoward]

If you do the "maintainers can edit" on the right I can more easily fix simple stuff like that :) There's a simple compilation error, see proposed fix.

Hmm, weirdly I can't seem to find this checkbox...

[ktoso]

Hmm, don't see something like that? (pic from a different PR that I made)

[ktoso]

Either way, thank you merged :)

[lhoward]

Hmm, don't see something like that? (pic from a different PR that I made)

I think it might be because my fork was in my company repo (PADL) rather than personal. It's a bit hard to parse [1].

[1] https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork#

[ktoso]

Huh interesting, didn't realize this limitation.