URI based modules should be loaded using the FileSystem parsePath(URI)

[pmlopes]

consider the following script:

import ms from 'https://unpkg.com/@esm/ms';
// not really important after this line
// it's just to ensure that no code elimination
// hapens
console.log(ms('2 days')); 

When using a custom FileSystem the module string path will be passed to the API method:

public Path parsePath(String path) {
  // path will be: "https://unpkg.com/@esm/ms"
  ...
}

Instead of:

public Path parsePath(URI uri) {
  // never called
  ...
}

As URIs are valid for module locations the correct FileSystem method should be invoked. Also the API contract states that parsePath(String) should be invoked for resources with schema file which isn't the case in this example.

[eleinadani]

Thanks for the report! Should be fixed by https://github.com/graalvm/graaljs/commit/b978c76b59cc9fc90e30cd6599c21f6e1ab35b5e

[jazdw]

@pmlopes Did you have to implement a custom file system that supports https to get this to work?

[pmlopes]

Hi, not yet, it's on my to-do list. I do have a custom filesystem but this method wasn't working. So I still need to implement it now

[jazdw]

OK, no worries. There's some discussion in the issue linked above.

[jazdw]

@eleinadani This still doesn't seem to work in 20.2 despite your fix. com.oracle.truffle.js.runtime.objects.DefaultESModuleLoader#resolveImportedModule refuses to try and parse the path as a URI and instead calls resolveSibling().

This is with a custom FS and URI scheme.

Error in script "": java.nio.file.InvalidPathException: Illegal char <:> at index 9: filestore://public/nashorn_import.js
org.graalvm.polyglot.PolyglotException: java.nio.file.InvalidPathException: Illegal char <:> at index 9: filestore://public/nashorn_import.js
    at java.base/sun.nio.fs.WindowsPathParser.normalize(WindowsPathParser.java:182)
    at java.base/sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:153)
    at java.base/sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:77)
    at java.base/sun.nio.fs.WindowsPath.parse(WindowsPath.java:92)
    at java.base/sun.nio.fs.WindowsFileSystem.getPath(WindowsFileSystem.java:229)
    at java.base/java.nio.file.Path.resolveSibling(Path.java:574)
    at com.oracle.truffle.api.TruffleFile.resolveSibling(TruffleFile.java:595)
    at com.oracle.truffle.js.runtime.objects.DefaultESModuleLoader.resolveImportedModule(DefaultESModuleLoader.java:98)

[jazdw]

I think your tests work because the source is not a file?