Allow recent created files to be imported

[ericdallo]

Describe the bug
when using lsp-mode with dart-mode, after I create a new dart file, when I try to use it, it just don't show an option on lsp-ui for the auto import.
Sometimes if I run lsp-restart-workspace then lsp again, or I kill the buffer, the option to import shows off.

To Reproduce
Example:

I create a file b.dart:

class B {

}

then on an existent file a.dart, lsp-ui doesn't recognize the class to import:

void main() {
    final b = B();
}

the only options are:

Expected behavior
Like lsp-java I expect it to recognize the new file/class and allows me to import it.

Which Language Server did you use
lsp-dart

OS
Which os do you use?
NixOS 20.03

Error callstack

[itome]

I'm seeing same issue, and when I checked this in VSCode it works fine.
But lsp-mode with typescript-language-server also works fine with recent created files.

[yyoncho]

Not sure if it is the same issue but in the past I have investigated similar issue. It was caused by the fact that emacs creates files in memory while vscode touches them on the disk. Can you try touch file.foo from the command line and then opening it in emacs? If it works - the issue is on the server.

[itome]

It seems that auto import is not working even with file that is create by touch command.

[ericdallo]

I was able to confirm that the problem is on server.

$ touch b.dart
$ echo 'class B { }' > b.dart

Then in a.dart, it shows an option to import b.dart

[ericdallo]

@yyoncho, so do you think I should open an issue on upstream?
It's odd, since creating the file via the terminal as I said above, works great. Isn't this a lsp-mode bug?

[yyoncho]

Here it is the spec:

The document open notification is sent from the client to the server to signal newly opened text documents. The document’s content is now managed by the client and the server must not try to read the document’s content using the document’s Uri.

The server should work without depending on the file present on the disc or not.

[ericdallo]

It makes totally sense, a weird behavior too, is that evenly saving the buffer before or after creating the B class, it does not work

[DanTup]

This might be the same issue shown here:

Dart-Code/Dart-Code#2286 (comment)

Which should be fixed by:

https://dart-review.googlesource.com/c/sdk/+/154960/

[ericdallo]

Thanks, @DanTup, I'll try to reproduce the issue with the fix...

[ericdallo]

I could confirm that this is fixed on the latest SDK: http://gsdview.appspot.com/dart-archive/channels/be/raw/latest/sdk/
Thank you very much @DanTup!