Code action for unresolved references

[theogiraudet]

Hi!

I have a language with an import mechanism (such as the file-based scoping example). I want to propose import detection as a quick fix into my code action provider.
However, I don't get the impression that resolving references triggers a diagnostic.
Is there a way to offer this kind of functionality?

Thanks!

[cdietrich]

Hi, are you sure you have a cross reference for the place you don’t get a diagnostic for? Can you provide a sample grammar / playground

[theogiraudet]

Here is a short extract of my grammar:

entry Model returns Module:
    'module' name=QualifiedName
    imports += Import*
    namespaces += Classifier*;

Classifier returns Classifier:
  Entity;

Import returns Import:
    'import' '{' (imported += ClassifierImport (',' imported += ClassifierImport)*) '}' 'from' fromModule=[Module:QualifiedName];

ClassifierImport returns ClassifierImport:
    imported=[Classifier:ID] ('as' alias=ID)?;

Entity returns Entity:
    documentation=Documentation? 'entity' name=ID '{' members += Member* '}';

Member returns Member:
  ReferenceMember;

ReferenceMember returns ReferenceMember:
    "contains" name=ID ':' referenceType=ReferenceType;

ReferenceType returns ReferenceType:
    ref=[Entity:QualifiedName];

So according to my grammar, this is a cross-reference.
I made an empty code action service and placed a breakpoint inside. My service wasn't called when Langium failed to resolve the cross-reference (due to my scoping rules).
Since here I would like to catch a failure coming from Langium and not from custom validation rules, I wasn't really surprised by this behavior. But maybe this should work?

[cdietrich]

Which client do you use ? Is the Code Action request sent ?

[cdietrich]

And what do you do in the client to trigger the Code Action Service

[cdietrich]

And how does your Code Action provider look like and how do you bind it. Just tried with a hello world and mine gets called

[theogiraudet]

Okay, I'm confused this is my fault, I just forgot to plug my service inside the module file.
I was convinced that the code actions of Langium were done for validation so that reports coming from Langium itself were not transmitted to the code action provider. Thank you very much for your help, and sorry for the inconvenience!

[msujew]

Hey @theogiraudet, good to see you :)

We actually have something like this in the Langium grammar language server:

langium/packages/langium/src/grammar/lsp/grammar-code-actions.ts

Lines 82 to 90 in 23d4a14

	case DocumentValidator.LinkingError: {
	const data = diagnostic.data as LinkingErrorData;
	if (data && data.containerType === 'RuleCall' && data.property === 'rule') {
	accept(this.addNewRule(diagnostic, data, document));
	}
	if (data) {
	this.lookInGlobalScope(diagnostic, data, document).forEach(accept);
	}
	break;

In this case we simply create a new rule, but the same architecture can be used to instead create an import. For the import, you'll probably need to take a look at the index manager to figure out whether there's something that could fit the reference text.

[theogiraudet]

Hey Mark, yeah, I try to continue my personal projects based on Langium when I have a bit of time!
Thank you very much for the pointer, I will look at it to create my imports :)