Handling Duplicate Markers in GLSP and Langium Integration

[kapishsingla]

Hi Team,

I am currently working with Langium and GLSP, where I am implementing validation on the Langium model, which should be displayed on the GLSP node. In the ProblemManager, both GLSP and Langium are registering markers, resulting in each error being shown twice in both the navigator and the problem view.

One potential approach is to filter diagnostics based on the owner, but this doesn’t seem like the most optimal solution. What would be a better approach to achieve this?

[msujew]

Hey @kapishsingla,

I'm not quite sure to be honest. On an architectural level, both Langium and GLSP simply send diagnostics to Theia, which are correctly displayed. Therefore, it might make sense to prevent one of those (either Langium or GLSP) from sending their diagnostics to the language client. I'm not quite sure how easy it is to prevent GLSP from sending its diagnostics, but it should be doable in Langium by creating a custom startLanguageServer function that doesn't register the addDiagnosticsHandler function.

[martin-fleck-at]

Alternatively, you can disable the GLSP marker registration as mentioned here: eclipse-glsp/glsp#1487 (comment)