How to apply a LineMarkerProviderDescriptor to a kotlin file outside of synced project modules?

Hi Eli,

Could you please share your implementation and your registration and plugin.xml?

Sure, I'll share it below.
 

Is there something you're looking for specifically with the implementation that might be wrong? I have used the debugger to validate that the getLineMarkerInfo function is never called in my implementation for kt files outside of a synced module, but it is called for synced kt files and works correctly there. We have another implementation for yaml files (registered in plugin.xml with language="yaml") and I have verified that that implementation is always invoked for yaml files, even if they are not in synced modules.

 The plugin.xml contains this for the registration:

<extensions defaultExtensionNs="com.intellij">

     <codeInsight.lineMarkerProvider
        language="kotlin"
        implementationClass="actions.trio.TrioLineMarkersProvider"/>

</extensions>

And the implementation looks something like this:

class TrioLineMarkersProvider : LineMarkerProviderDescriptor() {

    override fun getLineMarkerInfo(element: PsiElement): LineMarkerInfo<*>? {
        if (element !is KtClass || !(element.isTrioDeclaration() || element.isTrioUIClass())) {
            return null
        }

        val identifier = element.nameIdentifier ?: return null
        val filePath = element.containingFile.virtualFile.path
        val module = getContainingModule(File(filePath)) ?: return null
        val trioFqn = element.fqName?.toString() ?: return null
        val generatedTestItems = getGeneratedTestItems(module, element, trioFqn)

        return LineMarkerInfo(
            identifier,
            identifier.textRange,
            ICON,
            { TITLE },
            { event, _ ->
                showPopupOptions(
                    RelativePoint(event),
                    generatedTestItems,
                    module.gradleFullModuleName,
                    element.project,
                )
            },
            GutterIconRenderer.Alignment.LEFT,
            { TITLE },
        )
    }


    override fun getName(): String = TITLE

    override fun getIcon(): Icon = ICON

}

Hello. Indeed, Kotlin files are not highlighted if outside the project source roots, because they require project structure knowledge (dependent modules, set up sdks, etc) to be highlightable. XML files, on the other hand, are frequently stashed all other the place and can be meaningfully highlighted even outside project structure.

To enable line marker highlighting, please de-unload the module which contains Kotlin files in question.

Thanks for the response. I need a way to surface custom information in a kotlin file _without_ having it loaded. Is there any other mechanism from Intellij that I could use? The only one that I can think of is a banner, which is not ideal.

So you want to highlight a Kotlin file from the unloaded module? 
The inspections/annotators/line markers are disabled for these files. The only possibility I can think of is to register your own HighlightVisitor. The downside is that this api is too low-level and easy to get wrong.

Yes, that ‘s what I’d like to do. From reading just the file psi information and kotlin annotations we have enough information to surface the annotators we want to show - the project structure and other information is not necessary for our use case at all. Thank you for the information