Custom lint rule kotlin object - kotlin

Question

I'm trying to create a custom lint rule in order to avoid using a kotlin object class.
object AColors {
val white: Color = Color(0xFFFFFFFF)
}
fun main() {
val myColor = AColors.white //Lint error : Do not use AColors
}
How can I manage to get a lint issue when AColors is used?
In my case, AColors can't be private because I need it for a specific case.
I tried to create a custom lint rule to check the import but this is not a bullet-proof solution as you can use AColors without importing anything
class InvalidImportHandler(private val context: JavaContext) : UElementHandler() {
override fun visitImportStatement(node: UImportStatement) {
//check the import
}
}

Answer 1

For this specific case, you may check for USimpleNameReferenceExpressions and then check if the reference is to the AColors class. Like so:
class AColorsReferenceDetector : Detector(), Detector.UastScanner {
override fun getApplicableUastTypes(): List<Class<out UElement>> {
return listOf(USimpleNameReferenceExpression::class.java)
}
override fun createUastHandler(context: JavaContext): UElementHandler {
return object : UElementHandler() {
override fun visitSimpleNameReferenceExpression(
node: USimpleNameReferenceExpression
) {
val element = node.resolve()?.unwrapped
if (element is KtObjectDeclaration && element.name == "AColors") {
context.report(
ISSUE,
node,
context.getLocation(node.uastParent)
)
}
}
}
}
companion object {
val ISSUE = Issue.create(
AColorsReferenceDetector::class.simpleName.orEmpty(),
"Do not use AColors",
"Do not use AColors",
Category.CORRECTNESS,
10,
Severity.ERROR,
Implementation(
AColorsReferenceDetector::class.java,
EnumSet.of(Scope.JAVA_FILE)
)
)
}
}
Example IssueRegistry:
class IssueRegistry : IssueRegistry() {
override val api = CURRENT_API
override val minApi: Int
get() = 8
override val vendor: Vendor = Vendor()
override val issues
get() = listOf(AColorsReferenceDetector.ISSUE)
}
Example result: