[K2] Fix functional type and improve logging for unresolved link (#3157)

* [K2] Fix functional type and improve logging for unresolved link

For example
`typealias CompletionHandler = (cause: Throwable?) -> Unit`
has a functional type with no type arguments in K2. In K1 we have a usual generic type

7 files changed, 65 insertions, 26 deletions

diff --git a/plugins/base/src/test/kotlin/translators/ExternalDocumentablesTest.kt b/plugins/base/src/test/kotlin/translators/ExternalDocumentablesTest.kt
index 198ffe8e..5dd62545 100644
--- a/plugins/base/src/test/kotlin/translators/ExternalDocumentablesTest.kt
+++ b/plugins/base/src/test/kotlin/translators/ExternalDocumentablesTest.kt
@@ -14,7 +14,6 @@ import org.jetbrains.dokka.plugability.querySingle
 import org.jetbrains.dokka.utilities.cast
 import kotlin.test.Test
 import kotlin.test.assertEquals
-import utils.OnlyDescriptors
 import utils.UsingJDK
 
 class ExternalDocumentablesTest : BaseAbstractTest() {
@@ -61,10 +60,6 @@ class ExternalDocumentablesTest : BaseAbstractTest() {
         }
     }
 
-
-    // typealias CompletionHandler = (cause: Throwable?) -> Unit
-    // FunctionalTypeConstructor(dri=kotlinx.coroutines/CompletionHandler///PointingToDeclaration/, projections=[], isExtensionFunction=false, isSuspendable=false, presentableName=null, extra=PropertyContainer(map={}))
-    @OnlyDescriptors(reason = "FunctionType has not parameters") // TODO
     @Test
     fun `external documentable from dependency`() {
         val coroutinesPath =
diff --git a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/KDocProvider.kt b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/KDocProvider.kt
index 9dd6857e..d8a4e476 100644
--- a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/KDocProvider.kt
+++ b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/KDocProvider.kt
@@ -64,7 +64,7 @@ internal fun KtAnalysisSession.getKDocDocumentationFrom(symbol: KtSymbol, logger
 
     parseFromKDocTag(
         kDocTag = kDocContent.contentTag,
-        externalDri = { link -> resolveKDocLink(link).logIfNotResolved(link.getLinkText(), logger) },
+        externalDri = { link -> resolveKDocLink(link).ifUnresolved { logger.logUnresolvedLink(link.getLinkText(), kdocLocation) } },
         kdocLocation = kdocLocation
     )
 }
diff --git a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/ResolveKDocLink.kt b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/ResolveKDocLink.kt
index be06d595..9a0b81bd 100644
--- a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/ResolveKDocLink.kt
+++ b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/ResolveKDocLink.kt
@@ -15,15 +15,24 @@ import org.jetbrains.kotlin.kdoc.psi.impl.KDocLink
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocName
 import org.jetbrains.kotlin.psi.KtPsiFactory
 
-internal fun DRI?.logIfNotResolved(link: String, logger: DokkaLogger): DRI? {
-    if(this == null)
-    logger.warn("Couldn't resolve link for $link")
-    return this
+/**
+ * Util to print a message about unresolved [link]
+ */
+internal fun DokkaLogger.logUnresolvedLink(link: String, location: String?) {
+    warn("Couldn't resolve link for $link" + if (location != null) " in $location" else "")
+}
+
+internal inline fun DRI?.ifUnresolved(action: () -> Unit): DRI? = this ?: run {
+    action()
+    null
 }
 
 /**
- * It resolves KDoc link via creating PSI.
+ * Resolves KDoc link via creating PSI.
+ * If the [link] is ambiguous, i.e. leads to more than one declaration,
+ * it returns deterministically any declaration.
  *
+ * @return [DRI] or null if the [link] is unresolved
  */
 internal fun KtAnalysisSession.resolveKDocTextLink(link: String, context: PsiElement? = null): DRI? {
     val psiFactory = context?.let { KtPsiFactory.contextual(it) } ?: KtPsiFactory(this.useSiteModule.project)
@@ -38,9 +47,15 @@ internal fun KtAnalysisSession.resolveKDocTextLink(link: String, context: PsiEle
     return kDocLink?.let { resolveKDocLink(it) }
 }
 
+/**
+ * If the [link] is ambiguous, i.e. leads to more than one declaration,
+ * it returns deterministically any declaration.
+ *
+ * @return [DRI] or null if the [link] is unresolved
+ */
 internal fun KtAnalysisSession.resolveKDocLink(link: KDocLink): DRI? {
     val lastNameSegment = link.children.filterIsInstance<KDocName>().lastOrNull()
     val linkedSymbol = lastNameSegment?.mainReference?.resolveToSymbols()?.firstOrNull()
-    return if (linkedSymbol == null) null // logger.warn("Couldn't resolve link for $link")
+    return if (linkedSymbol == null) null
     else getDRIFromSymbol(linkedSymbol)
 }
diff --git a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/java/KotlinDocCommentParser.kt b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/java/KotlinDocCommentParser.kt
index 7e2e2a59..33cc4305 100644
--- a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/java/KotlinDocCommentParser.kt
+++ b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/java/KotlinDocCommentParser.kt
@@ -8,10 +8,11 @@ import com.intellij.psi.PsiNamedElement
 import org.jetbrains.dokka.Platform
 import org.jetbrains.dokka.analysis.java.doccomment.DocComment
 import org.jetbrains.dokka.analysis.java.parsers.DocCommentParser
-import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.logIfNotResolved
-import org.jetbrains.dokka.analysis.kotlin.symbols.plugin.SymbolsAnalysisPlugin
+import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.*
+import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.logUnresolvedLink
 import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.parseFromKDocTag
 import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.resolveKDocLink
+import org.jetbrains.dokka.analysis.kotlin.symbols.plugin.SymbolsAnalysisPlugin
 import org.jetbrains.dokka.model.doc.DocumentationNode
 import org.jetbrains.dokka.plugability.DokkaContext
 import org.jetbrains.dokka.plugability.plugin
@@ -37,10 +38,11 @@ internal class KotlinDocCommentParser(
                 ?: sourceSets.first { it.analysisPlatform == Platform.jvm }
         }
         val kotlinAnalysis = context.plugin<SymbolsAnalysisPlugin>().querySingle { kotlinAnalysis }
+        val elementName = element.resolveDocContext.ktElement.name
         return analyze(kotlinAnalysis[sourceSet].mainModule) {
             parseFromKDocTag(
                 kDocTag = element.comment,
-                externalDri = { link -> resolveKDocLink(link).logIfNotResolved(link.getLinkText(), context.logger) },
+                externalDri = { link -> resolveKDocLink(link).ifUnresolved { context.logger.logUnresolvedLink(link.getLinkText(), elementName) } },
                 kdocLocation = null,
                 parseWithChildren = parseWithChildren
             )
diff --git a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/moduledocs/ModuleAndPackageDocumentationParsingContext.kt b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/moduledocs/ModuleAndPackageDocumentationParsingContext.kt
index 9b748da2..ef59aa33 100644
--- a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/moduledocs/ModuleAndPackageDocumentationParsingContext.kt
+++ b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/kdoc/moduledocs/ModuleAndPackageDocumentationParsingContext.kt
@@ -5,7 +5,8 @@
 package org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.moduledocs
 
 import org.jetbrains.dokka.DokkaConfiguration
-import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.logIfNotResolved
+import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.ifUnresolved
+import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.logUnresolvedLink
 import org.jetbrains.dokka.analysis.kotlin.symbols.plugin.KotlinAnalysis
 import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.moduledocs.ModuleAndPackageDocumentation.Classifier.Module
 import org.jetbrains.dokka.analysis.kotlin.symbols.kdoc.moduledocs.ModuleAndPackageDocumentation.Classifier.Package
@@ -32,20 +33,31 @@ internal fun ModuleAndPackageDocumentationParsingContext(
     sourceSet: DokkaConfiguration.DokkaSourceSet? = null
 ) = ModuleAndPackageDocumentationParsingContext { fragment, sourceLocation ->
 
-    if(kotlinAnalysis == null || sourceSet == null) {
+    if (kotlinAnalysis == null || sourceSet == null) {
         MarkdownParser(externalDri = { null }, sourceLocation)
     } else {
         val analysisContext = kotlinAnalysis[sourceSet]
-        analyze(analysisContext.mainModule) {
+        val contextPsi = analyze(analysisContext.mainModule) {
             val contextSymbol = when (fragment.classifier) {
                 Module -> ROOT_PACKAGE_SYMBOL
                 Package -> getPackageSymbolIfPackageExists(FqName(fragment.name))
             }
-
-            MarkdownParser(
-                externalDri = { resolveKDocTextLink(it, contextSymbol?.psi).logIfNotResolved(it, logger) },
-                sourceLocation
-            )
+            contextSymbol?.psi
         }
+        MarkdownParser(
+            externalDri = { link ->
+                analyze(analysisContext.mainModule) {
+                    resolveKDocTextLink(
+                        link,
+                        contextPsi
+                    ).ifUnresolved {
+                        logger.logUnresolvedLink(link, fragment.name.ifBlank { "module documentation" })
+                    }
+
+                }
+            },
+            sourceLocation
+        )
+
     }
 }
diff --git a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/AnnotationTranslator.kt b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/AnnotationTranslator.kt
index db2d14b8..faae08e2 100644
--- a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/AnnotationTranslator.kt
+++ b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/AnnotationTranslator.kt
@@ -111,7 +111,10 @@ internal class AnnotationTranslator {
                 DRI(packageName = "", classNames = ERROR_CLASS_NAME)
             )
 
-            KtUnsupportedAnnotationValue -> TODO()
+            KtUnsupportedAnnotationValue -> ClassValue(
+                "<Unsupported Annotation Value>",
+                DRI(packageName = "", classNames = ERROR_CLASS_NAME)
+            )
         }
 
     private fun getDRIFrom(enumEntry: KtEnumEntryAnnotationValue): DRI {
@@ -129,6 +132,7 @@ internal class AnnotationTranslator {
 
         /**
          * Functional types can have **generated** [ParameterName] annotation
+         * @see ParameterName
          */
         internal fun KtAnnotated.getPresentableName(): String? =
             this.annotationsByClassId(parameterNameAnnotation)
diff --git a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/TypeTranslator.kt b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/TypeTranslator.kt
index 66c699f7..7127cbdf 100644
--- a/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/TypeTranslator.kt
+++ b/subprojects/analysis-kotlin-symbols/src/main/kotlin/org/jetbrains/dokka/analysis/kotlin/symbols/translators/TypeTranslator.kt
@@ -52,7 +52,7 @@ internal class TypeTranslator(
             throw IllegalStateException("Expected type alias symbol in type")
     }
 
-    private fun KtAnalysisSession.toTypeConstructorFrom(classType: KtUsualClassType) =
+    private fun KtAnalysisSession.toTypeConstructorFrom(classType: KtNonErrorClassType) =
         GenericTypeConstructor(
             dri = getDRIFromNonErrorClassType(classType),
             projections = classType.ownTypeArguments.map { toProjection(it) },
@@ -91,7 +91,18 @@ internal class TypeTranslator(
             )
 
             is KtClassErrorType -> UnresolvedBound(type.toString())
-            is KtFunctionalType -> toFunctionalTypeConstructorFrom(type)
+            is KtFunctionalType -> {
+                /**
+                 * For example
+                 * `typealias CompletionHandler = (cause: Throwable?) -> Unit`
+                 * has functional type with no type arguments in K2
+                 * In K1 we have a usual generic type
+                 */
+                if (type.ownTypeArguments.isEmpty())
+                    toTypeConstructorFrom(type)
+                else
+                    toFunctionalTypeConstructorFrom(type)
+            }
             is KtDynamicType -> Dynamic
             is KtDefinitelyNotNullType -> DefinitelyNonNullable(
                 toBoundFrom(type.original)