Uast: KotlinSecondaryConstructorWithInitializersUMethod introduced as workaround for KT-21617

to be the only constructor which includes `init` block when there is no primary constructors in the class

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/declarations/KotlinUClass.kt

@@ -81,11 +81,16 @@ open class KotlinUClass private constructor(
     override fun getInitializers(): Array<UClassInitializer> = super.getInitializers()
 
     override fun getMethods(): Array<UMethod> {
+        val hasPrimaryConstructor = ktClass?.hasPrimaryConstructor() ?: false
+        var secondaryConstructorsCount = 0
 
         fun createUMethod(psiMethod: PsiMethod): UMethod {
             return if (psiMethod is KtLightMethod &&
                        psiMethod.isConstructor) {
-                KotlinConstructorUMethod(ktClass, psiMethod, this)
+                if (!hasPrimaryConstructor && secondaryConstructorsCount++ == 0)
+                    KotlinSecondaryConstructorWithInitializersUMethod(ktClass, psiMethod, this)
+                else
+                    KotlinConstructorUMethod(ktClass, psiMethod, this)
             } else {
                 getLanguagePlugin().convert(psiMethod, this)
             }
@@ -111,7 +116,7 @@ open class KotlinUClass private constructor(
     }
 }
 
-class KotlinConstructorUMethod(
+open class KotlinConstructorUMethod(
         private val ktClass: KtClassOrObject?,
         override val psi: KtLightMethod,
         givenParent: UElement?
@@ -143,17 +148,28 @@ class KotlinConstructorUMethod(
         }
     }
 
-    private fun getBodyExpressions(): List<KtExpression> {
+    open protected fun getBodyExpressions(): List<KtExpression> {
         if (isPrimary) return getInitializers()
         val bodyExpression = (psi.kotlinOrigin as? KtFunction)?.bodyExpression ?: return emptyList()
         if (bodyExpression is KtBlockExpression) return bodyExpression.statements
         return listOf(bodyExpression)
     }
 
-    private fun getInitializers() = ktClass?.getAnonymousInitializers()?.mapNotNull { it.body } ?: emptyList()
+    protected fun getInitializers() = ktClass?.getAnonymousInitializers()?.mapNotNull { it.body } ?: emptyList()
 
 }
 
+// This class was created as a workaround for KT-21617 to be the only constructor which includes `init` block
+// when there is no primary constructors in the class.
+// It is expected to have only one constructor of this type in a UClass.
+class KotlinSecondaryConstructorWithInitializersUMethod(
+        ktClass: KtClassOrObject?,
+        psi: KtLightMethod,
+        givenParent: UElement?
+) : KotlinConstructorUMethod(ktClass, psi, givenParent) {
+    override fun getBodyExpressions(): List<KtExpression> = getInitializers() + super.getBodyExpressions()
+}
+
 class KotlinUAnonymousClass(
         psi: PsiAnonymousClass,
         givenParent: UElement?

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/expressions/KotlinUBlockExpression.kt

@@ -44,4 +44,16 @@ class KotlinUBlockExpression(
             }
         }
     }
+
+    override fun convertParent(): UElement? {
+        val directParent = super.convertParent()
+        if (directParent is UnknownKotlinExpression && directParent.psi is KtAnonymousInitializer) {
+            val containingUClass = directParent.getContainingUClass() ?: return directParent
+            containingUClass.methods
+                    .find { it is KotlinConstructorUMethod && it.isPrimary || it is KotlinSecondaryConstructorWithInitializersUMethod }?.let {
+                return it.uastBody
+            }
+        }
+        return directParent
+    }
 }

plugins/uast-kotlin/testData/Constructors.kt

@@ -58,8 +58,6 @@ class AWithSecondaryInit {
     lateinit var a: String
 
     init {
-        // This body will not be picked by UAST because no lightMethod contains it.
-        // Of course it is not a desired behaviour, so fix it if you know how
         println()
     }
 

plugins/uast-kotlin/testData/Constructors.log.txt

@@ -130,6 +130,10 @@ UFile (package = )
                 UCallExpression (kind = UastCallKind(name='constructor_call'), argCount = 0))
                     UIdentifier (Identifier ())
                     USimpleNameReferenceExpression (identifier = <init>)
+                UBlockExpression
+                    UCallExpression (kind = UastCallKind(name='method_call'), argCount = 0))
+                        UIdentifier (Identifier (println))
+                        USimpleNameReferenceExpression (identifier = println)
                 UBinaryExpression (operator = =)
                     USimpleNameReferenceExpression (identifier = a)
                     UQualifiedReferenceExpression

plugins/uast-kotlin/testData/Constructors.render.txt

@@ -67,6 +67,9 @@ public final class AWithSecondaryInit {
     public final fun setA(p: java.lang.String) : void = UastEmptyExpression
     public fun AWithSecondaryInit(i: int) {
         <init>()
+        {
+            println()
+        }
         a = i.toString()
     }
     public fun AWithSecondaryInit(s: java.lang.String) {