Fixed KT-5383 J2K: preserve annotations from primary constructor + never drop constructors with annotations

#KT-5383 Fixed

j2k/src/org/jetbrains/jet/j2k/ConstructorConverter.kt

@@ -121,12 +121,10 @@ class ConstructorConverter(private val psiClass: PsiClass, private val converter
     }
 
     private fun dropConstructorsForDefaultValues(primary: PsiMethod, toTargetConstructorMap: Map<PsiMethod, TargetConstructorInfo>) {
-        //TODO: should we drop when annotations exist?
-
         val dropCandidates = toTargetConstructorMap
                 .filter { it.value.parameterDefaults != null }
                 .map { it.key }
-                .filter { it.accessModifier() == primary.accessModifier() }
+                .filter { it.accessModifier() == primary.accessModifier() && it.getModifierList().getAnnotations().isEmpty() /* do not drop constructors with annotations */ }
                 .sortBy { -it.getParameterList().getParametersCount() } // we will try to drop them starting from ones with more parameters
         val primaryParamCount = primary.getParameterList().getParametersCount()
         @DropCandidatesLoop
@@ -340,7 +338,7 @@ class ConstructorConverter(private val psiClass: PsiClass, private val converter
         //TODO: we can generate it private when secondary constructors are supported by Kotlin
         //val modifiers = Modifiers(listOf(Modifier.PRIVATE)).assignNoPrototype()
         val parameterList = ParameterList(parameters).assignNoPrototype()
-        val constructorSignature = PrimaryConstructorSignature(modifiers, parameterList).assignNoPrototype()
+        val constructorSignature = PrimaryConstructorSignature(Annotations.Empty, modifiers, parameterList).assignNoPrototype()
         val updatedMembers = classBody.members.filter { !fieldsToInitialize.contains(it) }
         return ClassBody(constructorSignature, updatedMembers, classBody.classObjectMembers, updatedFactoryFunctions, classBody.lBrace, classBody.rBrace)
     }

j2k/src/org/jetbrains/jet/j2k/ast/Annotation.kt

@@ -66,3 +66,6 @@ class Annotations(val annotations: List<Annotation>, val newLines: Boolean) : El
         val Empty = Annotations(listOf(), false)
     }
 }
+
+fun Annotations.withBrackets(): Annotations
+        = Annotations(annotations.map { Annotation(it.name, it.arguments, true).assignPrototypesFrom(it) }, newLines).assignPrototypesFrom(this)

j2k/src/org/jetbrains/jet/j2k/ast/Constructors.kt

@@ -37,17 +37,23 @@ class PrimaryConstructor(annotations: Annotations,
     public fun signature(): PrimaryConstructorSignature {
         val noBody = block.isEmpty
         val inheritance = CommentsAndSpacesInheritance(blankLinesBefore = false, commentsAfter = noBody, commentsInside = noBody)
-        return PrimaryConstructorSignature(modifiers, parameterList).assignPrototypesFrom(this, inheritance)
+        return PrimaryConstructorSignature(annotations, modifiers, parameterList).assignPrototypesFrom(this, inheritance)
     }
 }
 
-class PrimaryConstructorSignature(val modifiers: Modifiers, val parameterList: ParameterList) : Element() {
+class PrimaryConstructorSignature(val annotations: Annotations, val modifiers: Modifiers, val parameterList: ParameterList) : Element() {
     override fun generateCode(builder: CodeBuilder) {
         val accessModifier = modifiers.filter { it in ACCESS_MODIFIERS && it != Modifier.PUBLIC }
-        if (accessModifier.isEmpty && parameterList.parameters.isEmpty()) return
+        if (accessModifier.isEmpty && annotations.isEmpty && parameterList.parameters.isEmpty()) return
+
+        if (!annotations.isEmpty) {
+            builder append " " append annotations.withBrackets()
+        }
+
         if (!accessModifier.isEmpty) {
             builder append " " append accessModifier
         }
+
         builder append "(" append parameterList append ")"
     }
 }

j2k/tests/test/org/jetbrains/jet/j2k/test/JavaToKotlinConverterTestGenerated.java

@@ -821,6 +821,11 @@ public class JavaToKotlinConverterTestGenerated extends AbstractJavaToKotlinConv
             doTest("j2k/tests/testData/ast/constructors/chain.java");
         }
         
+        @TestMetadata("constructorAnnotations.java")
+        public void testConstructorAnnotations() throws Exception {
+            doTest("j2k/tests/testData/ast/constructors/constructorAnnotations.java");
+        }
+        
         @TestMetadata("customerBuilder.java")
         public void testCustomerBuilder() throws Exception {
             doTest("j2k/tests/testData/ast/constructors/customerBuilder.java");

j2k/tests/testData/ast/constructors/constructorAnnotations.java

@@ -0,0 +1,29 @@
+import javaApi.Anon5;
+
+class A {
+    private final int a;
+    private final int b;
+
+    @Anon5(10)
+    public A(int a, int b) {
+        this.a = a;
+        this.b = b;
+    }
+
+    @Deprecated // this constructor will not be replaced by default parameter value in primary because of this annotation
+    public A(int a) {
+        this(a, 1);
+    }
+}
+
+class B {
+    @Anon5(11)
+    public B() {
+    }
+}
+
+class C {
+    @Anon5(12)
+    private C() {
+    }
+}

j2k/tests/testData/ast/constructors/constructorAnnotations.kt

@@ -0,0 +1,17 @@
+import javaApi.Anon5
+
+
+deprecated("") // this constructor will not be replaced by default parameter value in primary because of this annotation
+fun A(a: Int): A {
+    return A(a, 1)
+}
+
+class A
+[Anon5(10)]
+(private val a: Int, private val b: Int)
+
+class B [Anon5(11)]
+()
+
+class C [Anon5(12)]
+private()