Avoid mutating state and do not rely on side effects for proper function

So #KT-17740 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/MakeOverriddenMemberOpenFix.kt

@@ -35,50 +35,58 @@ import org.jetbrains.kotlin.psi.psiUtil.createSmartPointer
 import org.jetbrains.kotlin.psi.psiUtil.getNonStrictParentOfType
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
-import java.util.*
 
+private typealias DeclPtr = SmartPsiElementPointer<KtCallableDeclaration>
 class MakeOverriddenMemberOpenFix(declaration: KtDeclaration) : KotlinQuickFixAction<KtDeclaration>(declaration) {
-    private val overriddenNonOverridableMembers = ArrayList<SmartPsiElementPointer<KtCallableDeclaration>>()
-    private val containingDeclarationsNames = ArrayList<String>()
 
-    override fun isAvailable(project: Project, editor: Editor?, file: PsiFile): Boolean {
-        val element = element ?: return false
+    private val myQuickFixInfo: QuickFixInfo by lazy {
+        computeState()
+    }
 
-        if (!super.isAvailable(project, editor, file) || file !is KtFile) {
-            return false
-        }
+    private val containingDeclarationsNames
+        get() = myQuickFixInfo.declNames
 
-        // When running single test 'isAvailable()' is invoked multiple times, so we need to clear lists.
-        overriddenNonOverridableMembers.clear()
-        containingDeclarationsNames.clear()
+    private val overriddenNonOverridableMembers
+        get() = myQuickFixInfo.declarations
 
-        val descriptor = element.resolveToDescriptorIfAny(BodyResolveMode.FULL) as? CallableMemberDescriptor ?: return false
+    private fun computeState(): QuickFixInfo {
+        val element = element ?: return QUICKFIX_UNAVAILABLE
+        val overriddenNonOverridableMembers = mutableListOf<DeclPtr>()
+        val containingDeclarationsNames = mutableListOf<String>()
+        val descriptor = element.resolveToDescriptorIfAny(BodyResolveMode.FULL) as? CallableMemberDescriptor ?: return QUICKFIX_UNAVAILABLE
 
         for (overriddenDescriptor in getAllDeclaredNonOverridableOverriddenDescriptors(descriptor)) {
             assert(overriddenDescriptor.kind == DECLARATION) { "Can only be applied to declarations." }
             val overriddenMember = DescriptorToSourceUtils.descriptorToDeclaration(overriddenDescriptor)
             if (overriddenMember == null || !overriddenMember.canRefactor() || overriddenMember !is KtCallableDeclaration ||
                 overriddenMember.modifierList?.hasModifier(OPEN_KEYWORD) == true) {
-                return false
+                return QUICKFIX_UNAVAILABLE
             }
             val containingDeclarationName = overriddenDescriptor.containingDeclaration.name.asString()
             overriddenNonOverridableMembers.add(overriddenMember.createSmartPointer())
             containingDeclarationsNames.add(containingDeclarationName)
         }
-        return overriddenNonOverridableMembers.size > 0
+        return QuickFixInfo(overriddenNonOverridableMembers, containingDeclarationsNames)
+    }
+
+    override fun isAvailable(project: Project, editor: Editor?, file: PsiFile): Boolean {
+
+        if (!super.isAvailable(project, editor, file) || file !is KtFile) {
+            return false
+        }
+
+        return overriddenNonOverridableMembers.isNotEmpty()
     }
 
     override fun getText(): String {
         val element = element ?: return ""
-
         if (overriddenNonOverridableMembers.size == 1) {
             val name = containingDeclarationsNames[0] + "." + element.name
             return "Make $name $OPEN_KEYWORD"
         }
-
-        Collections.sort(containingDeclarationsNames)
-        val declarations = containingDeclarationsNames.subList(0, containingDeclarationsNames.size - 1).joinToString(", ") + " and " +
-                           containingDeclarationsNames.last()
+        val sortedDeclarationNames = containingDeclarationsNames.sorted()
+        val declarations = sortedDeclarationNames.subList(0, sortedDeclarationNames.size - 1).joinToString(", ") + " and " +
+                           sortedDeclarationNames.last()
         return "Make '${element.name}' in $declarations open"
     }
 
@@ -91,6 +99,9 @@ class MakeOverriddenMemberOpenFix(declaration: KtDeclaration) : KotlinQuickFixAc
     }
 
     companion object : KotlinSingleIntentionActionFactory() {
+        private data class QuickFixInfo(val declarations: List<DeclPtr>, val declNames: List<String>)
+
+        private val QUICKFIX_UNAVAILABLE = QuickFixInfo(emptyList(), emptyList())
 
         private fun getAllDeclaredNonOverridableOverriddenDescriptors(
                 callableMemberDescriptor: CallableMemberDescriptor): Collection<CallableMemberDescriptor> {
@@ -104,7 +115,8 @@ class MakeOverriddenMemberOpenFix(declaration: KtDeclaration) : KotlinQuickFixAc
                     FAKE_OVERRIDE, DELEGATION ->
                         result.addAll(getAllDeclaredNonOverridableOverriddenDescriptors(overriddenDescriptor))
 
-                    SYNTHESIZED -> {} /* do nothing */
+                    SYNTHESIZED -> {
+                    } /* do nothing */
 
                     else -> throw UnsupportedOperationException("Unexpected callable kind ${overriddenDescriptor.kind}")
                 }