Add quickfix for adding documentation

idea/idea-analysis/src/org/jetbrains/kotlin/idea/inspections/IntentionBasedInspection.kt

@@ -122,15 +122,15 @@ abstract class IntentionBasedInspection<TElement : KtElement>(
             editor?.caretModel?.moveToOffset(startElement.textOffset)
             intention.applyTo(startElement as TElement, editor)
         }
-
-        private fun PsiElement.findExistingEditor(): Editor? {
-            val file = containingFile?.virtualFile ?: return null
-            val document = FileDocumentManager.getInstance().getDocument(file) ?: return null
-
-            val editorFactory = EditorFactory.getInstance()
-
-            val editors = editorFactory.getEditors(document)
-            return if (editors.isEmpty()) null else editors[0]
-        }
     }
 }
+
+fun PsiElement.findExistingEditor(): Editor? {
+    val file = containingFile?.virtualFile ?: return null
+    val document = FileDocumentManager.getInstance().getDocument(file) ?: return null
+
+    val editorFactory = EditorFactory.getInstance()
+
+    val editors = editorFactory.getEditors(document)
+    return if (editors.isEmpty()) null else editors[0]
+}

idea/idea-analysis/src/org/jetbrains/kotlin/idea/kdoc/KDocMissingDocumentationInspection.kt

@@ -16,7 +16,13 @@
 
 package org.jetbrains.kotlin.idea.kdoc
 
+import com.intellij.codeInspection.LocalQuickFix
+import com.intellij.codeInspection.ProblemDescriptor
 import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.editor.EditorFactory
+import com.intellij.openapi.fileEditor.FileDocumentManager
+import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
@@ -24,7 +30,15 @@ import org.jetbrains.kotlin.descriptors.MemberDescriptor
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptor
 import org.jetbrains.kotlin.idea.inspections.AbstractKotlinInspection
+import org.jetbrains.kotlin.idea.inspections.findExistingEditor
+import org.jetbrains.kotlin.kdoc.psi.impl.KDocImpl
+import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
+import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.psi.KtModifierListOwner
 import org.jetbrains.kotlin.psi.KtNamedDeclaration
+import org.jetbrains.kotlin.psi.addRemoveModifier.removeModifier
+import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
+import org.jetbrains.kotlin.psi.psiUtil.startOffset
 import org.jetbrains.kotlin.resolve.source.getPsi
 
 class KDocMissingDocumentationInspection(): AbstractKotlinInspection() {
@@ -42,10 +56,24 @@ class KDocMissingDocumentationInspection(): AbstractKotlinInspection() {
                                            (descriptor as? CallableMemberDescriptor)?.overriddenDescriptors
                                                    ?.any { (it.source.getPsi() as? KtNamedDeclaration)?.docComment != null } ?: false
                     if (!hasDocumentation) {
-                        holder.registerProblem(nameIdentifier, "Missing documentation")
+                        holder.registerProblem(nameIdentifier, "Missing documentation", AddDocumentationFix())
                     }
                 }
             }
         }
     }
+
+    class AddDocumentationFix : LocalQuickFix {
+        override fun getName(): String = "Add documentation"
+
+        override fun getFamilyName(): String = name
+
+        override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+            val declaration = descriptor.psiElement.getParentOfType<KtNamedDeclaration>(true)
+                              ?: throw IllegalStateException("Can't find declaration")
+            declaration.addBefore(KDocElementFactory(project).createKDocFromText("/**  */"), declaration.firstChild)
+            val editor = descriptor.psiElement.findExistingEditor()
+            editor?.caretModel?.moveToOffset(declaration.startOffset + 4)
+        }
+    }
 }

idea/testData/quickfix/kdocMissingDocumentation/.inspection

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.kdoc.KDocMissingDocumentationInspection

idea/testData/quickfix/kdocMissingDocumentation/simple.kt

@@ -0,0 +1,4 @@
+// "Add documentation" "true"
+
+class <caret>C {
+}

idea/testData/quickfix/kdocMissingDocumentation/simple.kt.after

@@ -0,0 +1,5 @@
+// "Add documentation" "true"
+
+/** <caret> */
+class C {
+}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -4798,6 +4798,21 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
         }
     }
 
+    @TestMetadata("idea/testData/quickfix/kdocMissingDocumentation")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class KdocMissingDocumentation extends AbstractQuickFixTest {
+        public void testAllFilesPresentInKdocMissingDocumentation() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/kdocMissingDocumentation"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), true);
+        }
+
+        @TestMetadata("simple.kt")
+        public void testSimple() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/kdocMissingDocumentation/simple.kt");
+            doTest(fileName);
+        }
+    }
+
     @TestMetadata("idea/testData/quickfix/libraries")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)