Copy: Copy entire file if it contains just a selected declaration

idea/src/org/jetbrains/kotlin/idea/refactoring/copy/CopyKotlinDeclarationsHandler.kt

@@ -187,6 +187,8 @@ class CopyKotlinDeclarationsHandler : CopyHandlerDelegateBase() {
         val originalFile = elementsToCopy.first().containingFile as KtFile
         val initialTargetDirectory = defaultTargetDirectory ?: originalFile.containingDirectory ?: return
 
+        val isSingleDeclarationInFile = singleElementToCopy is KtNamedDeclaration && originalFile.declarations.singleOrNull() == singleElementToCopy
+
         val project = initialTargetDirectory.project
 
         val commandName = "Copy Declarations"
@@ -249,16 +251,24 @@ class CopyKotlinDeclarationsHandler : CopyHandlerDelegateBase() {
 
                     val oldToNewElementsMapping = HashMap<PsiElement, PsiElement>()
 
+                    val fileToCopy = when {
+                        singleElementToCopy is KtFile -> singleElementToCopy
+                        isSingleDeclarationInFile -> originalFile
+                        else -> null
+                    }
+
                     val targetFile: KtFile
-                    if (singleElementToCopy is KtFile) {
+                    val copiedDeclaration: KtNamedDeclaration?
+                    if (fileToCopy != null) {
                         targetFile = runWriteAction {
-                            val copiedFile = targetDirectory.copyFileFrom(targetFileName, singleElementToCopy) as KtFile
+                            val copiedFile = targetDirectory.copyFileFrom(targetFileName, fileToCopy) as KtFile
-                            if (singleElementToCopy.packageMatchesDirectory()) {
+                            if (fileToCopy.packageMatchesDirectory()) {
                                 targetDirectory.getPackage()?.qualifiedName?.let { copiedFile.packageFqName = FqName(it) }
                             }
                             performDelayedRefactoringRequests(project)
                             copiedFile
                         }
+                        copiedDeclaration = if (isSingleDeclarationInFile) targetFile.declarations.singleOrNull() as? KtNamedDeclaration else null
                     }
                     else {
                         targetFile = getOrCreateTargetFile(originalFile, targetDirectory, targetFileName, commandName) ?: return@executeCommand
@@ -274,9 +284,10 @@ class CopyKotlinDeclarationsHandler : CopyHandlerDelegateBase() {
 
                             performDelayedRefactoringRequests(project)
                         }
+                        copiedDeclaration = oldToNewElementsMapping.values.filterIsInstance<KtNamedDeclaration>().singleOrNull()
                     }
 
-                    (oldToNewElementsMapping.values.filterIsInstance<KtNamedDeclaration>().singleOrNull())?.let { newDeclaration ->
+                    copiedDeclaration?.let { newDeclaration ->
                         if (newName == newDeclaration.name) return@let
                         val selfReferences = ReferencesSearch.search(newDeclaration, LocalSearchScope(newDeclaration)).findAll()
                         runWriteAction {

idea/testData/refactoring/copy/copySingleClass/after/bar/A.kt

@@ -0,0 +1,7 @@
+package bar
+
+// test
+
+class A
+
+// test2

idea/testData/refactoring/copy/copySingleClass/after/foo/A.kt

@@ -0,0 +1,7 @@
+package foo
+
+// test
+
+class A
+
+// test2

idea/testData/refactoring/copy/copySingleClass/before/foo/A.kt

@@ -0,0 +1,7 @@
+package foo
+
+// test
+
+class <caret>A
+
+// test2

idea/testData/refactoring/copy/copySingleClass/copySingleClass.test

@@ -0,0 +1,4 @@
+{
+  "mainFile": "foo/A.kt",
+  "targetPackage": "bar"
+}

idea/testData/refactoring/copy/copySingleClassWithRename/after/bar/B.kt

@@ -0,0 +1,7 @@
+package bar
+
+// test
+
+class B
+
+// test2

idea/testData/refactoring/copy/copySingleClassWithRename/after/foo/A.kt

@@ -0,0 +1,7 @@
+package foo
+
+// test
+
+class A
+
+// test2

idea/testData/refactoring/copy/copySingleClassWithRename/before/foo/A.kt

@@ -0,0 +1,7 @@
+package foo
+
+// test
+
+class <caret>A
+
+// test2

idea/testData/refactoring/copy/copySingleClassWithRename/copySingleClassWithRename.test

@@ -0,0 +1,5 @@
+{
+  "mainFile": "foo/A.kt",
+  "targetPackage": "bar",
+  "newName": "B"
+}

idea/testData/refactoring/copy/refToImportJavaStaticField/after/foo/test.kt

@@ -5,3 +5,7 @@ import foo.J.JJJ
 fun test() {
     val x = JJJ
 }
+
+fun dummy() {
+
+}

idea/testData/refactoring/copy/refToImportJavaStaticField/before/foo/test.kt

@@ -5,3 +5,7 @@ import foo.J.JJJ
 fun <caret>test() {
     val x = JJJ
 }
+
+fun dummy() {
+
+}

idea/testData/refactoring/copy/refToImportJavaStaticMethod/after/foo/test.kt

@@ -5,3 +5,7 @@ import foo.J.jjj
 fun test() {
     jjj()
 }
+
+fun dummy() {
+
+}

idea/testData/refactoring/copy/refToImportJavaStaticMethod/before/foo/test.kt

@@ -5,3 +5,7 @@ import foo.J.jjj
 fun <caret>test() {
     jjj()
 }
+
+fun dummy() {
+
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/copy/CopyTestGenerated.java

@@ -168,12 +168,24 @@ public class CopyTestGenerated extends AbstractCopyTest {
         doTest(fileName);
     }
 
+    @TestMetadata("copySingleClass/copySingleClass.test")
+    public void testCopySingleClass_CopySingleClass() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/copy/copySingleClass/copySingleClass.test");
+        doTest(fileName);
+    }
+
     @TestMetadata("copySingleClassFile/copySingleClassFile.test")
     public void testCopySingleClassFile_CopySingleClassFile() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/copy/copySingleClassFile/copySingleClassFile.test");
         doTest(fileName);
     }
 
+    @TestMetadata("copySingleClassWithRename/copySingleClassWithRename.test")
+    public void testCopySingleClassWithRename_CopySingleClassWithRename() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/copy/copySingleClassWithRename/copySingleClassWithRename.test");
+        doTest(fileName);
+    }
+
     @TestMetadata("copyTopLevelFunction/copyTopLevelFunction.test")
     public void testCopyTopLevelFunction_CopyTopLevelFunction() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/copy/copyTopLevelFunction/copyTopLevelFunction.test");