From a80f65cfd99be1722c3f717154eeff8e88caadc7 Mon Sep 17 00:00:00 2001
From: Ilya Gorbunov <ilya.gorbunov@jetbrains.com>
Date: Tue, 16 Jun 2015 16:41:46 +0300
Subject: [PATCH] =?UTF-8?q?Do=20not=20create=20empty=20list=20when=20rever?=
 =?UTF-8?q?sing=20empty=20collection=20or=20array=20=E2=80=94=20use=20sing?=
 =?UTF-8?q?leton=20empty=20list=20instead.=20#KT-8099=20Fixed?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 libraries/stdlib/src/generated/_Ordering.kt   | 20 +++++++++++++++++++
 .../src/templates/Ordering.kt                 | 10 ++++++++++
 2 files changed, 30 insertions(+)

diff --git a/libraries/stdlib/src/generated/_Ordering.kt b/libraries/stdlib/src/generated/_Ordering.kt
index 1c06521a4ca..e8749f9259a 100644
--- a/libraries/stdlib/src/generated/_Ordering.kt
+++ b/libraries/stdlib/src/generated/_Ordering.kt
@@ -14,6 +14,8 @@ import java.util.Collections // TODO: it's temporary while we have java.util.Col
  * Returns a list with elements in reversed order.
  */
 public fun <T> Array<out T>.reverse(): List<T> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -23,6 +25,8 @@ public fun <T> Array<out T>.reverse(): List<T> {
  * Returns a list with elements in reversed order.
  */
 public fun BooleanArray.reverse(): List<Boolean> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -32,6 +36,8 @@ public fun BooleanArray.reverse(): List<Boolean> {
  * Returns a list with elements in reversed order.
  */
 public fun ByteArray.reverse(): List<Byte> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -41,6 +47,8 @@ public fun ByteArray.reverse(): List<Byte> {
  * Returns a list with elements in reversed order.
  */
 public fun CharArray.reverse(): List<Char> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -50,6 +58,8 @@ public fun CharArray.reverse(): List<Char> {
  * Returns a list with elements in reversed order.
  */
 public fun DoubleArray.reverse(): List<Double> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -59,6 +69,8 @@ public fun DoubleArray.reverse(): List<Double> {
  * Returns a list with elements in reversed order.
  */
 public fun FloatArray.reverse(): List<Float> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -68,6 +80,8 @@ public fun FloatArray.reverse(): List<Float> {
  * Returns a list with elements in reversed order.
  */
 public fun IntArray.reverse(): List<Int> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -77,6 +91,8 @@ public fun IntArray.reverse(): List<Int> {
  * Returns a list with elements in reversed order.
  */
 public fun LongArray.reverse(): List<Long> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -86,6 +102,8 @@ public fun LongArray.reverse(): List<Long> {
  * Returns a list with elements in reversed order.
  */
 public fun ShortArray.reverse(): List<Short> {
+    if (isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
@@ -95,6 +113,8 @@ public fun ShortArray.reverse(): List<Short> {
  * Returns a list with elements in reversed order.
  */
 public fun <T> Iterable<T>.reverse(): List<T> {
+    if (this is Collection<*> && isEmpty())
+        return emptyList()
     val list = toArrayList()
     Collections.reverse(list)
     return list
diff --git a/libraries/tools/kotlin-stdlib-gen/src/templates/Ordering.kt b/libraries/tools/kotlin-stdlib-gen/src/templates/Ordering.kt
index 02206b18a89..c81826bfc14 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/templates/Ordering.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/templates/Ordering.kt
@@ -10,6 +10,16 @@ fun ordering(): List<GenericFunction> {
         returns { "List<T>" }
         body {
             """
+            if (this is Collection<*> && isEmpty()) return emptyList()
+            val list = toArrayList()
+            Collections.reverse(list)
+            return list
+            """
+        }
+
+        body(ArraysOfObjects, ArraysOfPrimitives) {
+            """
+            if (isEmpty()) return emptyList()
             val list = toArrayList()
             Collections.reverse(list)
             return list