arrayIterators: Restore index to the previous value after NoSuchElementException has been thrown

Relates to #KT-17453

Author: ilya-g

core/runtime.jvm/src/kotlin/jvm/internal/ArrayIterator.kt

@@ -19,7 +19,7 @@ package kotlin.jvm.internal
 private class ArrayIterator<T>(val array: Array<T>) : Iterator<T> {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun next() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun next() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 public fun <T> iterator(array: Array<T>): Iterator<T> = ArrayIterator(array)

core/runtime.jvm/src/kotlin/jvm/internal/ArrayIterators.kt

@@ -21,49 +21,49 @@ package kotlin.jvm.internal
 private class ArrayByteIterator(private val array: ByteArray) : ByteIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextByte() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextByte() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 private class ArrayCharIterator(private val array: CharArray) : CharIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextChar() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextChar() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 private class ArrayShortIterator(private val array: ShortArray) : ShortIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextShort() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextShort() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 private class ArrayIntIterator(private val array: IntArray) : IntIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextInt() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextInt() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 private class ArrayLongIterator(private val array: LongArray) : LongIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextLong() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextLong() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 private class ArrayFloatIterator(private val array: FloatArray) : FloatIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextFloat() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextFloat() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 private class ArrayDoubleIterator(private val array: DoubleArray) : DoubleIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextDouble() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextDouble() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 private class ArrayBooleanIterator(private val array: BooleanArray) : BooleanIterator() {
     private var index = 0
     override fun hasNext() = index < array.size
-    override fun nextBoolean() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }
+    override fun nextBoolean() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }
 }
 
 public fun iterator(array: ByteArray): ByteIterator = ArrayByteIterator(array)

generators/src/org/jetbrains/kotlin/generators/builtins/arrayIterators.kt

@@ -29,7 +29,7 @@ class GenerateArrayIterators(out: PrintWriter) : BuiltInsSourceGenerator(out) {
             out.println("private class Array${s}Iterator(private val array: ${s}Array) : ${s}Iterator() {")
             out.println("    private var index = 0")
             out.println("    override fun hasNext() = index < array.size")
-            out.println("    override fun next$s() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { throw NoSuchElementException(e.message) }")
+            out.println("    override fun next$s() = try { array[index++] } catch (e: ArrayIndexOutOfBoundsException) { index -= 1; throw NoSuchElementException(e.message) }")
             out.println("}")
             out.println()
         }