From 2b70d44b57a4ec3b449c70e6deb547415c2623e7 Mon Sep 17 00:00:00 2001
From: Dmitry Stogov <dmitry@zend.com>
Date: Fri, 2 Dec 2016 15:13:55 +0300
Subject: [PATCH] Fixed behavior of failing compound assignments (they
 shouldn't change the source value when exception thrown during type
 converion).

---
 Zend/tests/compound_assign_failure.phpt | 17 +++++++++++++++++
 Zend/zend_operators.c                   | 11 +++++++++++
 2 files changed, 28 insertions(+)

diff --git a/Zend/tests/compound_assign_failure.phpt b/Zend/tests/compound_assign_failure.phpt
index f1afc783a0..f8d863106a 100644
--- a/Zend/tests/compound_assign_failure.phpt
+++ b/Zend/tests/compound_assign_failure.phpt
@@ -1,5 +1,7 @@
 --TEST--
 Behavior of failing compound assignment
+--INI--
+opcache.optimization_level=0
 --FILE--
 <?php
 
@@ -17,8 +19,23 @@ try {
 	$a = 1;
 	$a <<= -1;
 } catch (Error $e) { var_dump($a); }
+
+set_error_handler(function() { throw new Exception; });
+
+try {
+	$a = [];
+	$a .= "foo";
+} catch (Throwable $e) { var_dump($a); }
+
+try {
+	$a = "foo";
+	$a .= [];
+} catch (Throwable $e) { var_dump($a); }
 ?>
 --EXPECT--
 int(1)
 int(1)
 int(1)
+array(0) {
+}
+string(3) "foo"
diff --git a/Zend/zend_operators.c b/Zend/zend_operators.c
index 0d3c8e46e7..96571da53e 100644
--- a/Zend/zend_operators.c
+++ b/Zend/zend_operators.c
@@ -1628,6 +1628,10 @@ ZEND_API int ZEND_FASTCALL concat_function(zval *result, zval *op1, zval *op2) /
 			ZEND_TRY_BINARY_OBJECT_OPERATION(ZEND_CONCAT, concat_function);
 			use_copy1 = zend_make_printable_zval(op1, &op1_copy);
 			if (use_copy1) {
+				if (UNEXPECTED(EG(exception))) {
+					zval_dtor(&op1_copy);
+					return FAILURE;
+				}
 				if (result == op1) {
 					if (UNEXPECTED(op1 == op2)) {
 						op2 = &op1_copy;
@@ -1646,6 +1650,13 @@ ZEND_API int ZEND_FASTCALL concat_function(zval *result, zval *op1, zval *op2) /
 			ZEND_TRY_BINARY_OP2_OBJECT_OPERATION(ZEND_CONCAT);
 			use_copy2 = zend_make_printable_zval(op2, &op2_copy);
 			if (use_copy2) {
+				if (UNEXPECTED(EG(exception))) {
+					if (UNEXPECTED(use_copy1)) {
+						zval_dtor(op1);
+					}
+					zval_dtor(&op2_copy);
+					return FAILURE;
+				}
 				op2 = &op2_copy;
 			}
 		}
-- 
2.50.1