Endless recursion when using + on array in foreach

This reverts commit 84b4020.

Fixes GH-11171

(cherry picked from commit dc20cd9)

NEWS

@@ -6,8 +6,6 @@ PHP                                                                        NEWS
   . Fix inconsistent float negation in constant expressions. (ilutov)
   . Fixed bug GH-8841 (php-cli core dump calling a badly formed function).
     (nielsdos)
-  . Fixed bug GH-10085 (Assertion when adding two arrays with += where the first
-    array is contained in the second). (ilutov)
   . Fixed bug GH-10737 (PHP 8.1.16 segfaults on line 597 of
     sapi/apache2handler/sapi_apache2.c). (nielsdos, ElliotNB)
   . Fixed bug GH-11028 (Heap Buffer Overflow in zval_undefined_cv.). (nielsdos)

Zend/tests/gh11171.phpt

@@ -0,0 +1,15 @@
+--TEST--
+GH-11171: Test
+--FILE--
+<?php
+$all = ['test'];
+foreach ($all as &$item) {
+    $all += [$item];
+}
+var_dump($all);
+?>
+--EXPECT--
+array(1) {
+  [0]=>
+  &string(4) "test"
+}

Zend/zend_operators.c

@@ -965,22 +965,16 @@ static ZEND_COLD zend_never_inline void ZEND_FASTCALL zend_binop_error(const cha
 
 static zend_never_inline void ZEND_FASTCALL add_function_array(zval *result, zval *op1, zval *op2) /* {{{ */
 {
+	if (result == op1 && Z_ARR_P(op1) == Z_ARR_P(op2)) {
+		/* $a += $a */
+		return;
+	}
 	if (result != op1) {
 		ZVAL_ARR(result, zend_array_dup(Z_ARR_P(op1)));
-		zend_hash_merge(Z_ARRVAL_P(result), Z_ARRVAL_P(op2), zval_add_ref, 0);
-	} else if (Z_ARR_P(op1) == Z_ARR_P(op2)) {
-		/* $a += $a */
 	} else {
-		/* We have to duplicate op1 (even with refcount == 1) because it may be an element of op2
-		 * and therefore its reference counter may be increased by zend_hash_merge(). That leads to
-		 * an assertion in _zend_hash_add_or_update_i() that only allows adding elements to hash
-		 * tables with RC1. See GH-10085 and Zend/tests/gh10085*.phpt */
-		zval tmp;
-		ZVAL_ARR(&tmp, zend_array_dup(Z_ARR_P(op1)));
-		zend_hash_merge(Z_ARRVAL(tmp), Z_ARRVAL_P(op2), zval_add_ref, 0);
-		zval_ptr_dtor(result);
-		ZVAL_COPY_VALUE(result, &tmp);
+		SEPARATE_ARRAY(result);
 	}
+	zend_hash_merge(Z_ARRVAL_P(result), Z_ARRVAL_P(op2), zval_add_ref, 0);
 }
 /* }}} */