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alexandre-dauboisiluuu1994
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Fix phpGH-16649: Avoid UAF when using array_splice
Closes phpGH-19399
1 parent 2b415e4 commit c8774f9

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‎NEWS‎

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@@ -6,6 +6,9 @@ PHP NEWS
66
. Fixed bug GH-19245 (Success error message on TLS stream accept failure).
77
(Jakub Zelenka)
88

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- Standard:
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. Fixed bug GH-16649 (UAF during array_splice). (alexandre-daubois)
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912
28 Aug 2025, PHP 8.3.25
1013

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- Core:

‎ext/standard/array.c‎

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@@ -3214,6 +3214,9 @@ static void php_splice(HashTable *in_hash, zend_long offset, zend_long length, H
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zval *entry; /* Hash entry */
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uint32_t iter_pos = zend_hash_iterators_lower_pos(in_hash, 0);
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GC_ADDREF(in_hash);
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HT_ALLOW_COW_VIOLATION(in_hash); /* Will be reset when setting the flags for in_hash */
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/* Get number of entries in the input hash */
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num_in = zend_hash_num_elements(in_hash);
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@@ -3372,6 +3375,15 @@ static void php_splice(HashTable *in_hash, zend_long offset, zend_long length, H
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HT_SET_ITERATORS_COUNT(&out_hash, HT_ITERATORS_COUNT(in_hash));
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HT_SET_ITERATORS_COUNT(in_hash, 0);
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in_hash->pDestructor = NULL;
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if (UNEXPECTED(GC_DELREF(in_hash) == 0)) {
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/* Array was completely deallocated during the operation */
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zend_array_destroy(in_hash);
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zend_hash_destroy(&out_hash);
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zend_throw_error(NULL, "Array was modified during array_splice operation");
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return;
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}
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zend_hash_destroy(in_hash);
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HT_FLAGS(in_hash) = HT_FLAGS(&out_hash);

‎ext/standard/tests/array/gh16649/array_splice_normal_destructor.phpt‎

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--TEST--
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GH-16649: array_splice with normal destructor should work fine
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--FILE--
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<?php
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class C {
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function __destruct() {
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echo "Destructor called\n";
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}
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}
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$arr = ["1", new C, "2"];
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array_splice($arr, 1, 2);
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var_dump($arr);
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?>
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--EXPECT--
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Destructor called
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array(1) {
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[0]=>
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string(1) "1"
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}

‎ext/standard/tests/array/gh16649/array_splice_uaf_add_elements.phpt‎

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@@ -0,0 +1,22 @@
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--TEST--
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GH-16649: array_splice UAF when destructor adds elements to array
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--FILE--
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<?php
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class C {
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function __destruct() {
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global $arr;
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$arr[] = 0;
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}
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}
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$arr = ["1", new C, "2"];
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try {
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array_splice($arr, 1, 2);
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echo "ERROR: Should have thrown exception\n";
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} catch (Error $e) {
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echo "Exception caught: " . $e->getMessage() . "\n";
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}
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?>
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--EXPECT--
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Exception caught: Array was modified during array_splice operation

‎ext/standard/tests/array/gh16649/array_splice_uaf_array_deallocated.phpt‎

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--TEST--
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GH-16649: array_splice UAF when array is released entirely
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--FILE--
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<?php
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class C {
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function __destruct() {
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global $arr;
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$arr = null;
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}
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}
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$arr = ["1", new C, "2"];
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try {
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array_splice($arr, 1, 2);
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echo "ERROR: Should have thrown exception\n";
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} catch (Error $e) {
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echo "Exception caught: " . $e->getMessage() . "\n";
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}
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?>
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--EXPECT--
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Exception caught: Array was modified during array_splice operation

‎ext/standard/tests/array/gh16649/array_splice_uaf_complex_modification.phpt‎

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--TEST--
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GH-16649: array_splice UAF with complex array modification
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--FILE--
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<?php
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class ComplexModifier {
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function __destruct() {
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global $arr;
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// complex modification that causes cow
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unset($arr[0]);
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$arr["new_key"] = "new_value";
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$arr[100] = "another_value";
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}
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}
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$arr = ["first", new ComplexModifier, "last"];
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try {
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array_splice($arr, 1, 1, ["replacement"]);
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echo "ERROR: Should have thrown exception\n";
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} catch (Error $e) {
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echo "Exception caught: " . $e->getMessage() . "\n";
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}
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?>
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--EXPECT--
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Exception caught: Array was modified during array_splice operation

‎ext/standard/tests/array/gh16649/array_splice_uaf_multiple_destructors.phpt‎

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--TEST--
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GH-16649: array_splice UAF with multiple destructors
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--FILE--
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<?php
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class MultiDestructor {
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public $id;
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function __construct($id) {
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$this->id = $id;
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}
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function __destruct() {
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global $arr;
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echo "Destructor {$this->id} called\n";
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if ($this->id == 2) {
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$arr = null;
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}
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}
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}
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$arr = ["start", new MultiDestructor(1), new MultiDestructor(2), "end"];
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try {
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array_splice($arr, 1, 2);
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echo "ERROR: Should have thrown exception\n";
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} catch (Error $e) {
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echo "Exception caught: " . $e->getMessage() . "\n";
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}
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?>
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--EXPECT--
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Destructor 1 called
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Destructor 2 called
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Exception caught: Array was modified during array_splice operation

‎ext/standard/tests/array/gh16649/array_splice_uaf_original_case.phpt‎

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--TEST--
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GH-16649: array_splice UAF with destructor modifying array (original case)
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--FILE--
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<?php
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function resize_arr() {
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global $arr;
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for ($i = 0; $i < 10; $i++) {
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$arr[$i] = $i;
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}
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}
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class C {
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function __destruct() {
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resize_arr();
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return "3";
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}
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}
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$arr = ["a" => "1", "3" => new C, "2" => "2"];
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try {
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array_splice($arr, 1, 2);
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echo "ERROR: Should have thrown exception\n";
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} catch (Error $e) {
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echo "Exception caught: " . $e->getMessage() . "\n";
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}
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?>
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--EXPECT--
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Exception caught: Array was modified during array_splice operation

‎ext/standard/tests/array/gh16649/array_splice_uaf_packed_to_hash.phpt‎

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@@ -0,0 +1,23 @@
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--TEST--
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GH-16649: array_splice UAF when array is converted from packed to hash
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--FILE--
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<?php
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class C {
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function __destruct() {
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global $arr;
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// array is converted from packed to hash
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$arr["str"] = 0;
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}
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}
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$arr = ["1", new C, "2"];
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try {
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array_splice($arr, 1, 2);
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echo "ERROR: Should have thrown exception\n";
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} catch (Error $e) {
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echo "Exception caught: " . $e->getMessage() . "\n";
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}
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?>
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--EXPECT--
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Exception caught: Array was modified during array_splice operation

‎ext/standard/tests/array/gh16649/array_splice_with_replacement.phpt‎

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@@ -0,0 +1,23 @@
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--TEST--
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GH-16649: array_splice with replacement array when destructor modifies array
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--FILE--
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<?php
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class C {
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function __destruct() {
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global $arr;
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$arr["modified"] = "by_destructor";
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}
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}
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$arr = ["a", new C, "b"];
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$replacement = ["replacement1", "replacement2"];
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try {
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array_splice($arr, 1, 1, $replacement);
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echo "ERROR: Should have thrown exception\n";
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} catch (Error $e) {
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echo "Exception caught: " . $e->getMessage() . "\n";
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}
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?>
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--EXPECT--
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Exception caught: Array was modified during array_splice operation

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