Merge branch 'PHP-8.5'

* PHP-8.5:
  Fix GH-23576: array_keys() on an empty array returns a non-zero next index (#23577)

Author: LamentXU123

NEWS

@@ -91,6 +91,8 @@ PHP                                                                        NEWS
     INT_MAX instead of truncating it. (marc-mabe)
   . Fixed GH-23338 (fsockopen()/pfsockopen() ValueError reported wrong
     argument number for $timeout). (lacatoire)
+  . Fixed bug GH-23576 (Next index for array returned from array_keys() is
+    wrong). (Lazizbek Ergashev)
 
 - SimpleXML:
   . Fixed writing to a dimension of the object returned by attributes() not

ext/standard/array.c

@@ -4406,7 +4406,7 @@ PHP_FUNCTION(array_keys)
 
 	/* Base case: empty input */
 	if (!elem_count) {
-		RETURN_COPY(input);
+		RETURN_EMPTY_ARRAY();
 	}
 
 	/* Initialize return array */

ext/standard/tests/array/gh23576.phpt

@@ -0,0 +1,58 @@
+--TEST--
+GH-23576 (Next index for array returned from array_keys() is wrong)
+--FILE--
+<?php
+$a = [123 => 123];
+unset($a[123]);
+
+$b = array_keys($a);
+$b[] = 42;
+var_dump($b);
+
+$c = array_keys($a, 123);
+$c[] = 42;
+var_dump($c);
+
+$d = array_keys($a, 123, true);
+$d[] = 42;
+var_dump($d);
+
+$e = [];
+
+$f = array_keys($e);
+$f[] = 42;
+var_dump($f);
+
+$g = array_keys($e, 123);
+$g[] = 42;
+var_dump($g);
+
+$h = array_keys($e, 123, true);
+$h[] = 42;
+var_dump($h);
+?>
+--EXPECT--
+array(1) {
+  [0]=>
+  int(42)
+}
+array(1) {
+  [0]=>
+  int(42)
+}
+array(1) {
+  [0]=>
+  int(42)
+}
+array(1) {
+  [0]=>
+  int(42)
+}
+array(1) {
+  [0]=>
+  int(42)
+}
+array(1) {
+  [0]=>
+  int(42)
+}