Changeset 62524

Timestamp:

06/18/2026 05:49:04 PM (3 months ago)

Author:

dmsnell

Message:

Performance: avoid over-allocation in wp_is_numeric_array()

When a trace of allocations revealed that wp_is_numeric_array()
accounted for a significant fraction of the allocations in a page
render, it was observed that the function eagerly allocates and copies
array keys and then filters them when all it wants to know is whether a
single key in the array meets a condition.

In this patch the array_filter( array_keys() ) invocation is replaced
with early-aborting iteration to avoid the memory allocation and
copying.

This patch was prepared as part of WCEU 2026 Contributor Day.

Developed in: ​https://github.com/WordPress/wordpress-develop/pull/12100
Discussed in: https://core.trac.wordpress.org/ticket/65467

Follow-up to [34927].

Props dmsnell, westonruter, yusufmudagal.
Fixes #65467.

Location:

trunk

Files:

• src/wp-includes/functions.php (modified) (1 diff)
• tests/phpunit/tests/functions/wpIsNumericArray.php (modified) (3 diffs)

trunk/src/wp-includes/functions.php

@@ -5291 +5291 @@
  * Determines if the variable is a numeric-indexed array.
  *
+ * Note! This answers a different question than {@see array_is_list()} and is
+ *       more flexible to handle situations where some numeric array indices
+ *       have been removed. A numeric-indexed array is only a “list” when the
+ *       array keys form a contiguous range from zero to the highest key.
+ *
+ * Example:
+ *
+ *     true  === wp_is_numeric_array( array( 1, 2, 3, 4 ) );
+ *     false === wp_is_numeric_array( array( 'name' => 'WordPress' ) );
+ *
+ *     // All-numeric keys vs. list.
+ *     $above_two   = array_filter( array( 1, 2, 8, 9 ), fn ( $v ) => $v > 2 );
+ *     $above_two === array( '2' => 8, '3' => 9 );
+ *     true       === wp_is_numeric_array( $above_two );
+ *     false      === array_is_list( $above_two );
+ *
  * @since 4.4.0
  *
  * @param mixed $data Variable to check.
  * @return bool Whether the variable is a list.
- */
-function wp_is_numeric_array( $data ) {
+ *
+ * @phpstan-assert-if-true array<int, mixed> $data
+ */
+function wp_is_numeric_array( $data ): bool {
         if ( ! is_array( $data ) ) {
                 return false;
         }
 
-        $keys        = array_keys( $data );
-        $string_keys = array_filter( $keys, 'is_string' );
-
-        return count( $string_keys ) === 0;
+        foreach ( $data as $key => $value ) {
+                if ( is_string( $key ) ) {
+                        return false;
+                }
+        }
+
+        return true;
 }
 

trunk/tests/phpunit/tests/functions/wpIsNumericArray.php

@@ -27 +27 @@
         public function data_wp_is_numeric_array() {
                 return array(
-                        'no index'             => array(
+                        'no index'                             => array(
                                 'test_array' => array( 'www', 'eee' ),
                                 'expected'   => true,
                         ),
-                        'text index'           => array(
+                        'text index'                           => array(
                                 'test_array' => array( 'www' => 'eee' ),
                                 'expected'   => false,
                         ),
-                        'numeric index'        => array(
+                        'numeric index'                        => array(
                                 'test_array' => array( 99 => 'eee' ),
                                 'expected'   => true,
                         ),
-                        '- numeric index'      => array(
+                        'filtered list (missing numeric keys)' => array(
+                                'test_array' => array_filter(
+                                        array( 1, 12, 13, 15, 16, 17, 20 ),
+                                        fn ( $v ) => 0 === $v % 2
+                                ),
+                                'expected'   => true,
+                        ),
+                        '- numeric index'                      => array(
                                 'test_array' => array( -11 => 'eee' ),
                                 'expected'   => true,
                         ),
-                        'numeric string index' => array(
+                        'numeric string index'                 => array(
                                 'test_array' => array( '11' => 'eee' ),
                                 'expected'   => true,
                         ),
-                        'nested number index'  => array(
+                        'nested number index'                  => array(
                                 'test_array' => array(
                                         'next' => array(
@@ -55 +62 @@
                                 'expected'   => false,
                         ),
-                        'nested string index'  => array(
+                        'nested string index'                  => array(
                                 'test_array' => array(
                                         '11' => array(
@@ -63 +70 @@
                                 'expected'   => true,
                         ),
-                        'not an array'         => array(
+                        'not an array'                         => array(
                                 'test_array' => null,
                                 'expected'   => false,