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WordPress

_preload_old_requests_classes_and_interfaces( string $to )

Since
6.2.0
Source
wp-admin/includes/update-core.php:1948
Preloads old Requests classes and interfaces.

Description

This function preloads the old Requests code into memory before the upgrade process deletes the files. Why? Requests code is loaded into memory via an autoloader, meaning when a class or interface is needed If a request is in process, Requests could attempt to access code. If the file is not there, a fatal error could occur. If the file was replaced, the new code is not compatible with the old, resulting in a fatal error. Preloading ensures the code is in memory before the code is updated.

Compatibility

WordPress
since 6.2.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$tostring
Path to old WordPress installation.

Performance profile

How much work a call to _preload_old_requests_classes_and_interfaces() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Trivial

Touches nothing outside its own arguments.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
17

Executed per call on PHP 8.5. The body compiles to 52.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
1

1 place in core call this, so the cost is paid more often than your own code shows.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost _preload_old_requests_classes_and_interfaces() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
always17->set_bookmark()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev52178
8.55217817 more instructions than PHP 8.4
8.43511–1782 fewer instructions than PHP 8.3
8.33711–178
8.23711–178
8.13711–178
7.43711–178

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Used by · 1

Source code

function _preload_old_requests_classes_and_interfaces( $to ) {	global $_old_requests_files, $wp_filesystem, $wp_version; 	/*	 * Requests was introduced in WordPress 4.6.	 *	 * Skip preloading if the website was previously using	 * an earlier version of WordPress.	 */	if ( version_compare( $wp_version, '4.6', '<' ) ) {		return;	} 	if ( ! defined( 'REQUESTS_SILENCE_PSR0_DEPRECATIONS' ) ) {		define( 'REQUESTS_SILENCE_PSR0_DEPRECATIONS', true );	} 	foreach ( $_old_requests_files as $name => $file ) {		// Skip files that aren't interfaces or classes.		if ( is_int( $name ) ) {			continue;		} 		// Skip if it's already loaded.		if ( class_exists( $name ) || interface_exists( $name ) ) {			continue;		} 		// Skip if the file is missing.		if ( ! $wp_filesystem->is_file( $to . $file ) ) {			continue;		} 		require_once $to . $file;	}}

Changelog

Introduced in 6.2.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-admin/includes/update-core.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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