[PHP-BUG] Bug #71236 [NEW]: Second call of spl_autoload_register() does nothing if it has no arguments

From:             php at maisqi dot com
Operating system: Windows and Linux
PHP version:      Irrelevant
Package:          SPL related
Bug Type:         Bug
Bug description:Second call of spl_autoload_register() does nothing if it has no arguments

Description:
------------
spl_autoload_register() with no arguments registers spl_autoload(). But
if we call spl_autoload_register() with a custom function before, it
does nothing.
Nothing in the documentation seems to support this behaviour as valid.

Tested on PHP 5.5 Linux, 5.6 Win64 and 7.01 Win64.

Test script:
---------------
<?php
echo '<pre>';
/**
 * Every one of these code blocks must be run in separated.
 */
// Custom function first; spl_autoload after.
spl_autoload_register(function ($class) {});
spl_autoload_register();
print_r(spl_autoload_functions());	// Prints only one entry.
/*

// Custom function first; spl_autoload after.
spl_autoload_register(function ($class) {});
spl_autoload_register('spl_autoload');
print_r(spl_autoload_functions());	// Prints two entries, as expected.

// spl_autoload first; custom function after.
spl_autoload_register();
spl_autoload_register(function ($class) {});
print_r(spl_autoload_functions());	// Prints two entries, as expected.
*/

Expected result:
----------------
All blocks should print two entries.

Actual result:
--------------
All blocks should print two entries, except the first that only prints
one.

-- 
Edit bug report at https://bugs.php.net/bug.php?id=71236&edit=1
-- 
Try a snapshot (PHP 5.4):   https://bugs.php.net/fix.php?id=71236&r=trysnapshot54
Try a snapshot (PHP 5.5):   https://bugs.php.net/fix.php?id=71236&r=trysnapshot55
Try a snapshot (trunk):     https://bugs.php.net/fix.php?id=71236&r=trysnapshottrunk
Fixed in SVN:               https://bugs.php.net/fix.php?id=71236&r=fixed
Fixed in release:           https://bugs.php.net/fix.php?id=71236&r=alreadyfixed
Need backtrace:             https://bugs.php.net/fix.php?id=71236&r=needtrace
Need Reproduce Script:      https://bugs.php.net/fix.php?id=71236&r=needscript
Try newer version:          https://bugs.php.net/fix.php?id=71236&r=oldversion
Not developer issue:        https://bugs.php.net/fix.php?id=71236&r=support
Expected behavior:          https://bugs.php.net/fix.php?id=71236&r=notwrong
Not enough info:            https://bugs.php.net/fix.php?id=71236&r=notenoughinfo
Submitted twice:            https://bugs.php.net/fix.php?id=71236&r=submittedtwice
register_globals:           https://bugs.php.net/fix.php?id=71236&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=71236&r=php4
Daylight Savings:           https://bugs.php.net/fix.php?id=71236&r=dst
IIS Stability:              https://bugs.php.net/fix.php?id=71236&r=isapi
Install GNU Sed:            https://bugs.php.net/fix.php?id=71236&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=71236&r=float
No Zend Extensions:         https://bugs.php.net/fix.php?id=71236&r=nozend
MySQL Configuration Error:  https://bugs.php.net/fix.php?id=71236&r=mysqlcfg