TYPO3 Core

The core ErrorHandler registeres the error handler in construct.
Now, because it implements LoggerAwareInterface, GeneralUtility::makeInstance will try to create a logger after the object (ErrorHandler) has been constructed. That means the error handler is active, while the logger is being created.

Now, when an exception during logger creation happens, the incomplete ErrorHandler is invoked.
This then causes an exception like:

Exception initially reported on Slack by Franz Holzinger with TYPO3 v9.5.24: https://typo3.slack.com/archives/C025BQLFA/p1610482539284400

( ! ) Fatal error: Uncaught TYPO3\CMS\Core\Cache\Exception\NoSuchCacheException: A cache with identifier "assets" does not exist. in /[…]/htdocs/typo3/sysext/core/Classes/Cache/CacheManager.php on line 138
( ! ) TYPO3\CMS\Core\Cache\Exception\NoSuchCacheException: A cache with identifier "assets" does not exist. in /[…]/htdocs/typo3/sysext/core/Classes/Cache/CacheManager.php on line 138
Call Stack
#    Time    Memory    Function    Location
1    0.0000    397120    {main}( )    .../htdocs/index.php:0
2    0.0001    397440    {closure:/[…]/index.php:21-25}( )    .../index.php:25
3    0.0019    516832    TYPO3\CMS\Core\Core\Bootstrap::init( )    .../index.php:24
4    0.0029    648224    TYPO3\CMS\Core\Core\Bootstrap::initializeErrorHandling( )    .../Bootstrap.php:105
5    0.0029    648224    TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance( )    .../Bootstrap.php:705
6    0.0031    651184    TYPO3\CMS\Core\Log\LogManager->getLogger( )    .../GeneralUtility.php:3695
7    0.0031    651376    TYPO3\CMS\Core\Log\LogManager->setWritersForLogger( )    .../LogManager.php:103
8    0.0031    651752    TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance( )    .../LogManager.php:145
9    0.0033    654248    TYPO3\CMS\Core\Log\Writer\FileWriter->__construct( )    .../GeneralUtility.php:3689
10    0.0033    654376    TYPO3\CMS\Core\Log\Writer\FileWriter->setLogFile( )    .../FileWriter.php:82
11    0.0033    654376    TYPO3\CMS\Core\Log\Writer\FileWriter->openLogFile( )    .../FileWriter.php:123
12    0.0034    654752    fopen ( )    .../FileWriter.php:194
13    0.0034    656024    TYPO3\CMS\Core\Error\ErrorHandler->handleError( )    .../FileWriter.php:194
14    0.0035    666992    TYPO3\CMS\Core\TimeTracker\TimeTracker->setTSlogMessage( )    .../ErrorHandler.php:156
15    0.0036    667048    TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance( )    .../TimeTracker.php:219
16    0.0036    668224    TYPO3\CMS\Core\Imaging\IconFactory->__construct( )    .../GeneralUtility.php:3689
17    0.0036    668224    TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance( )    .../IconFactory.php:65
18    0.0036    670704    TYPO3\CMS\Core\Imaging\IconRegistry->__construct( )    .../GeneralUtility.php:3689
19    0.0036    670704    TYPO3\CMS\Core\Imaging\IconRegistry->initialize( )    .../IconRegistry.php:494
20    0.0037    670704    TYPO3\CMS\Core\Imaging\IconRegistry->getCachedBackendIcons( )    .../IconRegistry.php:514
21    0.0037    737544    TYPO3\CMS\Core\Cache\CacheManager->getCache( )    .../IconRegistry.php:540

The exception can be reproduced with an invalid logger configuration like:

$GLOBALS['TYPO3_CONF_VARS']['LOG'] = [
   'writerConfiguration' => [
       \TYPO3\CMS\Core\Log\LogLevel::DEBUG => null,
       \TYPO3\CMS\Core\Log\LogLevel::WARNING => [
           \TYPO3\CMS\Core\Log\Writer\SyslogWriter::class => [],
       ]       
   ]   
];