PW 3.0.123 admin pages timing out in debug mode due to WireCache

[ren]

Upgraded a site from 3.0.98 to 3.0.123 and now all admin pages are timing out. The problem seems to be debug mode in combination with using WireCache for around 3,400 items. Confirmed on a fresh install, but would appreciate if anyone could try replicating before I file an issue...

To replicate, in config.php:

$config->debug = true;
$config->debugTools = array(
	'pages',
	'api',
	'session',
	'modules',
	'hooks',
	'database',
	'db',
	'timers',
	'user',
	'input',
	'cache',
);

Fill the cache with some dummy data:

for ($i = 1; $i < 4000; $i++) {
	$cache->save($i, $i);
}

Then try and view any admin page.

The issue goes away if 'cache' is removed from $config->debugTools , or if the site is downgraded to 3.0.98.

Happens with or without Tracy.

Edited January 18, 2019 by ren

[ren]

Opened an issue https://github.com/processwire/processwire-issues/issues/813