PHP-Setting:docref_root breaks getCompiledRoutes

[pesc]

Symfony version(s) affected: 4.3, 4.4

Description
When the PHP docref_root is set, comparsion (===) doesn't match anymore:

symfony/src/Symfony/Component/Routing/Matcher/Dumper/CompiledUrlMatcherDumper.php

Line 99 in b2d6c10

if (1 < $chunkLimit && $this->signalingException === $e) {

The docref_root set's an URL to a manual and prints it out for exceptions, like this -> in my example to https://secure.php.net/manual/en/:

preg_match() [<a href='https://secure.php.net/manual/en/function.preg-match.php'>function.preg-match.php</a>]: Compilation failed: regular expression is too large at offset 61332

Main problem is that the strpos doesn't return any results:

symfony/src/Symfony/Component/Routing/Matcher/Dumper/CompiledUrlMatcherDumper.php

Line 352 in b2d6c10

set_error_handler(function ($type, $message) { throw 0 === strpos($message, $this->signalingException->getMessage()) ? $this->signalingException : new \ErrorException($message); });

<?php
$mystring = "preg_match() [<a href='https://secure.php.net/manual/en/function.preg-match.php'>function.preg-match.php</a>]: Compilation failed: regular expression is too large at offset 61332";
$findme   = 'preg_match(): Compilation failed: regular expression is too large';
$pos = strpos($mystring, $findme);

// Note our use of ===.  Simply == would not work as expected
// because the position of 'a' was the 0th (first) character.
if ($pos === false) {
    echo "The string '$findme' was not found in the string '$mystring'";
} else {
    echo "The string '$findme' was found in the string '$mystring'";
    echo " and exists at position $pos";
}
?>

The string 'preg_match(): Compilation failed: regular expression is too large' was not found in the string 'preg_match() [<a href='https://secure.php.net/manual/en/function.preg-match.php'>function.preg-match.php</a>]: Compilation failed: regular expression is too large at offset 61332'

How to reproduce
set docref_root to https://secure.php.net/manual/en/ in your php.ini/user.ini....

Possible Solution
unset docref_root to https://secure.php.net/manual/en/ in your php.ini/user.ini....