Description:
------------
$_SERVER disappeared from our admin phpinfo page, after a bit of poking I figured 
out a middleware we're using takes a reference to $_SERVER.

It only reads, doesn't write to it at all - but it breaks phpinfo.

This can be seen in my given example code where simply:

$foo =& $_SERVER;

breaks phpinfo's variable output


Test script:
---------------
<?php

echo "---- Expected Output ----\n\n";

\phpinfo(INFO_VARIABLES);

echo "\n\n---- Actual Broken Output ----\n\n";

$foo =& $_SERVER;

\phpinfo(INFO_VARIABLES);

echo "\n\n---- Proof that \$_SERVER isn't broken ----\n\n";

print_r($_SERVER);


Expected result:
----------------
(truncated to relevant output)

phpinfo()

PHP Variables

Variable => Value
$_SERVER['TMPDIR'] => /var/folders/dr/cpm01_51333c1px2yzc8qr9xq1kth0/T/
$_SERVER['__CF_USER_TEXT_ENCODING'] => 0x6E196A00:0x0:0x0
$_SERVER['HOME'] => /Users/jdonat
$_SERVER['SHELL'] => /bin/zsh
$_SERVER['Apple_PubSub_Socket_Render'] => /private/tmp/com.apple.launchd.d1nNRxAouL/Render
$_SERVER['SSH_AUTH_SOCK'] => /private/tmp/com.apple.launchd.7DMDsXS1qP/Listeners
$_SERVER['PATH'] => /usr/bin:/bin:/usr/sbin:/sbin
$_SERVER['LOGNAME'] => jdonat
$_SERVER['DISPLAY'] => /private/tmp/com.apple.launchd.DHo7IG8khp/org.macosforge.xquartz:0
$_SERVER['XPC_SERVICE_NAME'] => com.electron.standard-otter.146872
$_SERVER['USER'] => jdonat
$_SERVER['XPC_FLAGS'] => 0x0
$_SERVER['PHP_SELF'] => -
$_SERVER['SCRIPT_NAME'] => -
$_SERVER['SCRIPT_FILENAME'] => 
$_SERVER['PATH_TRANSLATED'] => 
$_SERVER['DOCUMENT_ROOT'] => 
$_SERVER['REQUEST_TIME_FLOAT'] => 1617038447.9799
$_SERVER['REQUEST_TIME'] => 1617038447
$_SERVER['argv'] => Array
(
    [0] => -
)

$_SERVER['argc'] => 1

Actual result:
--------------
(truncated to relevant output)

phpinfo()

PHP Variables

Variable => Value