[PHP-BUG] Bug #74509 [NEW]: array_shift($foo) throws "null given" instead of "Undefined variable"

From:             pov at fingerprint dot fr
Operating system: 
PHP version:      5.6.30
Package:          PHP Language Specification
Bug Type:         Bug
Bug description:array_shift($foo) throws "null given" instead of "Undefined variable"

Description:
------------
When applying array_shift on a non-existing variable, a warning about
array_shift is emitted (array_shift() expects parameter 1 to be array,
null given) instead of a notice on the non-existing variable.

Tested on all the  following packaged versions :
7.0.17-2+deb.sury.org~trusty+1
7.1.3-2+deb.sury.org~trusty+1
5.5.38-4+deb.sury.org~trusty+1
5.6.30-7+deb.sury.org~trusty+1


-- Additional tests
This bug probably applies on other functions as well.
Some tests gives interesting results (I note NUV = Notice : Undefined
variable - ok -, WNG = Warning : null given - which shouldn't be)  :

array_shift($foo)             WNG
array_slice($foo)                     NUV
array_unshift($foo, 1)        WNG 
array_unshift($foo, $bar)             NUV bar (logically, should be NUV
$foo first)
array_pop($foo)               WNG
array_sum($foo)                       NUV
empty($foo)                   returns true
htmlentities($foo)                    NUV


Test script:
---------------
error_reporting(E_ALL | E_NOTICE);
ini_set('display_errors', true);

echo '$foo = '; echo $foo; echo "\n";
echo 'array_shift($foo) = '; echo array_shift($foo); echo "\n";
exit;


Expected result:
----------------
$foo =	
	Notice: Undefined variable: foo in index.php on line 4

array_shift($foo) =
	Notice: Undefined variable: foo in index.php on line 4

Actual result:
--------------
$foo =	
	Notice: Undefined variable: foo in index.php on line 4

array_shift($foo) =
	Warning: array_shift() expects parameter 1 to be array, null given in
index.php on line 5


-- 
Edit bug report at https://bugs.php.net/bug.php?id=74509&edit=1
-- 
Try a snapshot (PHP 5.4):   https://bugs.php.net/fix.php?id=74509&r=trysnapshot54
Try a snapshot (PHP 5.5):   https://bugs.php.net/fix.php?id=74509&r=trysnapshot55
Try a snapshot (trunk):     https://bugs.php.net/fix.php?id=74509&r=trysnapshottrunk
Fixed in SVN:               https://bugs.php.net/fix.php?id=74509&r=fixed
Fixed in release:           https://bugs.php.net/fix.php?id=74509&r=alreadyfixed
Need backtrace:             https://bugs.php.net/fix.php?id=74509&r=needtrace
Need Reproduce Script:      https://bugs.php.net/fix.php?id=74509&r=needscript
Try newer version:          https://bugs.php.net/fix.php?id=74509&r=oldversion
Not developer issue:        https://bugs.php.net/fix.php?id=74509&r=support
Expected behavior:          https://bugs.php.net/fix.php?id=74509&r=notwrong
Not enough info:            https://bugs.php.net/fix.php?id=74509&r=notenoughinfo
Submitted twice:            https://bugs.php.net/fix.php?id=74509&r=submittedtwice
register_globals:           https://bugs.php.net/fix.php?id=74509&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=74509&r=php4
Daylight Savings:           https://bugs.php.net/fix.php?id=74509&r=dst
IIS Stability:              https://bugs.php.net/fix.php?id=74509&r=isapi
Install GNU Sed:            https://bugs.php.net/fix.php?id=74509&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=74509&r=float
No Zend Extensions:         https://bugs.php.net/fix.php?id=74509&r=nozend
MySQL Configuration Error:  https://bugs.php.net/fix.php?id=74509&r=mysqlcfg