Edit report at http://bugs.php.net/bug.php?id=49625&edit=1
ID: 49625
Comment by: simon at systemparadox dot co dot uk
Reported by: jo at feuersee dot de
Summary: spl_autoload and case sensitivity
Status: Bogus
Type: Bug
Package: SPL related
Operating System: Linux
PHP Version: 5.3.0
Block user comment: N
Private report: N
New Comment:
Why is this bug marked as bogus?
Even if spl_autoload itself isn't fixed, at the very least a version
that does it correctly could be added (although in this case it
seriously could just be fixed by trying the correct case first).
Implementing one in PHP is all very well, but that means that it's
non-standard and likely incompatible with what each programmer might
expect. It's also slower.
Previous Comments:
------------------------------------------------------------------------
[2009-09-23 07:11:47] sjo...@php.net
Trying both lowercased and original case could solve this without
breaking backwards compatibility. However, you could as well supply your
own autoload function defined in PHP to solve this.
------------------------------------------------------------------------
[2009-09-22 19:37:20] jo at feuersee dot de
>The reason here is that is spl_autoload becomes case
>sensitive, it will break scripts which depend on spl_autoload being
>case insensitive.
spl_autoload() was introduced in PHP 5.1.2 which is case sensitive
concerning class names. This implies that if an operation on an unknown
class is done, spl_autoload() is triggered and executed with the case
sensitive name of the class.
Thus we have 4 different possibilities:
1) The class name all lower case, the file containing the class
definition is all lower case (eg. $foo = system::bar(); system.php)
This will work independent wether spl_autoload() is lowercasing or not,
since all is lowercased.
Note that if the class defined in the file system.php is actually named
System it wouldn't have ever worked because the class system is still
not defined, which would trigger an error.
2) The class name all lower case, the file containing the class
definition is uppercased (eg. $foo = system::bar(); System.php)
This wouldn't work anymore on file systems which are case sensitive if
spl_autoload() would skip lowercasing.
Note that this would only have worked if the file system is case
insensitive and the class definition in System.php would define a class
"system".
3) The class name contains upper case letters, the file containing the
class definition is lowercased (eg. $foo = System::bar(); system.php)
This is what currently isn't working at all but would work at least for
case insensitive file systems if lowercasing would be dropped.
Note that if the class defined in the file system.php is actually named
system it wouldn't have ever worked because the class System is still
not defined.
4) The class name contains upper case letters, the file containing the
class definition is uppercased (eg. $foo = System::bar(); System.php)
This is what should (and would) work, but currently doesn't.
Conclusion:
The only problem might be (2):
Class name: sample
Filename: Sample.php
Class definition in Sample.php: class sample { ... }
Note: this does work on case insensitive file systems only.
I really can't see any reason for maintaining the "Worse is better"
principle here, I really doubt that there is much code around relying on
the tolowercase feature/bug of spl_autoload().
As a compromise I propose the following:
1) spl_autoload() additionally tries to find a file _not_ lowercased. 2)
Throw a E_DEPRECATED in case the filename had to be lowercased to
match.
Until then:
I really don't know why this lowercasing thing was introduced into
slp_autoload() to begin with, all it ever did was preventing classes to
be named with upper case letters on file systems which are case
sensitive. In other words: the only compatibility issue is that code
which currently works on platforms like Windows only would suddenly work
on UN*X like platforms too.
Pls confirm if this is the compatibility issue you are talking about.
------------------------------------------------------------------------
[2009-09-22 16:22:22] sjo...@php.net
Thank you for your bug report.
Wontfix means: we agree that there is a bug, but there are reasons not
to fix it. The reason here is that is spl_autoload becomes case
sensitive, it will break scripts which depend on spl_autoload being case
insensitive.
------------------------------------------------------------------------
[2009-09-22 16:01:15] jo at feuersee dot de
Description:
------------
This is basically the same as PHP bug #48129.
Yes, I have read it "won't fix"
My opinion on this is "won't fix" is not an option because it _is_ a bug
and not fixing bugs does not work:
1) It is common practice in OO languages (including PHP) to give classes
case sensitive names. Even the classes of PHP itself are case sensitive
and usually start with capital letters (eg. DateTime, Exception, ...).
PHP related projects like PEAR, Zend Framework etc. do the same.
2) In order to get a proper 1:1 mapping from class name to the file
containing the PHP class definition, projects like PEAR or Zend
Framework use the case sensitive class name, eg. System.php contains the
class System. Again, this is common practice in other OO languages like
C++.
3) What happens when the file system is case sensitive?
See example: the script fails because the PEAR class System will be
looked for in a file named system.php which does not exist because it is
called System.php
The workaround is using SPL_autoload_suxx instead. But look at the code:
there are several compatibility issues (include_path separator : vs. ;),
it does work but is not at all convenient.
4) What would happen if spl_autoload() wouldn't lowercase the class name
when looking for a class definition?
a) Filesystem is case sensitive
It would work!
The spl_autoload() would look for a file called System.php which exists,
thus will be require'd
b) Filesystem is not case sensitive
It would still work!
The spl_autoload() would look for a file called System.php
Because the file system is case insensitive, it would use either
System.php or system.php (or sYSTEM.PHP - you got the point?).
Because on case insentive filesystems both files "System.php" and
"system.php" are not allowed in the same directory, there is _no_ issue
with backward compatibility.
The only circumstances where it would break backwards compatibility
would be on filesystem which is case insensitive but does not allow
capital letters. Any real live examples of such a file system?
Conclusion:
The current specification of spl_autoload() with implicit lowercasing is
excactly wrong. There has been, is and never will be any gain in this
'feature' since the class name itself inside PHP is case sensitive.
Reproduce code:
---------------
<?php
/**
* Demonstration of the current incompatibility
* Make sure you have PEAR inside your PHP include_path
*/
// this should work but doesn't
spl_autoload_register('spl_autoload');
// this does work
//spl_autoload_register('SPL_autoload_suxx');
/**
* Does the same as spl_autoload, but without lowercasing
*/
function SPL_autoload_suxx($name)
{
$rc = FALSE;
$exts = explode(',', spl_autoload_extensions());
$sep = (substr(PHP_OS, 0, 3) == 'Win') ? ';' : ':';
$paths = explode($sep, ini_get('include_path'));
foreach($paths as $path) {
foreach($exts as $ext) {
$file = $path . DIRECTORY_SEPARATOR . $name . $ext;
if(is_readable($file)) {
require_once $file;
$rc = $file;
break;
}
}
}
return $rc;
}
$binaries = array(
'mysql' => System::which('mysql'),
'mysqlbinlog' => System::which('mysqlbinlog'),
'php' => System::which('php')
);
print_r($binaries);
?>
Expected result:
----------------
Array
(
[mysql] => /usr/bin/mysql
[mysqlbinlog] => /usr/bin/mysqlbinlog
[php] => /usr/local/bin/php
)
Actual result:
--------------
PHP Fatal error: Class 'System' not found in
/srv/www/vhosts/www.easy-sew.de/ftpjung/bin/autoload.php on line 38
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Edit this bug report at http://bugs.php.net/bug.php?id=49625&edit=1
