Bug #78101 [Nab]: Icorrect behaviour for substr on Windows

From: Date: Tue, 04 Jun 2019 01:00:35 +0000
Subject: Bug #78101 [Nab]: Icorrect behaviour for substr on Windows
References: 1  Groups: php.bugs 
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Edit report at https://bugs.php.net/bug.php?id=78101&edit=1

 ID:                 78101
 User updated by:    mishamosher at gmail dot com
 Reported by:        mishamosher at gmail dot com
 Summary:            Icorrect behaviour for substr on Windows
 Status:             Not a bug
 Type:               Bug
 Package:            *General Issues
 Operating System:   Windows 10 1903 64-bits
 PHP Version:        7.2.19
 Block user comment: N
 Private report:     N

 New Comment:

Hello subjective@php.net,

Are your results from running the script with PHP as an Apache module?

I've thoroughly tried over and over again, and no matter what, I always get the wrong results.

var_dump reports <<string(3) "/es">>.

I've been able to pin-point the issue to the OPCache extension. If I simply remove
"zend_extension=opcache" from php.ini, everything works as it should.

Please note that I'm experiencing this issue only with PHP 7.2.19 when it is working as an
Apache module.

I can use PHP 7.2.11, 5.6.40, 7.3.6, etc., with OPCache enabled and everything works OK in there.

As a final note, what can I do to 'ring' attention to an existing filed bug? It is about
this one: https://bugs.php.net/bug.php?id=77014
- at least to know if it is a bug or intended behaviour.


Previous Comments:
------------------------------------------------------------------------
[2019-06-03 21:24:05] subjective@php.net

I tested it on Windows using the following script:

var_dump(
  substr("/es", 0, 1)
);
var_dump(
  substr("\xEF\xBB\xBF/es", 0, 1)
);

Output:

string(1) "/"
string(1) "�"


In general try using var_dump() on the source string. It will report the byte length, so you will
notice invisible characters.

------------------------------------------------------------------------
[2019-06-03 20:55:31] mishamosher at gmail dot com

Hello requinix@php.net,

I appreciate your attention into the matter.

I know for sure that there are no multibyte strings or invisible characters in my testing. Functions
strlen, mb_strlen and mb_detect_encoding return 3, 3 and "ASCII" respectively.

In the mantime, I've just finished configuring PHP 7.2.11 and PHP 7.3.6, as Apache modules, and
they both do not exibit this issue with the very same test file and test environment.

The real mistery for me is why specifically PHP 7.2.19 does not want to work as it should. Please
note that the issue presents itself only when I run PHP 7.2.19 as an Apache module. The issue does
not occur when I run PHP via CMD (php.exe -f script.php).

Is there any specific test or debug information that I can provide to further identify the issue?

------------------------------------------------------------------------
[2019-06-03 19:23:35] requinix@php.net

Either you typed an invisible character (copy/pasted a BOM?) or that slash is a Unicode slash made
up of multiple bytes.

If you intend to support multibyte strings and non-ASCII encodings then use mbstring and mb_substr()
instead.

------------------------------------------------------------------------
[2019-06-03 18:48:45] mishamosher at gmail dot com

Description:
------------
I am trying this simple code:

<?php
echo substr("/es", 0, 1);
?>

I expect to see a "/" as a result, but I get "�" instead.

PHP is running in an entirely 64-bit environment.

 - Windows 10 1903
 - PHP 7.2.19 (as an apache module)
 - Apache 2.4.39

Running PHP from the console (php.exe -f script.php) functions properly.

Test script:
---------------
<?php
echo substr("/es", 0, 1);
?>

Expected result:
----------------
"/"

Actual result:
--------------
"�"


------------------------------------------------------------------------



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