Edit report at https://bugs.php.net/bug.php?id=60694&edit=1
ID: 60694
Comment by: phpmpan at mpan dot pl
Reported by: MarkAndrewSlade at gmail dot com
Summary: print() results in bad logic
Status: Open
Type: Bug
Package: Scripting Engine problem
Operating System: CentOS release 5.4 (Final)
PHP Version: 5.3.8
Block user comment: N
Private report: N
New Comment:
Invalid interpretation of the code caused by misleading parenthenses.
1. false && print ('')
-> false && (print (''))
-> false && 1
-> false
2. print('') && false
-> (print (('') && false))
-> (print false)
-> 1
-> true
3. print('') && false && false
-> (print ((('') && false) && false))
-> (print false)
-> 1
-> true
4. (print('') && false) && true
-> ( print (('') && false) ) && true
-> (print false) && true
-> 1 && true
-> true
5. (print('') && false) && false
-> (print (('') && false) && false
-> (print false) && false
-> 1 && false
-> false
I believe that documentation for all language constructs (`echo`, `include`,
`print`, ...) should explicitly discourage use of parenthenses around
arguments. They're very misleading.
Previous Comments:
------------------------------------------------------------------------
[2012-01-10 02:26:21] MarkAndrewSlade at gmail dot com
Description:
------------
Unlike echo, the print construct is allowed inside logic clauses. If it is
reached (not short-circuited), it will cause the rest of that clause to be
true.
Tested with 5.3.8 and PHP 5.3.9RC5-dev, both with default configure.
Test script:
---------------
<?php
echo (false && print('')) ? "Fail\n" : "Pass\n";
echo (print('') && false) ? "Fail\n" : "Pass\n";
echo (print('') && false && false) ? "Fail\n" : "Pass\n";
echo ((print('') && false) && true) ? "Fail\n" : "Pass\n";
echo ((print('') && false) && false) ? "Fail\n" : "Pass\n";
?>
Expected result:
----------------
The word "Pass" five times.
Actual result:
--------------
The middle three fail. The first and last pass, and are included to
demonstrate
the limits of the bug.
------------------------------------------------------------------------
--
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