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Although most existing PHP 5 code should work without changes, you should pay attention to the following backward incompatible changes:
<?php
print 10 % 0;
/* Warning: Division by zero in filename on line n */
?>
<?php
class foo {}
$foo = new foo;
print $foo;
/* Catchable fatal error: Object of class foo could
not be converted to string in filename on line n */
?>
<?php
class foo {
public function __toString() {
throw new Exception;
}
}
try {
print new foo;
/* Fatal error: Method foo::__toString() must
not throw an exception in filename on line n */
} catch(Exception $e) {}
?>
<?php
abstract class foo {
abstract static function bar();
/* Strict Standards: Static function foo::bar()
should not be abstract in filename on line n */
}
?>
<?php
/* when allow_url_include is OFF (default) */
include "data:;base64,PD9waHAgcGhwaW5mbygpOz8+";
/* Warning: include(): URL file-access is disabled
in the server configuration in filename on line n */
?>
str_pad has been modified as well, to enforce UPPERCASE sensitivity on the pad_type declaration.
Optional argument pad_type can be STR_PAD_RIGHT, STR_PAD_LEFT, or STR_PAD_BOTH. If pad_type is not specified it is assumed to be STR_PAD_RIGHT.
If entered as:
$foo = 10;
$wrong = str_pad($foo, 4,'0',str_pad_left);
print "wrong is '$wrong'<br>";
$right = str_pad($foo,4,'0',STR_PAD_LEFT);
print "right is '$right'<br>";
results:
wrong is ' '
right is ' 10'
If the sole reason for having "abstract static methods" is to force the implementation of such a method in a child, consider using an interface for them. The abstract class implements the interface, and a child class extends the base class and defines the "abstract static methods".
<?php
interface I
{
static public function f();
}
abstract class C implements I
{
// more/other methods go here
}
class D extends C
{
static public function f()
{
echo 'I am f().';
}
}
?>
If any of your code relies on includes of URLS à la allow_url_fopen, be aware that a new directive (allow_url_include) has been added, and that it defaults to Off.
$string="12345";
$rightstring1=substr($string,-3);
$rightstring2=substr($string,-8);
echo "Result1: ".$rightstring1."<BR>";
echo "Result2: ".$rightstring2."<BR>";
PHP5.1.x:
Result1: 345
Result2: 12345
PHP5.2.x
Result1: 345
Result2: <Empty>
Between PHP 5.2.3 and 5.2.4 another backward incompatible change was introduced: parent classes now can not access private properties of child classes with get_object_vars(). See the following example:
class Bar {
public function dumpBar() {
var_dump(get_object_vars($this));
}
}
class Foo extends Bar {
public $public = 'public';
protected $protected = 'protected';
private $private = 'private';
public function dump() {
var_dump(get_object_vars($this));
}
}
$foo = new Foo();
$foo->dump();
$foo->dumpBar();
The result with PHP < 5.2.4:
E:\php\tests>php get_object_vars.php
array(3) {
["public"] => string(6) "public"
["protected"] => string(9) "protected"
["private"] => string(7) "private"
}
array(3) {
["public"] => string(6) "public"
["protected"] => string(9) "protected"
["private"] => string(7) "private"
}
And the result with PHP >= 5.2.4:
E:\php-5.2.4-Win32>php ../php/tests/get_object_vars.php
array(3) {
["public"] => string(6) "public"
["protected"] => string(9) "protected"
["private"] => string(7) "private"
}
array(2) {
["public"] => string(6) "public"
["protected"] => string(9) "protected"
}
As you can see the private property is missing now when dumped from the parent class Bar.
It should be noted that if you provide a __toString method, you can cast the object to a string and use it as an array key (PHP 5.2.x).
e.g. $array[ (string)$myObject ] = 'foobar';
This is an alternative to using spl_object_hash.
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