Preparing for the next PHP version (5.6)

Preparing for the next
PHP version

Towards PHP 5.5 and 5.6
• Changing version is often a big challenge
• Backward incompatibilities
• New features
• How to spot them ?

Speaker
• Damien Seguy
• CTO at exakat
• Phather of the plush toy
elePHPant
• Will talk on automated
code audit later

PHP linting
• command line : php -l filename.php
• Will only parse the code,
• not execution
• Will spot compilation problems

PHP lint will find
• Short array syntax
• Function subscripting
• break/continue with variables
• Rare other situations
• Code that won’t compile anyway

Where else code will break?
• PHP running has 3 stages
• parsed
• compiled
• executed
Checked with lint
Checked code review
Checked with data and UT

What will change?
• Removed features
• Deprecated features
• Changed features
• New features

Deprecated features
• PHP 5.6
• $HTTP_RAW_POST_DATA
5.6
• Call From Incompatible Context
• iconv and mbstring directives go to default_charset
• PHP 5.5
• /e in preg_replace
• ext/mysql
5.5
• mcrypt arguments

Deprecated features
• Replace it by php://input
• php://input is now reusable
• ext/mysql
• Look for mysql_* functions
• Probably in Db/Adapter
5.6
5.5

Search is your friend
• Grep, or IDE’s search function will help you
• Look for mysql_*

Error_level to E_STRICT
Deprecated: The mysql extension is
deprecated and will be removed in
the future: use mysqli or PDO
instead in /path/to/filename.php on
line 11

/e and charset directives
• preg_replace(‘/ /e’, ‘evaled code’,
$haystack)
• replaced preg_replace_callback(‘/ /‘,
closure, $haystack)
• in php.ini, check for mbstring, iconv and
default_charset
5.5
5.6

Where to look for
• preg_replace
• Search for preg_replace function calls
• defaut_charset
• Search for ini_set, ini_get, ini_get_all,
ini_restore, get_cfg_var
• Seach in php.ini, .htaccess

Incompatible context
$ php53 test.php
Notice: Undefined variable: this in test.php on line 3
A
<?php
class A {
function f() { echo get_class($this); }
}
A::f();
?>
5.6
$ php56 test.php
Strict Standards: Non-static method A::f() should not be called
statically in /Users/famille/Desktop/test.php on line 6
Notice: Undefined variable: this in test.php on line 3
A

Search for situations
• Search for :: operator
• Get the class
• then the method
• then the static keyword
• Needs a automated auditing tool
• Code sniffer, IDE

Strict Standards: Non-static method
A::f() should not be called
statically in test.php on line 6

Changed behavior
• json_decode is stricter
• it was more tolerant before with TRUE or False values
• gmp resources are object
• and not resources
• search for is_resource()
• mcrypt requires valid keys and vectors
• check correct size and vector presence
• pack and unpack
• More compatible with Perl
• Z and a format code must be checked
5.6
5.5

Added structures
• PHP adds
• constants
• functions
• extensions
• traits
• interfaces

Added structures
Functions Classes Constants
5.3 25 18 80
5.4 0 9 78
5.5 113 9 37
5.6 19 0 24
Total 157 36 219

New features
• Fixing
• Modernization
• New feature

empty() upgrade
• No need
anymore to
expressions in a
variable for
empty()!
function myFunction() {
return -2 ;
}
if (empty(myFunction() + 2)) {
echo "This means 0!n";
}
Fatal error: Can't use function return value in write context in test.php on line 6
5.5

SELF::const != self::const
<?php
class object {
const x = 1;
function x() { print SELF::x."n"; }
}
$object = new object();
$object->x();
?>
Fatal error: Class 'SELF' not found in test.php on line 6
5.5

Dereferencing
• Direct access to
element in a string
or an array.
<?php
/// Function dereferencing
echo str_split("123", 1 )[2];
echo "n";
/// Array dereferencing
echo [5, 5, 3][0];
echo "n";
/// String dereferencing
echo 'PHP'[0];
echo "n";
5.5 ?>

Power operator
• Replaces pow()
• Be aware of precedence
echo pow(2, 3);
$a=2;
$a **= 3;
$a = 2 ** 3;
5.6

… Variadic
• replaces
func_get_args()
• Easier to read
function array_power($pow, ...$integers) {
foreach($integers as $i) {
print "$i ^ $pow = ". ($i ** $pow)."n";
}
}
array_power(3, 1, 2, 3, 4, 5);
1 ^ 3 = 1
2 ^ 3 = 8
3 ^ 3 = 27
4 ^ 3 = 64
5 ^ 3 = 125
5.6

Variadic …
• replaces
call_user_func_array
• Easier to read
• Works on functions
• Works with typehint
• Doesn’t work with
references
function array_power($pow, ...$integers) {
foreach($integers as $i) {
print "$i ^ $pow = ". ($i ** $pow)."n";
}
}
array_power(3, ...range(1, 5));
array_power(3, ...[1, 2, 3, 4, 5]);
array_power(3, ...[1, 2, 3], ...[4, 5]);
1 ^ 3 = 1
2 ^ 3 = 8
3 ^ 3 = 27
4 ^ 3 = 64
5 ^ 3 = 125

Generators
function factors($limit) {
$r = array(2);
for ($i = 3; $i <= $limit; $i += 2) {
$r[] = $i;
}
return $r;
}
$prime = 135;
foreach (factors(sqrt($prime)) as $n) {
echo "$n ". ($prime % $n ? ' not ' : '') . " factor}
• $step big => huge
memory usage
5.5

Generators
• New yield keyword
• Save memory from
n down to 1 value
• Good for long or
infinite loops
• Search for range(),
for() or loops
function factors($limit) {
yield 2;
for ($i = 3; $i <= $limit; $i += 2) {
yield $i;
}
}
$prime = 135;
foreach (factors(sqrt($prime)) as $n) {
echo "$n ". ($prime % $n ? ' not ' : '') . " factor}

Finally
• Clean up after
exception or
not
• Clean up even
when return
too early
function x() {
$r = new resource();
try {
$result = $r->do();
}
catch (NetworkException $e) {
throw $e;
}
catch (UnexpectedException $e) {
throw $e;
}
catch (DaylightSavingException $e) {
// just ignore this one
} finally {
unset ($r) ;
}
return $result;
}

Class name resolution
<?php
namespace NameSpace;
class ClassName {}
echo ClassName::class;
echo "n";
?>
• Get the full name of
a class with ::class
5.5

class somePasswordSa_fe {_ debugInfo()
private $user;
private $password;
public function __construct($user, $password) {
$this->user = $user;
$this->password = $password;
}
public function __debugInfo() {
return [
'user' => $this->password,
'password' => '**********',
];
}
}
print_r(new somePasswordSafe('root', 'secret'));
somePasswordSafe Object
(
[user] => secret
[password] => **********
)
5.6

use const / functions
namespace NameSpace {
const FOO = 42;
function f() { echo __FUNCTION__."n"; }
}
namespace {
use const NameSpaceFOO;
use function NameSpacef;
echo FOO."n";
f();
}
• Importing constants
or functions from
another namespace
• Keep things
separated
• Avoid polluting
global namespace
• Avoid static only
classes
5.6

Constant scalar expressions
class Version {
const MAJOR = 2;
const MIDDLE = ONE;
const MINOR = 1;
const FULL = Version::MAJOR.'.'.Version::MIDDLE.'.'.Version::MINOR.'-'.PHP_VERSION;
const SHORT = Version::MAJOR.'.'.Version::MIDDLE;
const COMPACT = Version::MAJOR.Version::MIDDLE.Version::MINOR;
public function f($a = (MAJOR == 2) ? 3 : Version::MINOR ** 3) {
return $a;
}
}
• Code automation
• Won’t accept functioncalls
• Keep it simple
5.6

Foreach supports list
• And any type
<?php
of keys
• Good with
Iterator
classes
• Not possible
with Arrays
class object implements Iterator {
/.../
function key() { return array(1,2); }
function current() { return 3; }
/.../
}
$object = new object();
foreach($object as list($a, $b) = $c) {
print "$a + $b + $c = ".($a + $b + $c)."n";
}
?>
5.5

Context changes
• PHP 5.6
• Windows XP and 2003 dropped
• Support for Zend Optimiser
• PHP 5.5
• phpdbg
• Large File Upload 5.5
5.6

www.slideshare
.net/dseguy
damien.seguy@gmail.com

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