The why and how of moving to PHP 5.5/5.6

The Why and How of moving to PHP 5.5/5.6

Who am I ?
Wim Godden (@wimgtr)
Founder of Cu.be Solutions (http://cu.be)
Open Source developer since 1997
Developer of OpenX, PHPCompatibility, PHPConsistent, ...
Speaker at Open Source conferences

Why vs How
Part 1 : why upgrade ?
Bad reasons :
It's cool to have the latest version
Annoy sysadmins
Oh cool, a new toy !
Part 2 : how to upgrade ?
The nightmare of compatibility
The joy of automation
No miracles here !

Show of hands
3 / 4
5.0
5.1
5.2
5.3
5.4
5.5
5.6
6.0
7.0

The numbers
W3Techs (http://w3techs.com/technologies/details/pl-php/all/all)
Now Nov 2013 Aug 2013 May 2013
PHP 4 : 1.8% 2.7% 2.9% 2.7%
PHP 5 : 98.2% 97.3% 97.1% 97.3%
5.0 : < 0.1% 0.1% 0.1% 0.1%
5.1 : 1.2% 2.0% 2.2% 2.6%
5.2 : 19.2% 37.6% 40.2% 43.5%
5.3 : 45.5% 52.0% 51.7% 49.7%
5.4 : 26.9% 7.9% 5.7% 4.1%
5.5 : 6.3% 0.5% 0.1 % < 0.1%
5.6 : 0.5% < 0.1%
5.7 : < 0.1%
5.27 : < 0.1%

5.3 quick recap
Namespaces ()
Late static binding
Closures
Better garbage collection
Goto
Mysqlnd
Performance gain

5.4 quick recap
Short array syntax
Function array dereferencing
Traits
Built-in webserver
SessionHandler
File upload extension
Binary notation
register_globals and magic_quotes_gpc removed :-)
Safe mode removed :-)

5.3 – people are not even using it !
19.2% still on PHP 5.2
No :
Symfony 2
Zend Framework 2
Other frameworks that need namespaces
Problematic for developers

PHP 5.5/5.6 – what's changed ?
New features
Performance and memory usage
Improved consistency
Some things removed

New things – Generators (5.5)
Simple way of implementing iterators
Simply put : foreach over a function
Say what ?

Generators - example
<?php
function returnAsciiTable($start, $end) {
for ($i = $start; $i <= $end; $i++) {
yield $i => chr($i);
}
}
foreach (returnAsciiTable(97, 122) as $key => $value) {
echo $key . " - " . $value . "n";
}
Output :
97 - a
98 - b
99 - c
100 - d
101 - e
102 - f
103 - g
104 - h
105 - i
106 - j
107 - k
108 - l
109 - m
110 - n
111 - o
112 - p
113 - q
114 - r
115 - s
116 - t
117 - u
118 - v
119 - w
120 - x
121 - y
122 - z

Finally : finally (5.5)
Exception handling
Until now : try {} catch() {}
Now :
<?php
try {
doSomething();
} catch (Exception $e) {
echo 'Caught exception: ', $e->getMessage(), "n";
} finally {
echo "We're always going here !";
}

Beware : finally + return
<?php
function footest()
{
try {
return 1;
} catch (Exception $e) {
return 2;
} finally {
return 10;
}
}
echo footest();
Will return 10 !

Password hashing (5.5)
To create :
$hash = password_hash($password, PASSWORD_DEFAULT);
To verify :
password_verify($password, $hash);
Currently only supports Blowfish
Also has password_needs_rehash() → check if hash was strong enough

Zend Optimizer+ (5.5)
Name in PHP 5.5 : OPcache
Opcode cache (like APC, Xcache, ...)
APC users : no userland (variable) caching in OPcache
→ Use APCu

Variadic functions
function sumNumbers($base, ...$params)
{
foreach ($params as $param) {
$base += $param;
}
return $base;
}
sumNumbers(5); // returns 5
sumNumbers(5, 2); // returns 7
sumNumbers(5, 2, 3); // returns 10

Argument unpacking
function add($a, $b, $c) {
return $a + $b + $c;
}
$params = array(2, 3);
echo add(5, ...$params); // returns 10

Other changes in 5.6
json_decode() strictness : true, false, null values
Constant expressions :
const ONE = 1;
const TWO = ONE * 2;
Exponent operator (**)
printf("2 ** 4 == %dn", 2 ** 4);
→ Output = 2 ** 4 == 16
use function and use const
Default charset is now UTF-8 → set in ini default_charset
__debuginfo() magic method for use with var_dump()
SSL/TLS security improvements (peer certificate verification,
TLS renegotiation attacks, …)
phpdbg : interactive debugger

Removed features in PHP 5.5
php_logo_guid()
php_egg_logo_guid()
php_real_logo_guid()
zend_logo_guid()
Windows XP and 2003 support

Removed features in PHP 5.6
$HTTP_RAW_POST_DATA and ini setting
always_populate_raw_post_data
iconv and mbstring encoding settings → default_charset in ini

Performance and memory usage from 5.3 to 5.6
Performance : 10 – 30%
How ?
Core optimizations
New internal caches (functions, constants, …)
Better (un)serialization
Inlining often-used code paths
…
Reduced memory usage : up to 50% !
Big impact on large frameworks
Even bigger impact on codebases such as Drupal

So...
Should you upgrade today ?

Upgrade : yes / no
Yes No
Using removed extensions x
Using removed functions x
Need extra performance / reduced memory x
Really need new feature x
Want to use recent framework x
No unit tests x
No package available (.rpm, .deb, ...) x

Postponing upgrades
End-Of-Life
In the past : we'll see
Now : minor release + 2 = out → EOL
5.5 = OUT → 5.3 = EOL
5.6 = OUT → 5.4 = EOL
Critical security patches : 1 year
No bugfixes
Framework support
Developer motivation

So you want to upgrade...
Option 1 : run your unit tests
Option 2 : visit each page (good luck !) + check error_log
Or : record visits, then replay log on test environment
Option 3 : automated static analysis

Unit tests on different PHP versions
Vagrant boxes
Integrate into your CI
Use Travis CI (http://travis-ci.org)

Why make it so hard ? A best-case scenario...
Development environment : 5.6
Production environment : 5.6
All is well, right ?
End 2015 : PHP 7 arrives
How can you test compatibility ?
→ Set up your test environment today
→ Even for new projects

Back in 2010...
PHP Architect @ Belgian Railways
8 years of legacy code
40+ different developers
40+ projects
Challenge :
migrate all projects from
PHP 5.1.x (on Solaris)
to
PHP 5.3.x (on Linux)

The idea
Automate it
How ? → Use the CI environment
Which tool ? → PHP_CodeSniffer

PHP_CodeSniffer
PEAR package (pear install PHP_CodeSniffer)
Detect coding standard violations
Supports multiple standards
Static analysis tool
→ Runs without executing code
→ Splits code in tokens
Ex. : T_OPEN_CURLY_BRACKET
T_FALSE
T_SEMICOLON

PHP_CodeSniffer
Let's see what it looks like

PHPCompatibility
New PHP_CodeSniffer standard
Only purpose : find compatibility issues
Detects :
Deprecated functions
Deprecated extensions
Deprecated php.ini settings and ini_set() calls
Prohibited function names, class names, …
…
Works for PHP 5.0 and above

PHPCompatibility – making it work
Via Composer : wimg/php-compatibility
From Github :
Download :
http://github.com/wimg/PHPCompatibility
Install in <pear_dir>/PHP/CodeSniffer/Standards
Run :
phpcs --standard=PHPCompatibility <path>

PHPCompatibility
Let's see what it looks like

Important notes
Large directories → can be slow !
Use --extensions=php,phtml
No point scanning .js files
Static analysis
Doesn't run code
Can not detect every single incompatibility
Provides filename and line number

The result
Zend Framework 1.7 app
PHP 5.2 : working fine
PHP 5.3 : fail !
function goto()

Some common apps – phpBB (latest)
FILE: /usr/src/phpBB3/adm/index.php
--------------------------------------------------------------------------------
FOUND 0 ERROR(S) AND 2 WARNING(S) AFFECTING 1 LINE(S)
--------------------------------------------------------------------------------
48 | WARNING | INI directive 'safe_mode' is deprecated in PHP 5.3 and forbidden in PHP 5.4.
48 | WARNING | INI directive 'safe_mode' is deprecated in PHP 5.3 and forbidden in PHP 5.4.
--------------------------------------------------------------------------------

Common apps - MediaWiki
FILE: /usr/src/mediawiki-1.19.8/includes/GlobalFunctions.php
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
2705 | WARNING | The use of function dl is discouraged in PHP version 5.3 and
| | discouraged in PHP version 5.4 and discouraged in PHP version
| | 5.5
--------------------------------------------------------------------------------

Common apps – Wordpress (latest)
FILE: /usr/src/wordpress/wp-admin/includes/class-pclzip.php
--------------------------------------------------------------------------------
FOUND 2 ERROR(S) AFFECTING 2 LINE(S)
--------------------------------------------------------------------------------
5340 | ERROR | The use of function set_magic_quotes_runtime is discouraged in
| | PHP version 5.3 and forbidden in PHP version 5.4 and forbidden
| | in PHP version 5.5
5371 | ERROR | The use of function set_magic_quotes_runtime is discouraged in
| | PHP version 5.3 and forbidden in PHP version 5.4 and forbidden
| | in PHP version 5.5
--------------------------------------------------------------------------------
FILE: /usr/src/wordpress/wp-includes/SimplePie/Item.php
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
125 | WARNING | INI directive 'zend.ze1_compatibility_mode' is deprecated in
| | PHP 5.3 and forbidden in PHP 5.4.
--------------------------------------------------------------------------------
FILE: /usr/src/wordpress/wp-includes/wp-db.php
--------------------------------------------------------------------------------
FOUND 16 ERROR(S) AFFECTING 16 LINE(S)
--------------------------------------------------------------------------------
641 | ERROR | Extension 'mysql_' is deprecated since PHP 5.5 - use mysqli
| | instead.
646 | ERROR | Extension 'mysql_' is deprecated since PHP 5.5 - use mysqli
| | instead.

Conclusion
No 100% detection
But : 95% automation = lots of time saved !
First : PHPCompatibility on local machine
Then : use your CI/test environment and run unit tests
Start upgrading !

We're hiring !
Looking for a challenge ?
Want to do more than just code all day ?
→ Come visit our booth !
We've got chocolate ;-)

Thanks !
Please rate my talk at
http://joind.in/13113

The why and how of moving to PHP 5.5/5.6

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