PHP7 is here, and with it several advantages. However, when your enterprise application is almost ten years old, there are plenty of pitfalls and hidden surprises that have to be taken care of. This is a talk about our experiences in migrating to PHP7, the advantages it brings and the problems we had. PHP User Group Munich Meeting - September 28, 2016

1. Version November 2014 November 2015 May 2016
PHP 5.3 14.85% 9.90% 2.43%
PHP 5.4 28.61% 22.09% 7.64%
PHP 5.5 48.87% 50.68% 29.56%
PHP 5.6 7.67% 22.09% 39.67%
PHP 7.0 - 1.17% 20.24%
Source: seld.be

2. MIGRATING TO PHP7
Moving from PHP5.3 to PHP7.0

3. RICHARD PRILLWITZ
PHP and JavaScript developer
Refined Labs GmbH

4. REFINED LABS GMBH
Founded 2007
Munich-based
About 30 employees

5. Centralised analysis of marketing budgets
Cross-Channel-Tracking and Customer Journey
Optimizing marketing budget based on individual
attribution models
Automatically optimise SEM- & RTB-Budgets via Cross-
Channel-Bid Management

7. AGENDA
Why upgrading?
Getting started
Problems and pitfalls
Testing
Advantages
Future development

8. WHY UPGRADE OUR APPLICATION?

9. Mature, monolithic enterprise application
Lots of data to collect, filter and analyze
predates Unit-Testing

10. GETTING STARTED
Switch the PHP-Version on my dev machine
:~$ sudo a2dismod php5 && sudo a2enmod php7.0 && sudo service apache2 restart
Reload the application
PHP Fatal error: Uncaught Error: Call to undefined function mysql_escape_string() in /home/richard/...

11. PROBLEMS AND PITFALLS

12. 1
REMOVED EXTENSION

13. MYSQL
PHP5
$myEscapedString = mysql_escape_string($myString);
PHP7
$myEscapedString = mysqli_real_escape_string($dbLink, $myString);

14. 2
EXTENDED EXCEPTION HANDLING

15. DIVIDE BY ZERO
var_dump(3/0);
var_dump(0/0);
var_dump(0%0);
PHP5
PHP Warning: Division by zero
bool(false)
PHP Warning: Division by zero
bool(false)
PHP Warning: Division by zero
bool(false)
PHP7
PHP Warning: Division by zero
float(INF)
PHP Warning: Division by zero
float(NAN)
PHP Fatal error: Uncaught DivisionByZeroError: Modulo by zero

16. JSON_ENCODE
$inf = 3/0;
$nan = 0/0;
$myArray = array(
$inf,
$nan
);
var_dump(json_encode($myArray));
PHP5
string(13) "[false,false]"
PHP7
bool(false)

17. 3
CODE EVALUATION

18. VARIABLE INTERPOLATION
$obj­>$properties['name']
PHP5
$obj­>{$properties['name']}
PHP7
{$obj­>$properties}['name']

19. 4
SIGNATURE CHANGE

20. SESSION_SET_SAVE_HANDLER
PHP5.3
function emptyFunction(){}
session_set_save_handler(
"emptyFunction",
"emptyFunction",
"emptyFunction",
"emptyFunction",
"emptyFunction",
"emptyFunction"
);
PHP7
function emptyFunction(){return true;}
session_set_save_handler(
"emptyFunction",
"emptyFunction",
"emptyFunction",
"emptyFunction",
"emptyFunction",
"emptyFunction"
);

21. TESTING OUR APPLICATION

22. TESTING SETUP
Testing was scheduled for about two months

24. ADVANTAGES

25. PERFORMANCE

26. FUTURE DEVELOPMENT

27. NULL COALESCING OPERATOR
PHP5
$myVar = isset($_GET['attributeName']) ? $_GET['attributeName'] : 'defaultValue';
PHP7
$myVar = $_GET['attributeName'] ?? 'defaultValue';
$myVar = $_GET['attributeName'] ?? $_GET['fallbackAttributeName'] ?? 'defaultValue';

28. SPACESHIP OPERATOR
PHP5
if ($a == $b) {
return 0;
}
return ($a < $b) ? ­1 : 1;
PHP7
return $a <=> $b;

29. RETURN TYPE DECLARATIONS
function getMyArray() : array {
return $this­>myArray;
}

30. SCALAR TYPE HINTING
function getNumber(int $intNumber) : int {
return $intNumber;
}
var_dump(getNumber(3)); // int(3)
var_dump(getNumber("5")); // int(5)
var_dump(getNumber(2.87)); // int(2)
var_dump(getNumber(false)); // int(0)
var_dump(getNumber(true)); // int(1)
var_dump(getNumber("foo")); // PHP Fatal error

31. CONCLUSION
Upgrading to PHP7 is not that hard
PHP7 might be a huge boost in performance
Cleaner and more stable code
But...
...it will not solve all your problems

32. Questions?