Upgrading Legacy to the Latest PHP Version

Your application runs on an old PHP version that is about to go out of support. How to upgrade without breaking the application? You will need the right tools for detecting and fixing those issues, as well as a way to verify that the application is still working correctly. In this presentation, I will share the strategy that I employed when upgrading millions of lines of untested code.

Transcript

1. Upgrading Legacy to the Latest PHP Version PHPDAY | MAY 17, 2024 @afilina@phpc.social | @afilina
2. I Stand With Ukraine "I don't know whether my application works on the latest PHP."
3. I Stand With Ukraine • 4M lines of code • As low as PHP 4 • register_globals • undefined vars • dead libraries (pre-composer) • removed extensions
4. I Stand With Ukraine Anna Filina • Coding since 1997. • PHP, Java, C#, Flash, etc. • Legacy archaeology. • Test automation. • Mentoring. • Filina Consulting.
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7. I Stand With Ukraine • Find compatibility issues. • Fix the issues. • Test the fixes.
8. I Stand With Ukraine PHPCompatibility scanner
9. I Stand With Ukraine ./vendor/bin/phpcs -p . --standard=PHPCompatibility --colors --extensions=php,inc,phtml --runtime-set testVersion 8.3
10. I Stand With Ukraine FILE: /www/src/app/controllers/MyController.php ------------------------------------------------------------------ FOUND 1 ERROR AFFECTING 1 LINE ------------------------------------------------------------------ 166 | ERROR | Using 'break' outside of a loop or switch structure | | is invalid and will throw a fatal error since PHP | | 7.0 ------------------------------------------------------------------
11. I Stand With Ukraine • php.net: docs, release notes, migration guides. • php-legacy-docs.zend.com • phplift.com (WIP) • exakat.readthedocs.io (compatibility rulesets) • Experimentation. • PHP source code.
12. I Stand With Ukraine PHPCompatibility tells us what to fix
13. I Stand With Ukraine $response = '1234567890'; $header = 'Content-length: ' . strlen($response) + 1; echo $header;
14. I Stand With Ukraine 3v4l.org run code in different PHP versions
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18. I Stand With Ukraine $response = '1234567890'; $header = 'Content-length: ' . (strlen($response) + 1); echo $header;
19. I Stand With Ukraine Function each() is deprecated since PHP 7.2; Use a foreach loop instead
20. I Stand With Ukraine while (list($i, $row) = each($result)) foreach ($result as $i => $row)
21. I Stand With Ukraine $key = each($result)['key']; $value = each($result)['value’]; $key = each($result)[0]; $value = each($result)[1];
22. I Stand With Ukraine $row1 = each($result); $row2 = each($result);
23. I Stand With Ukraine else if (list(, $optArg) = each($args))
24. I Stand With Ukraine final class Php56 { public static function each(array &$array) { if (current($array) === false) { return false; } $key = key($array); $value = current($array); next($array); return [ 1 => $value, 'value' => $value, 0 => $key, 'key' => $key, ]; } }
25. I Stand With Ukraine Portable, unit-tested solution wrapped in a class
26. I Stand With Ukraine mcrypt PHP
27. I Stand With Ukraine mcrypt PECL PHP
28. I Stand With Ukraine mcrypt PECL PHP libmcrypt
29. I Stand With Ukraine • Can we keep using libmcrypt? • New mcrypt extension does not behave the same.
30. I Stand With Ukraine PHP openssl
31. I Stand With Ukraine mcrypt.OFB != openssl.OFB
32. I Stand With Ukraine PHP phpseclib/mcrypt_compat
33. I Stand With Ukraine How to test mcrypt upgrade?
34. I Stand With Ukraine encrypted Old app test data New app
35. I Stand With Ukraine public function testCanDecrypt() { //... $decrypted = $security->decrypt($encrypted); self::assertEquals($original, $decrypted); }
36. I Stand With Ukraine mysql_ mysqli_ PDO
37. I Stand With Ukraine • Connection object needs to be available. • Connection object now a mysqli type. • Field metadata represented differently. • Different methods for unbuffered queries.
38. I Stand With Ukraine mysql to mysqli conversion can't be unit-tested.
39. I Stand With Ukraine mysql_connect mysql_query mysql_close mysqli_connect mysqli_query mysqli_close $connection $connection
40. I Stand With Ukraine High-level tests • Integration • Characterization • Manual (not recommended)
41. I Stand With Ukraine Cypress characterization tests
42. I Stand With Ukraine npm install cypress
43. I Stand With Ukraine npx cypress open
44. I Stand With Ukraine Make changes Write tests Execute on legacy & upgrade First test passes on upgrade
45. I Stand With Ukraine As many tests as you need to be confident
46. I Stand With Ukraine • Login: critical + simple • Reservations: critical + complex • Reporting: medium + complex • FAQ: low + simple • PDF: low + complex
47. I Stand With Ukraine Takeaways • Write high-level tests • Discover issues with PHPCompatibility • Research the rest based on failed tests • Consider many solutions (don’t decide too quickly) • Make decisions that can be changed later
48. Questions? PHPDAY | MAY 17, 2024 @afilina@phpc.social | @afilina