Symfony Debug & VarDumper - Your daily Must-Have

https://events.drupal.org/neworleans2016/sessions/symfony-debug-vardumper-your-daily-must-have

Transcript

2. Symfony Debug & VarDumper Nicolas Grekas
3. #DrupalCon @nicolasgrekas
4. #DrupalCon @nicolasgrekas
5. Debugging fluency
6. #DrupalCon @nicolasgrekas ✤ Fixing trivial errors ✤ Fixing wrong behaviors ✤ Starts with understanding what’s going on Debugging & Dumping
7. #DrupalCon @nicolasgrekas ✤ Warnings, Notices, Deprecations ✤ User errors, Recoverable errors ✤ Parse errors, Undefined function/class, Type errors ✤ OOM ✤ etc. Dealing with errors in PHP
8. #DrupalCon @nicolasgrekas ✤ Warnings, Notices, Deprecations ✤ User errors, Recoverable errors ✤ $callback = function ($type, $msg, $file, $line, $ctx) {…}; ✤ error_reporting() & “@” silencing operator set_error_handler($callback);
9. #DrupalCon @nicolasgrekas ✤ Parse errors, Undefined function/class, Type errors ✤ ~OOM ✤ $callback = function () {$e = error_get_last();…}; register_shutdown_function($callback);
10. #DrupalCon @nicolasgrekas ✤ try {…} catch (\Exception $e) {…} ✤ set_exception_handler($callback); ✤ $callback = function ($exception) {…}; Exceptions
11. #DrupalCon @nicolasgrekas ✤ try {…} catch (\Error $e) {…} ✤ set_exception_handler($callback); ✤ $callback = function ($exception) {…}; Error/Throwable since PHP 7!
12. #DrupalCon @nicolasgrekas ✤ Typos ✤ Character case mistakes ✤ Decorate using spl_autoload_functions(); ✤ Add suggestions for typos using levenshtein Class loading issues
13. Errors’ lifecycle
14. #DrupalCon @nicolasgrekas Drupal defaults ✤ Notices/warnings are logged ✤ Uncaught \Exceptions trigger the kernel.exception event ✤ PHP 7 \Errors bubble up to the root of the call stack ✤ Uncaught exceptions and fatal errors are logged by the native PHP handler (depending on your ini settings)
15. #DrupalCon @nicolasgrekas Symfony defaults ✤ Notices/warnings are converted to exceptions ✤ Uncaught \Exceptions trigger the kernel.exception event ✤ PHP 7 \Errors bubble up to the root of the call stack ✤ Uncaught exceptions and fatal errors are reinjected into the kernel and end up triggering the kernel.exception event ✤ All types/levels are logged, even when silenced
16. use Symfony\Component\Debug;
17. #DrupalCon @nicolasgrekas ErrorHandler::register()
18. #DrupalCon @nicolasgrekas ErrorHandler::register() ✤ Converts PHP errors to exceptions ✤ Adds scope (local vars) & stack trace info ✤ Un-silence configured error levels ✤ Turns fatal errors into exceptions
19. #DrupalCon @nicolasgrekas ExceptionHandler::register()
20. #DrupalCon @nicolasgrekas DebugClassLoader::enable() ✤ Stacks compile time errors ✤ Forces unsilencing of parse errors (@include 'foo.php';)
21. use Symfony\Component\VarDumper;
22. #DrupalCon @nicolasgrekas Mission statement ✤ Easy to read HTML or CLI output ✤ Accurate state representation ✤ PHP proof ✤ Extensible and reusable
23. #DrupalCon @nicolasgrekas A simple array
24. #DrupalCon @nicolasgrekas A complex array
25. #DrupalCon @nicolasgrekas A simple object
26. #DrupalCon @nicolasgrekas Internal mechanism – #1 ✤ VarCloner takes any $vars ✤ Turns it into a Data object ✤ Using Caster callables ✤ And enforcing state extraction limits
27. #DrupalCon @nicolasgrekas Internal mechanism – #2 ✤ The resulting Data object ✤ Contains a simple PHP array ✤ That holds full precision ✤ Over the state of the initial $var
28. #DrupalCon @nicolasgrekas Internal mechanism – #3 ✤ A Dumper object (CliDumper/HtmlDumper/YourDumper) ✤ Turns the Data object into a string representation ✤ That is written to a PHP stream or line callback
29. #DrupalCon @nicolasgrekas A complex object
30. #DrupalCon @nicolasgrekas Excerpt of the RedisCaster
31. #DrupalCon @nicolasgrekas Dumping “by hand”
32. Let’s practice
33. #DrupalCon @nicolasgrekas ✤ Then just “dump($var)”! ✤ composer global require symfony/var-dumper ✤ auto_prepend_file=$HOME/.composer/vendor/autoload.php composer require symfony/var-dumper
34. #DrupalCon @nicolasgrekas Demo time
35. #DrupalCon @nicolasgrekas sites/default/settings.local.php ✤ ini_set('display_errors', 0); ✤ Debug\DebugClassLoader::enable(); ✤ Debug\ExceptionHandler::register(); ✤ Debug\ErrorHandler::register();
36. #DrupalCon @nicolasgrekas Demo time
37. #DrupalCon @nicolasgrekas More demo ✤ Debug\ErrorHandler::register() ->setExceptionHandler('dump'); ✤ And an exception subscriber
38. #DrupalCon @nicolasgrekas Using a custom dumper
39. What’s next?
40. #DrupalCon @nicolasgrekas What’s next? ✤ Native Drupal integration? ✤ VarDumper module? ✤ Don’t wait after others!
41. Happy dump()!
42. Merci ! Evaluate this session - http://bit.ly/nola-symfony-debug Thanks!