The Dirty Dozen
Kuba Werłos
Software House Innovative Technologies
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I am having trouble understanding this code.
Let's take a look.
Do you see this function? It calls these 13 other functions and has roughly 1000 lines of commented out code in it.
Ah yes, that is the Job Security Design Pattern in action!
Hundred responsibilities principle
the more the merrier
knows very much or does very much
| knows very much | ⟶ | LOC, properties, methods |
| does very much | ⟶ | cyclomatic complexity |
Hundred responsibilities principle
| LOC | CC | ||
|---|---|---|---|
1. | giggsey/libphonenumber-for-php/geocoding/data/en/61.php | 42 571 | 1 |
2. | Mpdf\Mpdf | 27 208 | 7 007 |
3. | TCPDF | 24 578 | 4 379 |
4. | voku\helper\UTF8 | 14 013 | 1 426 |
5. | TYPO3\CMS\Core\DataHandling\DataHandler | 9 586 | 1 457 |
6. | PhpOffice\PhpSpreadsheet\Reader\Xls | 7 947 | 1 011 |
7. | ScssPhp\ScssPhp\Compiler | 7 709 | 1 197 |
8. | WordPress/wp-includes/functions.php | 7 403 | 737 |
Untestability
Profits of not having tests:
- not doing work no one pays for
- no problems with failing build on Jenkins
- increase need for manual testing
- more thrilling changes to the code
- make it harder to change the code without worrying that anything will get broken
- deprive us from having documentation for what the code is actually meant to do
Untestability
open/closed principle
A module should be open for modification.
A module should be closed for extension.
Redefine the functionality
reinventing the wheel
re-implementing (limited) PHP functions
prefer implementing custom solutions over using open source library
overriding methods
Really big interfaces
big ⟶ complicated
complicated ⟶ advanced
advanced ⟶ smart
Really big interfaces
| Methods | ||
|---|---|---|
1. | Carbon\CarbonInterface | 348 |
2. | Magento\Sales\Api\Data\OrderInterface | 274 |
3. | Illuminate\Support\Enumerable | 112 |
4. | Drupal\Core\Form\FormStateInterface | 91 |
5. | Knp\Menu\ItemInterface | 58 |
6. | Doctrine\ORM\Query\TreeWalker | 50 |
7. | Zend\Barcode\Object\ObjectInterface | 47 |
8. | Symfony\Component\Form\FormInterface | 35 |
You should rely on others
Extend third party libraries directly
class InvoicePdf extends FPDF
{
}Use third party libraries directly
new Symfony\Component\Process\Process(/* ... */);| Hundred responsibilities principle |
| Untestability |
| Redefine the functionality |
| Really big interfaces |
| You should rely on others |
Bus factor
Bus factor
Bus factor
Bus factor
Bus factor
The number of team members who, if run over by a bus, would put the project in jeopardy.
The bigger the number is, more people are inreprecable in the procject.
Our goal is to descrease the bus factor.
Early Optimization
Lack of optimization is the root of all evil.
It is not difficult to know what will be the bottleneck.
Prefer efficiency over simplicity.
Try to cache everything you can.
Inheritance over composition
Magento\Backend\Block\System\Store\Edit\Form\Storeextends Magento\Backend\Block\System\Store\Edit\AbstractFormextends Magento\Backend\Block\Widget\Form\Genericextends Magento\Backend\Block\Widget\Formextends Magento\Backend\Block\Widgetextends Magento\Backend\Block\Templateextends Magento\Framework\View\Element\Templateextends Magento\Framework\View\Element\AbstractBlockextends Magento\Framework\DataObjectInheritance over composition
WET
We Enjoy Typing
