This was an approach I had picked up during Drupal Con Lille from senior developers: that some people are not necessarily good at programming, but simply know their way around Core. By knowing where everything can be found and what it does, they can quickly and efficiently create solutions for clients. But this proved easier said than done. Core contains a lot of and sometimes complex code, although well documented, it remains a challenge to fathom. As a Core mainstay sat next to me, I seized my opportunity to ask how he had tackled this, how he had gotten to this point.
His answer was clear: by diving deep into the code, making a mind map of his exploration, and taking notes on how these parts related to each other. He gave a concrete example: when he wanted to understand how the renderer in Drupal worked, he started exploring. Step by step, he approached the core of how rendering worked, until he discovered that the renderer contained a bug that prevented anything from being rendered. By continuing to search, he eventually discovered that Core rendered everything through the HTML renderer and thus bypassed the bug. He stressed that a structured approach is essential: have a clear goal when examining the code and gradually work toward it. Along the way, try to understand how the puzzle pieces fit together and eventually see the full picture.
When I expressed my overwhelm about Core code, he provided another valuable insight: "Core reads like a book. "He clarified this by pointing to the coding standards in Core, which ensure that the code is readable and understandable. Well-documented features make it easy for new developers to understand what the code does, unlike some enterprise codebases that are often less accessible.
