When we first think about debugging, we usually don't realize that there are different types of debugging.

Metadata debugging is needed to ensure that the behavior of BitBake's tasks is aligned with our goals, and to identify the culprit when it's not. In this case, we use several log files generated by BitBake in the host in order to help trace the execution path of the involved task. As a consequence of a wrong behavior, a file may not be copied or a feature may not be enabled.

On the other hand, the debugging of runtime code is more natural for us as it is essentially the same as what we do during the normal development cycle of an application, a library, or a kernel. Depending on the kind of issue we are after, the right tool to help may vary from a debugger to code instrumentation (for example, adding debug prints).

In this chapter, we detail metadata debugging as it is the essence of the Yocto Project and supports us during the development and use of Poky.