Propagate import dependencies to components

[oxisto]

After finally extensively using the components system, I noticed that while we create import dependencies of translation units and packages across different components (e.g., file a.py in application uses the package os in stdlib component), we store only this information in the individual components. The list is a sorted list of translation units (for example for the symbol resolver) in ascending order of least-dependencies. While this is useful inside a component to resolve them in the correct order, this does not help us when resolving across components.

For example, if we have the following structure (from above):

• application component
  • a.py imports os (which can be found in stdlib)
  • b.py imports a (of application)
  • c.py imports nothing
• stdlib component
  • os.py imports nothing

We would then have a sorted list of units ["c.py", "a.py", "b.py"] for application and ["os.py"] for stdlib. But the order of components is currently not influenced by the information. We can be lucky that we parse stdlib before the application (or not).

Instead, if we would consolidate this information across all components, we would end up with ["os.py", "c.py", "a.py", "b.py"] or ["c.py", "os.py", "a.py", "b.py"] which would provide a better picture.

An even better approach is that, we would need just the information that stdlib needs to be parsed before application. This would allows us to keep the processing of components still separate but do it in the correct order.