Adjustment of auto-import behavior for project-internal imports

[smackesey]

A symbol can be defined in one module and re-exported from several others. When importing a symbol from an external typed library, pylance's behavior is, according to pyright dev @erictraut:

If the same name is exported from multiple modules, the auto-import logic in pyright and pylance prefer the shortest module path. Only the shortest path is listed in the completion list, and the longer paths are de-duped.

However, this is not the behavior for internal project-internal imports. AFAICT, for project-internal imports, resolution is to the module that defines the symbol, i.e. usually the longest exporting module path is preferred. This can be undesirable on large projects where you have big submodules that you want to provide an "internal public" interface for-- e.g. if you have a large submodule project.foo, you might want project-internal code to import only from project.foo itself, rather than project.foo.* submodules.

I'd like to suggest that project-internal auto-imports instead resolve to the shortest non-ancestor module that exposes a symbol. So:

### project/foo/__init__.py
# redundant alias is necessary to expose `BAR` as public for `project.foo`
from .bar import BAR as BAR

### project/foo/bar.py
BAR = "BAR"

### project/baz.py
# "|" is the cursor
BA|  # should offer import "from project.foo import BAR" instead of "from project.foo.bar import BAZ"

[debonte]

@heejaechang

[r3m0t]

Did you try defining __all__ in __init__.py, as that's the usual way to specify what is 'exported' from a module

[smackesey]

@r3m0t __all__ actually does not does not define a module's public interface (I used to think it did too), it can just be used to make symbols that otherwise would be private public. The full rules are here: https://github.com/microsoft/pyright/blob/main/docs/typed-libraries.md#library-interface