PLS doesn't flag error in a relative import if it is found in another root directory

[erictraut]

The analyzer incorrectly accepts relative imports in cases where the path is relative to a root but not to the importing file.

Consider the following case:
Directory structure:
src
|->module
|--->init.py
test.py

PYTHONPATH=src

test.py contains the following code:

from .module import Foo

This import should be flagged as invalid because the path ".module" should be relative to the test.py file. However, the code in PathResolverSnapshot.GetImportsFromRelativePath considers all of the root search directories when it performs its search. It therefore finds an import match when it shouldn't.

I think the problem is in PathResolverSnapshot.RootContains. It doesn't do anything to validate that the specified lastEdge starts in the same location as the root. If the relative path happens to match items within that root, the method returns true. If the relative path is zero length, all roots return true.

A proposed fix is to add the following piece of code to PathResolverSnapshot.RootContains before the while loop:

if (root != sourceEdge.Next.Start) {
    rootEdge = default;
    return false;
}

[AlexanderSher]

The problem isn't related to the multiple roots. With "python.autoComplete.extraPaths": ["path_to_folder/src"] and the following file structure:

├─ package
│  └─ test.py
└─ src
   └─ package
      └─ module
         └─ __init__.py

code from .module import * in test.py is valid.

But, from .module is invalid when test.py is in root, no matter if we have module or not.

[AlexanderSher]

We probably should have an exception for the working directory, cause it can be a top directory of the module.