Do not rewrite imports if namespace is empty

[abn]

This is usefuly when the vendor directory is expected to be added to sys.path.

[pradyunsg]

@abn Thanks for the PR!

I'm not sure I understand the use case here - how is putting a directory on sys.path directly be relevant to putting the packages in the source tree, to avoid bootstrapping issues like the ones pip and setuptools have?

Or is this for a completely separate use case, that you'd like this tool to support?

[abn]

This would be a slightly different use case.

python-poetry/poetry-core#25

I was looking at maintaining the use of the tool, do everything it currently does, but not rewrite the imports explicitly. The idea, discussed in the issue related to the above PR, was to make debundling easier for distribution maintainers by adding the vendor directory into sys.path and maintaining the original import statements. So, in theory, one could drop the vendor directory and poetry would pick up the system packages.

[pradyunsg]

Sounds fair!