gsutil rsync and dot-named directory in a bucket

We sync local directory with a bucket using gsutil rsync:
gsutil -m rsync -d -r "gs://${GCS_BUCKET}/plugins" "${base_dir}/plugins"

Recently we had a problem - a file was updated in the bucket but in the local directory we still saw an old version.
We discovered that it was because of a dot-named directory in bucket.
So we had files like:
`plugins/plugins/myfile.py`
`plugins/./plugins/myfile.py`
and after they are copied to linux system they actually point to the same path (so one overrode each other)

Is there anything that could be done? Eg warn a user, or even escape this directory (so both files are copied).

Start by reproducing the reported `gsutil -m rsync -d -r` command with bucket objects containing both `plugins/plugins/myfile.py` and `plugins/./plugins/myfile.py`. Trace how rsync maps object names to local paths, then define and test whether the finished behavior should warn about collisions or preserve both objects without overwriting.

Written by the indexing model from the issue text.