[3-alpine] shutil.copytree fail to copy a tree with a broken symbolic link

When trying to use pre-commit hock from this repo:
https://github.com/pre-commit/pre-commit-hooks

pip failed when using the shutil.copytree

I've narrowed it to this example, it passed on 2.7-alpine, but fails on 3.5-alpine and 3.6-alpine

FROM python:3.6-alpine

RUN apk update
RUN apk add git

RUN mkdir /bug

RUN cd /bug && ln -s /broken_path/to_nowhere broken
RUN python -c "import shutil; shutil.copytree('/bug', '/temp', symlinks=True)"

EDIT:
After playing around, I've nailed it to this command failing

>>> os.chmod('/bug/broken', 511, follow_symlinks=False)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: [Errno 95] Not supported: '/bug/broken'

shutil was expecting NotImplementedError

this seems related
https://bugs.python.org/issue17076