"pip install -U ." fails when daemon is running with pip 10.0.1

[gvanrossum]

(Originally reported by @ilevkivsky; I can repro.)

It seems pip 10.0.1, when installing from a directory, makes a copy of that directory before doing anything else. When the mypy daemon is running in the mypy directory, this copy fails with the following error:

$ pip3 install -U .
Processing /Users/guido/src/mypy
Could not install packages due to an EnvironmentError: [('/Users/guido/src/mypy/dmypy.sock', '/private/var/folders/63/czkyq6090dd0t157zhx54xvhrdlybt/T/pip-req-build-yucol_r3/dmypy.sock', "[Errno 102] Operation not supported on socket: '/Users/guido/src/mypy/dmypy.sock'")]

Using -v we get the following traceback:

$ pip3 install -U . -v
Created temporary directory: /private/var/folders/63/czkyq6090dd0t157zhx54xvhrdlybt/T/pip-ephem-wheel-cache-z05l_dty
Created temporary directory: /private/var/folders/63/czkyq6090dd0t157zhx54xvhrdlybt/T/pip-install-pdgnid0m
Processing /Users/guido/src/mypy
  Created temporary directory: /private/var/folders/63/czkyq6090dd0t157zhx54xvhrdlybt/T/pip-req-build-cykzr90d
Could not install packages due to an EnvironmentError.
Traceback (most recent call last):
  File "/Users/guido/v36/lib/python3.6/site-packages/pip/_internal/commands/install.py", line 291, in run
    resolver.resolve(requirement_set)
  File "/Users/guido/v36/lib/python3.6/site-packages/pip/_internal/resolve.py", line 103, in resolve
    self._resolve_one(requirement_set, req)
  File "/Users/guido/v36/lib/python3.6/site-packages/pip/_internal/resolve.py", line 257, in _resolve_one
    abstract_dist = self._get_abstract_dist_for(req_to_install)
  File "/Users/guido/v36/lib/python3.6/site-packages/pip/_internal/resolve.py", line 210, in _get_abstract_dist_for
    self.require_hashes
  File "/Users/guido/v36/lib/python3.6/site-packages/pip/_internal/operations/prepare.py", line 310, in prepare_linked_requirement
    progress_bar=self.progress_bar
  File "/Users/guido/v36/lib/python3.6/site-packages/pip/_internal/download.py", line 824, in unpack_url
    unpack_file_url(link, location, download_dir, hashes=hashes)
  File "/Users/guido/v36/lib/python3.6/site-packages/pip/_internal/download.py", line 700, in unpack_file_url
    shutil.copytree(link_path, location, symlinks=True)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/shutil.py", line 359, in copytree
    raise Error(errors)
shutil.Error: [('/Users/guido/src/mypy/dmypy.sock', '/private/var/folders/63/czkyq6090dd0t157zhx54xvhrdlybt/T/pip-req-build-cykzr90d/dmypy.sock', "[Errno 102] Operation not supported on socket: '/Users/guido/src/mypy/dmypy.sock'")]
Cleaning up...

A simple workaround is to stop the daemon (or if it's been killed, rm dmypy.sock).

Perhaps we should report this with the pip project?

[gvanrossum]

Closing this, I'm declaring this a pip bug.

[ilevkivskyi]

Closing this, I'm declaring this a pip bug.

OK, and thanks for workaround!