Arch Linux

Description:
Updating python-progress to v1.5 breaks pip due to missing helpers.
Build is also broken due to missing imported modules from python-progress (progress was restructured between v1.4 and v1.5)

Additional info:
Versions affected: python-pip=18.1-1, python-progress=1.5-1
Upstream change to python-progress that breaks pip:
https://github.com/verigak/progress/commit/d9d40736d608a9dcf5476c5e4c4f7eb2de15fc4b


Steps to reproduce:
1. Update python-progress
2. $ pip --version


Error Message:

Traceback (most recent call last):
File "/usr/bin/pip", line 11, in <module>
load_entry_point('pip==18.1', 'console_scripts', 'pip')()
File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 489, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)
File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2793, in load_entry_point
return ep.load()
File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2411, in load
return self.resolve()
File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2417, in resolve
module = __import__(self.module_name, fromlist=['__name__'], level=0)
File "/usr/lib/python3.7/site-packages/pip/_internal/__init__.py", line 40, in <module>
from pip._internal.cli.autocompletion import autocomplete
File "/usr/lib/python3.7/site-packages/pip/_internal/cli/autocompletion.py", line 8, in <module>
from pip._internal.cli.main_parser import create_main_parser
File "/usr/lib/python3.7/site-packages/pip/_internal/cli/main_parser.py", line 8, in <module>
from pip._internal.cli import cmdoptions
File "/usr/lib/python3.7/site-packages/pip/_internal/cli/cmdoptions.py", line 22, in <module>
from pip._internal.utils.ui import BAR_TYPES
File "/usr/lib/python3.7/site-packages/pip/_internal/utils/ui.py", line 15, in <module>
from pip._vendor.progress.helpers import HIDE_CURSOR, SHOW_CURSOR, WritelnMixin
ModuleNotFoundError: No module named 'pip._vendor.progress.helpers'