pip install mmseg fails when building docker image of related repo (mmdetection3d)

[JSchuurmans]

Checklist

1. I have searched related issues but cannot get the expected help. Yes
2. The bug has not been fixed in the latest version. No

Describe the bug
Docker cannot build the image. RUN pip install mmseg fails. It looks like a python 2 vs 3 incompatibility. See Error traceback and Bug fix.

Reproduction

1. What command or script did you run?

docker build -t mmdetection3d docker/

2. Did you make any modifications on the code or config? No

Environment

Docker

Error traceback

Step 11/19 : RUN pip install mmseg
 ---> Running in 798c6d89b234
Collecting mmseg
  Downloading mmseg-1.3.0.tar.gz (817 kB)
    ERROR: Command errored out with exit status 1:
     command: /opt/conda/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-ofv4t21p/mmseg/setup.py'"'"'; __file__='"'"'/tmp/pip-install-ofv4t21p/mmseg/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-install-ofv4t21p/mmseg/pip-egg-info
         cwd: /tmp/pip-install-ofv4t21p/mmseg/
    Complete output (5 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-install-ofv4t21p/mmseg/setup.py", line 6, in <module>
        reload(sys)
    NameError: name 'reload' is not defined
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
The command '/bin/sh -c pip install mmseg' returned a non-zero code: 1

Bug fix
Comment out the line that errors. This is not a fix, more like a workaround...

# RUN pip install mmseg

I found the following on https://www.programmersought.com/article/91541059533/ .
ForPython 2.X：

import sys
reload(sys)
sys.setdefaultencoding("utf-8")

For >=Python 3.4:

import importlib
importlib.reload(sys)

[xvjiarui]

Hi @JSchuurmans
Is the error exists if you are not installing in docker?

[Wuziyi616]

@xvjiarui @JSchuurmans I think this bug is solved in open-mmlab/mmdetection3d#563 (comment) because mmdet3d uses a wrong name for mmseg installation (which should be mmsegmentation rather than mmseg). Can close this issue?