TypeError: string argument expected, got 'NoneType' while installing gdbgui by pip

[iosmanthus]

Describe the bug
when I try to install gdbgui in another machine by pip, pip raises an exception:

Exception:
Traceback (most recent call last):
  File "/usr/lib/python3.7/site-packages/pip/_internal/basecommand.py", line 141, in main
    status = self.run(options, args)
  File "/usr/lib/python3.7/site-packages/pip/_internal/commands/install.py", line 299, in run
    resolver.resolve(requirement_set)
  File "/usr/lib/python3.7/site-packages/pip/_internal/resolve.py", line 102, in resolve
    self._resolve_one(requirement_set, req)
  File "/usr/lib/python3.7/site-packages/pip/_internal/resolve.py", line 261, in _resolve_one
    check_dist_requires_python(dist)
  File "/usr/lib/python3.7/site-packages/pip/_internal/utils/packaging.py", line 46, in check_dist_requires_python
    feed_parser.feed(metadata)
  File "/usr/lib/python3.7/email/feedparser.py", line 175, in feed
    self._input.push(data)
  File "/usr/lib/python3.7/email/feedparser.py", line 103, in push
    self._partial.write(data)
TypeError: string argument expected, got 'NoneType'

Screenshots

Please complete the following information:

• OS:
  ArchLinux
• gdb version (gdb -v):
  GNU gdb (GDB) 8.2
• browser [e.g. chrome, safari]:
  chrome
• python packages (pip freeze):

appdirs==1.4.3
backcall==0.1.0
beautifulsoup4==4.6.3
Brlapi==0.6.7
btrfsutil==1.0.0
CacheControl==0.12.5
chardet==3.0.4
click==6.7
colorama==0.3.9
cycler==0.10.0
decorator==4.3.0
distlib==0.2.7
distro==1.3.0
et-xmlfile==1.0.1
Flask==0.12.4
Flask-Compress==1.4.0
Flask-SocketIO==2.9.6
gevent==1.3.6
gmpy2==2.1.0a2
greenlet==0.4.15
html5lib==1.0.1
idna==2.7
ipython==6.5.0
ipython-genutils==0.1.0
itsdangerous==0.24
jdcal==1.4
jedi==0.12.1
Jinja2==2.10
kiwisolver==1.0.1
lensfun==0.3.2
lockfile==0.12.2
louis==3.7.0
lxml==4.2.5
MarkupSafe==1.0
matplotlib==2.2.3
msgpack==0.5.6
openpyxl==2.5.7
packaging==17.1
parso==0.3.1
pexpect==4.6.0
pickleshare==0.7.4
progress==1.4
prompt-toolkit==1.0.15
psutil==5.4.7
ptyprocess==0.6.0
pycairo==1.17.0
pygdbmi==0.8.3.0
Pygments==2.2.0
PyGObject==3.30.1
pyparsing==2.2.1
pyte==0.8.0
python-dateutil==2.7.3
python-engineio==2.2.0
python-socketio==2.0.0
pytoml==0.1.16
pytz==2018.5
pyxdg==0.26
requests==2.19.1
retrying==1.3.3
scipy==1.1.0
shadowsocks==2.9.1
simplegeneric==0.8.1
six==1.11.0
team==1.0
thefuck==3.27
traitlets==4.3.2
urllib3==1.23
wcwidth==0.1.7
webencodings==0.5.1
Werkzeug==0.14.1
ydcv==0.5

[cs01]

Thanks for reporting. I'll try to reproduce and fix the issue. Looks like it might have something to do with Python 3.7.

What was the command you ran? pip install gdbgui? You mentioned you tried to install "in another machine", was there anything unique or unusual about the setup?