EXCEPTION of type 'FrozenInstanceError' occurred with message: ''

[Hynek Petrak]

Having cmd2 version 0.9.6 with cliff version 2.14.1 I get an error running cliffdemo:

(cliffdemo) help
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/cmd2/cmd2.py", line 1731, in onecmd_plus_hooks
    statement = self.precmd(statement)
  File "/usr/local/lib/python3.6/dist-packages/cliff/interactive.py", line 172, in precmd
    statement.command = cmd_name
  File "/usr/local/lib/python3.6/dist-packages/attr/_make.py", line 429, in _frozen_setattrs
    raise FrozenInstanceError()
attr.exceptions.FrozenInstanceError
EXCEPTION of type 'FrozenInstanceError' occurred with message: ''

[Doug Hellmann (doug-hellmann)]

It looks like we're going to have to create a new Statement object there, since they have marked the attributes of the Statement class as frozen. Let me know if you want to work on that. I'm available for code review and other pointers if you need them.

[Doug Hellmann (doug-hellmann)]

https://review.openstack.org/#/c/629269/1

[Matthew Thode (prometheanfire)]

does 0.9.7 help?

[Tony PROUM (ptone)]

Hi,
I've got the same issue using Python 3.7 to build a cliff app.
Using Python 2.7 there is no issue.

This only happens when I entered in interactive mode, using command line arguments, it works fine.

[Tony PROUM (ptone)]

Same error with python 3.5

[Nicolas Duchon (buchdag)]

Same with python 3.6.7

[XiaoRuiguo (705437650-6)]

(mistral) workflow-create workflow.yaml
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/cmd2/cmd2.py", line 1739, in onecmd_plus_hooks
    statement = self.precmd(statement)
  File "/usr/local/lib/python3.6/dist-packages/cliff/interactive.py", line 172, in precmd
    statement.command = cmd_name
  File "/usr/local/lib/python3.6/dist-packages/attr/_make.py", line 428, in _frozen_setattrs
    raise FrozenInstanceError()
attr.exceptions.FrozenInstanceError
EXCEPTION of type 'FrozenInstanceError' occurred with message: ''

[Steven Almeroth (stavrosian)]

Doug Hellman's patch rolling back `cmd2` to 0.8.9 worked for me on Python 3.7.3

    cmd2 = ">0.8.3,<0.9.0"

https://bugs.launchpad.net/python-cliff/+bug/1810213/comments/2

[Eric Miller (erickmiller)]

It seems that this problem happens even with the patch mentioned in #8.

I have tried Python 2.7, 3.5, 3.6, and 3.7.3 with similar results when NOT using the patch, building the python-openstackclient package from source:

(openstack) flavor list
Traceback (most recent call last):
  File "/usr/lib/python3.5/site-packages/cmd2/cmd2.py", line 1804, in onecmd_plus_hooks
    statement = self.precmd(statement)
  File "/usr/lib/python3.5/site-packages/cliff/interactive.py", line 172, in precmd
    statement.command = cmd_name
  File "/usr/lib/python3.5/site-packages/attr/_make.py", line 428, in _frozen_setattrs
    raise FrozenInstanceError()
attr.exceptions.FrozenInstanceError
EXCEPTION of type 'FrozenInstanceError' occurred with message: ''

When using the patch, the "flavor list" command above hangs, the CPU is pegged for the openstack process, and memory is slowly eaten until Linux kills the process.

I have yet to come up with a workaround by just trying a number of things without fully understanding how cliff and cmd2 work. Any ideas? The openstackclient is broken in interactive mode until we have a workaround.

Eric

[Eric Miller (erickmiller)]

I just noticed that my copy/paste of the error was from when I was using Python 3.5, but the same error is returned with Python 3.7.3:

(openstack) flavor list
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/cmd2/cmd2.py", line 1804, in onecmd_plus_hooks
    statement = self.precmd(statement)
  File "/usr/local/lib/python3.7/site-packages/cliff/interactive.py", line 172, in precmd
    statement.command = cmd_name
  File "/usr/local/lib/python3.7/site-packages/attr/_make.py", line 428, in _frozen_setattrs
    raise FrozenInstanceError()
attr.exceptions.FrozenInstanceError
EXCEPTION of type 'FrozenInstanceError' occurred with message: ''

[Thomas Bechtold (toabctl)]

This is still broken with python3.7 and cmd2==0.9.18

[Felix Yan (felixonmars)]

Please try my patch: https://review.opendev.org/#/c/712591/