Adding tag(only) in viewport throws error while saving file

[sudhih]

Hello,
I'm running nvim v0.6.1, python 3.8.10, taskwarrior v2.5.1 , tasklib v2.4.3 & pynvim v0.4.3

Steps to reproduce:

1. create view port like below. Here filter is only tag

# TODO | +work

2. save file
3. Error seen

Error invoking 'python_execute' on channel 4 (python3-script-host):
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/sudhir/.local/share/nvim/plugged/taskwiki/taskwiki/errors.py", line 26, in wrapped_funct
ion
    original_function(*args, **kwargs)
  File "/home/sudhir/.local/share/nvim/plugged/taskwiki/taskwiki/decorators.py", line 10, in wrapped_f
unction
    original_function(*args, **kwargs)
  File "/home/sudhir/.local/share/nvim/plugged/taskwiki/taskwiki/main.py", line 65, in update_to_tw
    c.buffer.push()
  File "/home/sudhir/.local/share/nvim/plugged/taskwiki/taskwiki/cache.py", line 29, in push
    buffer[:] = self.data
  File "/usr/lib/python3/dist-packages/pynvim/api/buffer.py", line 65, in __setitem__
    return self.request('nvim_buf_set_lines', start, end, False, lines)
  File "/usr/lib/python3/dist-packages/pynvim/api/common.py", line 58, in request
    return self._session.request(name, self, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/pynvim/api/nvim.py", line 182, in request
    res = self._session.request(name, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/pynvim/msgpack_rpc/session.py", line 104, in request
    raise self.error_wrapper(err)
pynvim.api.common.NvimError: String cannot contain newlines

Please note:
if I use view port like below, no errors while saving. But marking task as done or undone doesn't seem to have the same effect in task warrior. Meaning, if I mark a task as done in nvim, the same is still PENDING in taskwarrior.

## TODO | project:x +work

OR

## TODO | project:x