[visibility-sheet] Causes traceback

[frosencrantz]

Small description
visibility-sheet causes traceback

Expected result
No tracback when making rows mult.

Actual result with screenshot

Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/visidata/mainloop.py", line 38, in drawSheet
    sheet.draw(scr)
  File "/usr/lib/python3.9/site-packages/visidata/sheets.py", line 705, in draw
    y += self.drawRow(scr, row, self.topRowIndex+rowidx, y, rowcattr, maxheight=self.windowHeight-y-1, **drawparams)
  File "/usr/lib/python3.9/site-packages/visidata/sheets.py", line 767, in drawRow
    height = min(self.calc_height(row, displines), maxheight) or 1  # display even empty rows
  File "/usr/lib/python3.9/site-packages/visidata/sheets.py", line 732, in calc_height
    lines = _splitcell(self, cellval.display, width=colwidth-2)
  File "/usr/lib/python3.9/site-packages/visidata/extensible.py", line 133, in call_if_not
    return func(self, *args, **kwargs)
  File "/usr/lib/python3.9/site-packages/visidata/sheets.py", line 26, in _splitcell
    for L in s.splitlines():
AttributeError: 'generator' object has no attribute 'splitlines'

https://asciinema.org/a/S3OgdQfnBL8cyOL3TAfWMgDTI

Steps to reproduce with sample data and a .vd
While in a sheet, type v, and get multiple tracebacks due to issue.

Additional context
Please include the version of VisiData. Latest version from develop.

[anjakefala]

Thanks for filing an issue!

We had a fix but it caused a problem with the sidebar, so we decided to not commit it to the repo. Still thinking about how to address this.

[frosencrantz]

I am glad to see new fixes being added to the develop branch. This bug would also be very useful to fix if there is time.

[frosencrantz]

Looks like it was reported again #2019 but with a possible fix from @ajkerrigan (#2020) Hooray!

[ajkerrigan]

We had a fix but it caused a problem with the sidebar, so we decided to not commit it to the repo. Still thinking about how to address this.

Heh looks like I missed multiple flavors of history when looking into this 🙈. What sort of sidebar issues though? Wonder if my PR would have similar effects.

[saulpw]

I believe this is fixed now. Thanks to @ajkerrigan for providing the patch!