Fix reporting of bad inputs in LiteralInput widget (#202).

[lebedov]

No description provided.

[codecov-io]

Codecov Report

Merging #203 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #203      +/-   ##
==========================================
+ Coverage   90.06%   90.06%   +<.01%     
==========================================
  Files          30       30              
  Lines        4872     4874       +2     
==========================================
+ Hits         4388     4390       +2     
  Misses        484      484

Impacted Files	Coverage Δ
panel/widgets.py	95.63% <100%> (+0.01%)	⬆️

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[philippjfr]

Thanks for the PR. Would you mind adding a test to try to cover the case this is trying to fix?

[lebedov]

Assuming I've understood the unit tests correctly, the last assert in the following code should fail on the bug I observed:

from pyviz_comms import Comm
from bokeh.document import Document
from panel.widgets import LiteralInput

doc = Document()
comm = Comm()

literal = LiteralInput(value=0, type=int, name='Literal')
box = literal._get_model(doc, comm=comm)
widget = box.children[0]
assert widget.title == 'Literal'
literal._comm_change({'value': "invalid"})
assert widget.title == 'Literal (invalid)'
literal._comm_change({'value': "also invalid"})
assert widget.title == 'Literal (invalid)'

However, I don't observe any error when I run it at the command line with unpatched Panel 0.3.1 and pyviz_comm 0.7.0 installed; I can only observe the error (i.e., the title changing from "Literal (invalid)" to "Literal" when I change the contents of the box from "invalid" to "also invalid") if I create a widget in Jupyter Notebook or Lab as follows and try modifying the data in the displayed input box as described:

import panel
from panel.widgets import LiteralInput
panel.extension()
w = LiteralInput(value=0, type=int, name='Literal')
w

Thoughts?

[philippjfr]

I'll try to look into it, also worth noting that the bug doesn't occur on bokeh server so it's something going wrong when syncing the model state in the notebook.

[philippjfr]

I'll merge this without the unit test for now, but will look into the syncing issues this PR highlights.