Predictions: IndexError when clicking outside the table

[ajdapretnar]

• What's wrong?

Predictions crashes when clicking outside the table fields.

-------------------------- AttributeError Exception ---------------------------
Traceback (most recent call last):
  File "/Users/ajda/orange/orange3/Orange/widgets/evaluate/owpredictions.py", line 1130, in select
    self.store.select(selection, flags)
  File "/Users/ajda/orange/orange3/Orange/widgets/evaluate/owpredictions.py", line 1057, in select
    rows = {selection.model().mapToSource(selection).row()}
AttributeError: 'NoneType' object has no attribute 'mapToSource'
-------------------------------------------------------------------------------

• How can we reproduce the problem?

Create a prediction workflow with a small test data set. Click outside the table.

• What's your environment?

• Operating system: OSX
• Orange version: 3.28.dev
• How you installed Orange:

[erelin6613]

Hey, I would like to take a look at this one, may I? Thanks in advance!

[ajdapretnar]

@erelin6613 Hello! You are welcome to take this over! ⭐

[irgolic]

@erelin6613 Hey, nice to meet you, thanks for the initiative. If you've any questions, feel free to ask on Discord :)

[erelin6613]

@irgolic @ajdapretnar
I have been trying to dig deep into the warning the terminal was displaying:
QCssParser::parseColorValue: Specified color without alpha value but alpha given: 'rgb 0, 0, 0, 100', I am not sure if it might cause issue or not though.
For now I just added functionality to 'just not break' but was not able to discover some deeper problem if there is any. If you have any idea why SharedSelectionStore.selection.model() could return None, I appreciate you for suggestion. Otherwise a fix for stability is available on my forked repo.

[irgolic]

@erelin6613 Create a new branch with your fix on your forked repo, then create a pull request https://github.com/biolab/orange3/compare, and we can see what's up.

You should be able to find some help here: https://docs.github.com/en/free-pro-team@latest/github/collaborating-with-issues-and-pull-requests/working-with-forks