6.27.0 broke the %edit magic

[ccordoba12]

• We have a test for that magic in Spyder and it started to fail with 6.27.0.
• I checked locally and can confirm that that's the case: the magic works well in 6.26.0 but fails in 6.27.0
• My guess is that the problem was introduced by the changes done in PR Extend argument handling of do_execute with cell metadata #1169.

@blink1073, could you take a look at this one? I'd love to help but unfortunately I don't have time to do it right now.

[blink1073]

I've yanked the 6.27.0 release, I'll see about adding tests for some magics before releasing again.

[blink1073]

Can you point me to your existing tests?

[ccordoba12]

It's this one:

https://github.com/spyder-ide/spyder/blob/06a148be300ca830fa74b69c20105cd8f72a3c72/spyder/app/tests/test_mainwindow.py#L84

What we do is testing that running %edit foo.py in the console opens foo.py in our editor. I don't know how to test that only in the kernel.

[blink1073]

This was actually the offending change, from my linting PR. Path vs str, tricky...