PR: Fix saving variables as .spydata if no file extension is given

[maurerle]

Description of Changes

While this does not fix the major file save dialog problems mentioned in #7196 it allows to save the workspace in a pickle file without finding out which extension is needed.
Currently, .mat and .spydata is supported to write data, and it makes sense to prefer .spydata here.

I also removed the filename option from the save method, as it is never used.
If the method would be called with filename='text.spydata' it would anyway save as self.filename which would be wrong.
So I hope it is fine to remove the optional parameter.

Thank you!

• Wrote at least one-line docstrings (for any new functions)
• Added unit test(s) covering the changes (if testable)

• Included a screenshot or animation (if affecting the UI, see Licecap)

Issue(s) Resolved

Fixes #7196

Affirmation

By submitting this Pull Request or typing my (user)name below,
I affirm the Developer Certificate of Origin
with respect to all commits and content included in this PR,
and understand I am releasing the same under Spyder's MIT (Expat) license.

I certify the above statement is true and correct: Florian Maurer

[dalthviz]

Thank you @maurerle for helping with this! I left a comment requesting some changes (adding a comment to reference the issue and the variable to validate the extension), otherwise this LGTM 👍

As a side note, seems like the original issue post will be addressed with this PR but the root cause discussed there will not (i.e the lack of extensions when using the QFileDialog on Linux: #7196 (comment))

So, should we create a new issue to check that in the future, even maybe that could be something to do on QtPy? What do you think @ccordoba12 ?

[dalthviz]

Hi @maurerle if is okay for you if we add here a commit with the changes to address the minor comments left in the review to proceed with this and merge it? Let us know!

[maurerle]

Ouch. I did not see your review somehow.
Sorry for the long wait.

[pep8speaks]

Hello @maurerle! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2022-07-14 21:29:49 UTC

[maurerle]

Hi @dalthviz,
I tried to address your comment and hope to get this merged soon. Somehow I was did not notice the notification at this PR.

I also renamed the other ext variable in this file for consistency.
Hope this is okay.
Otherwise you are allowed to make edits to this PR as you wish :)

[dalthviz]

Thank you @maurerle ! Could you rebase to the latest 5.x to solve the failing tests? After that I think this should be ready

Edit: Will do a rebase to fix the tests, fix the little PEP8 issue and After the test pass then this sould be ready 👍

[maurerle]

I rebased (which hopefully fixes the tests) and fixed the linting by looking at how other occurances of too long lines are handled.
Hope it is fine like this.

[dalthviz]

Thank you so much @maurerle !

[dalthviz]

Thanks @maurerle ! LGTM 👍🏼