FutureWarning for sdba migration to xsdba

[Zeitsperre]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR partially satisfies Split xlim.sdba into xsdba #2074
  • This PR partially satisfies Xclim Development Goals 2025 #2047
• Tests for the changes have been added (for bug fixes / features)
  • (If applicable) Documentation has been added / updated (for bug fixes / features)
• CHANGELOG.rst has been updated (with summary of main changes)
  • Link to issue (:issue:number) and pull request (:pull:number) has been added

What kind of change does this PR introduce?

• Adds a FutureWarning emitted on import of xclim.sdba
• Adds Warning messages to the API docs page and autogenerated documentation.
• Adds a workflow that posts a warning message on Pull Requests that modify the xclim.sdba module. Without approval, merging is explicitly blocked.

Does this PR introduce a breaking change?

Yes. xclim.sdba is now officially in the process of being deprecated.

Other information:

https://github.com/Ouranosinc/xsdba

[aulemahal]

Agreed!

Do we want to lay out a plan for deprecation right now ? Like what I suggested in the slack:

0.55 : FutureWarning
0.56 :  Switch xclim.sdba with xsdba (xsdba as opt dep of xclim), DeprecationWarning
0.57 : Full split, remove xclim.sdba

This suggested plan was only an idea, maybe that's too fast ?

[Zeitsperre]

Do we want to lay out a plan for deprecation right now ? Like what I suggested in the slack:

0.55 : FutureWarning
0.56 :  Switch xclim.sdba with xsdba (xsdba as opt dep of xclim), DeprecationWarning
0.57 : Full split, remove xclim.sdba

This suggested plan was only an idea, maybe that's too fast ?

I think you're right that it's a bit fast. What if we were to transition over a longer period? i.e.

0.55 : FutureWarning
0.56 : Switch xclim.sdba with xsdba (xsdba as opt dep of xclim), DeprecationWarning
0.59 / Summer 2025 : Full split, remove xclim.sdba

This would give users a few months to adapt to the changes while the integration kinks can be worked out on the xscen side. Thoughts?

[aulemahal]

A whole 4 versions with a warning emitted each time you import a package seems long to me... Another solution could be:

0.56 (March)       : FutureWarning
0.57 (April / May) : Switch xclim.sdba with xsdba (xsdba as opt dep of xclim), DeprecationWarning
0.58 (Summer)      : Full split, remove xclim.sdba

I.e. wait for the xscen test to be successful before launching the process. I also included in this estimate a guess that xclim's development won't be 1 release/month in the next half-year 😅

[Zeitsperre]

We can hold off if we think that's best. @tlogan2000, what say you?

[tlogan2000]

We can hold off if we think that's best. @tlogan2000, what say you?

ok with me

[Zeitsperre]

OK, let's push this to v0.56. I'll merge this right after the next release.