Deprecate the function esmvalcore.var_name_constraint

[schlunma]

Description

This PR adds an API documentation for the module esmvalcore.iris_helpers deprecates the function var_name_constraint in it. It replaces it with iris' NameConstraint class.

Note: I didn't remove the appearances of var_name_constraint in the ICON CMORizer on purpose since they are fixed in #1549 and I want to avoid merge conflicts.

Closes #1536
Closes #1537

Link to documentation: https://esmvaltool--1592.org.readthedocs.build/projects/ESMValCore/en/1592/api/esmvalcore.iris_helpers.html

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[codecov]

Codecov Report

Merging #1592 (65265e2) into main (11cd9cb) will increase coverage by 0.00%.
The diff coverage is 62.96%.

@@           Coverage Diff           @@
##             main    #1592   +/-   ##
=======================================
  Coverage   90.83%   90.83%           
=======================================
  Files         200      200           
  Lines       10644    10648    +4     
=======================================
+ Hits         9668     9672    +4     
  Misses        976      976           

Impacted Files	Coverage Δ
esmvalcore/preprocessor/_derive/lvp.py	50.00% <25.00%> (ø)
esmvalcore/preprocessor/_derive/vegfrac.py	41.66% <25.00%> (ø)
esmvalcore/preprocessor/_derive/lwp.py	40.74% <33.33%> (ø)
esmvalcore/preprocessor/_derive/_shared.py	88.31% <50.00%> (ø)
esmvalcore/preprocessor/_derive/sm.py	52.94% <50.00%> (ø)
esmvalcore/cmor/_fixes/shared.py	100.00% <100.00%> (ø)
esmvalcore/iris_helpers.py	100.00% <100.00%> (ø)
esmvalcore/preprocessor/_derive/alb.py	100.00% <100.00%> (ø)

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[schlunma]

Sorry, I can't add all these missing tests for the variable derivation here...

[valeriupredoi]

excellent enhancement, Manu! Two questions: is the class NameConstraint available for only the latest iris, or - what's the minimum version of iris it is available in - since we must pin on that one? And the second question: do we have a list somewhere where we add all these deprecations, so we remember to remove them in said versions? 🍺

[valeriupredoi]

oh and don't worry about the coverage issue, we need tests for those to begin with, but we'll plop them in a future PR 👍

[schlunma]

Cheers V, thanks for the review! 🚀

is the class NameConstraint available for only the latest iris, or - what's the minimum version of iris it is available in - since we must pin on that one?

Apparently it has been added in 2.4, so we should be fine here 😆

And the second question: do we have a list somewhere where we add all these deprecations, so we remember to remove them in said versions? beer

That's a very good idea! Afaik we don't have this list yet, but I will open an issue to create one.

[valeriupredoi]

great, cheers, Manu!