DEPR: rename startingMonth to starting_month (argument in BQuarterBegin)

[gboeker]

• closes DEPR: rename startingMonth to starting_month (argument in BQuarterBegin) #57794
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[Aloqeely]

You need to deprecate startingMonth first

[gboeker]

Thanks @Aloqeely ! Could you explain to me how I can deprecate startingMonth?

[Aloqeely]

Basically you should still allow startingMonth, but if it is used you should warn the user that it will be removed soon
I think a check in __init__ will do the job but I'm not sure, cc @jbrockmendel

[jbrockmendel]

yah, as @Aloqeely said, you'll want to do something like

def __init__(self, ..., startingMonth=no_default, *, starting_month=no_default):
   if startingMonth is not no_default:
      warnings.warn(...)  # <- tell them to use starting_month instead
      starting_month = startingMonth

[gboeker]

Hi Brock, I changed it to the following:

    def __init__(self, n=1, normalize=False, startingMonth=None,
                 *, starting_month=None):
        if startingMonth is not None:
            warnings.warn(
                "`startingMonth` is deprecated and will be removed in a future "
                "version. Use `starting_month` instead",
                DeprecationWarning
            )
            starting_month = startingMonth

        BaseOffset.__init__(self, n, normalize)

        if starting_month is None:
            starting_month = self._default_starting_month
        self.starting_month = starting_month

Does this look right?

[mroeschke]

Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.