Refs #31262 -- Renamed ChoiceIterator to BaseChoiceIterator.

Some third-party applications, e.g. `django-filter`, already define
their own `ChoiceIterator`, so renaming this `BaseChoiceIterator` will
be a better fit and avoid any potential confusion.

See https://github.com/carltongibson/django-filter/pull/1607.

django/forms/models.py

@@ -21,7 +21,7 @@ from django.forms.widgets import (
     RadioSelect,
     SelectMultiple,
 )
-from django.utils.choices import ChoiceIterator
+from django.utils.choices import BaseChoiceIterator
 from django.utils.text import capfirst, get_text_list
 from django.utils.translation import gettext
 from django.utils.translation import gettext_lazy as _
@@ -1403,7 +1403,7 @@ class ModelChoiceIteratorValue:
         return self.value == other
 
 
-class ModelChoiceIterator(ChoiceIterator):
+class ModelChoiceIterator(BaseChoiceIterator):
     def __init__(self, field):
         self.field = field
         self.queryset = field.queryset

django/utils/choices.py

@@ -3,11 +3,11 @@ from collections.abc import Callable, Iterable, Iterator, Mapping
 from django.utils.functional import Promise
 
 
-class ChoiceIterator:
+class BaseChoiceIterator:
     """Base class for lazy iterators for choices."""
 
 
-class CallableChoiceIterator(ChoiceIterator):
+class CallableChoiceIterator(BaseChoiceIterator):
     """Iterator to lazily normalize choices generated by a callable."""
 
     def __init__(self, func):
@@ -23,7 +23,7 @@ def normalize_choices(value, *, depth=0):
     from django.db.models.enums import ChoicesMeta
 
     match value:
-        case ChoiceIterator() | Promise() | bytes() | str():
+        case BaseChoiceIterator() | Promise() | bytes() | str():
             # Avoid prematurely normalizing iterators that should be lazy.
             # Because string-like types are iterable, return early to avoid
             # iterating over them in the guard for the Iterable case below.