[2.1.x] Refs #28748 -- Reallowed lazy model field choices.

Regression in 3aa9ab39cce6b2a27d6334ad0148c8f37b6f5986.

Backport of c03e41712b2274f524d32bc2aef455ed82c9e3b4 from master

1 files changed, 3 insertions, 3 deletions

diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index f21a6df7f7..50d22bef0c 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -244,10 +244,10 @@ class Field(RegisterLookupMixin):
         if not self.choices:
             return []
 
-        def is_value(value):
-            return isinstance(value, (str, Promise)) or not is_iterable(value)
+        def is_value(value, accept_promise=True):
+            return isinstance(value, (str, Promise) if accept_promise else str) or not is_iterable(value)
 
-        if is_value(self.choices):
+        if is_value(self.choices, accept_promise=False):
             return [
                 checks.Error(
                     "'choices' must be an iterable (e.g., a list or tuple).",