Refs #29899 -- Moved resolve_relation() to django.db.migrations.utils.

1 files changed, 29 insertions, 0 deletions

diff --git a/django/db/migrations/utils.py b/django/db/migrations/utils.py
index 8939794e59..7ce2c5bc82 100644
--- a/django/db/migrations/utils.py
+++ b/django/db/migrations/utils.py
@@ -1,6 +1,8 @@
 import datetime
 import re
 
+from django.db.models.fields.related import RECURSIVE_RELATIONSHIP_CONSTANT
+
 COMPILED_REGEX_TYPE = type(re.compile(''))
 
 
@@ -15,3 +17,30 @@ class RegexObject:
 
 def get_migration_name_timestamp():
     return datetime.datetime.now().strftime("%Y%m%d_%H%M")
+
+
+def resolve_relation(model, app_label=None, model_name=None):
+    """
+    Turn a model class or model reference string and return a model tuple.
+
+    app_label and model_name are used to resolve the scope of recursive and
+    unscoped model relationship.
+    """
+    if isinstance(model, str):
+        if model == RECURSIVE_RELATIONSHIP_CONSTANT:
+            if app_label is None or model_name is None:
+                raise TypeError(
+                    'app_label and model_name must be provided to resolve '
+                    'recursive relationships.'
+                )
+            return app_label, model_name
+        if '.' in model:
+            app_label, model_name = model.split('.', 1)
+            return app_label, model_name.lower()
+        if app_label is None:
+            raise TypeError(
+                'app_label must be provided to resolve unscoped model '
+                'relationships.'
+            )
+        return app_label, model.lower()
+    return model._meta.app_label, model._meta.model_name