Fixed #35658 -- Initialized InMemoryFileNode instances with a name.

django/core/files/storage/memory.py

@@ -45,10 +45,9 @@ class InMemoryFileNode(ContentFile, TimingMixin):
     modification, and access times.
     """
 
-    def __init__(self, content="", name=""):
-        self.file = None
+    def __init__(self, content="", name=None):
+        super().__init__(content, name)
         self._content_type = type(content)
-        self._initialize_stream()
         self._initialize_times()
 
     def open(self, mode):
@@ -142,7 +141,11 @@ def _resolve_child(self, path_segment, create_if_missing, child_cls):
         if create_if_missing:
             self._update_accessed_time()
             self._update_modified_time()
-            return self._children.setdefault(path_segment, child_cls())
+            if child_cls is InMemoryFileNode:
+                child = child_cls(name=path_segment)
+            else:
+                child = child_cls()
+            return self._children.setdefault(path_segment, child)
         return self._children.get(path_segment)
 
     def listdir(self):

tests/file_storage/tests.py

@@ -1024,6 +1024,23 @@ def test_stringio(self):
         with temp_storage.open("tests/stringio") as f:
             self.assertEqual(f.read(), b"content")
 
+    @override_settings(
+        STORAGES={
+            DEFAULT_STORAGE_ALIAS: {
+                "BACKEND": "django.core.files.storage.InMemoryStorage"
+            }
+        }
+    )
+    def test_create_file_field_from_another_file_field_in_memory_storage(self):
+        f = ContentFile("content", "file.txt")
+        obj = Storage.objects.create(storage_callable_default=f)
+        new_obj = Storage.objects.create(
+            storage_callable_default=obj.storage_callable_default.file
+        )
+        storage = callable_default_storage()
+        with storage.open(new_obj.storage_callable_default.name) as f:
+            self.assertEqual(f.read(), b"content")
+
 
 class FieldCallableFileStorageTests(SimpleTestCase):
     def setUp(self):