From fd8d635b941b20451dcea403a190355d770330dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9B=BE=E6=A5=9A=E7=AC=91?= <eric2114007244@gmail.com>
Date: Wed, 23 Sep 2026 00:10:51 +0800
Subject: [PATCH] Convert containers assigned to BoxList items and slices

---
 AUTHORS.rst           |  1 +
 CHANGES.rst           |  5 ++++
 box/box_list.py       |  6 ++++-
 test/test_box_list.py | 53 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/AUTHORS.rst b/AUTHORS.rst
index 6b44851..7b81ee5 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -37,6 +37,7 @@ Code contributions:
 - Jesper Schlegel (jesperschlegel)
 - J vanBemmel (jbemmel)
 - m-janicki
+- Eric3-jp (with OpenAI Codex assistance)
 
 
 Suggestions and bug reporting:
diff --git a/CHANGES.rst b/CHANGES.rst
index c4a347d..50c3816 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,11 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+* Convert dictionaries and lists assigned to BoxList items and slices, matching append and insert.
+
 Version 7.4.1
 -------------
 
diff --git a/box/box_list.py b/box/box_list.py
index 72609ff..8c2ddb1 100644
--- a/box/box_list.py
+++ b/box/box_list.py
@@ -103,7 +103,7 @@ def __setitem__(self, key, value):
             if pos >= len(self) and self.box_options.get("default_box"):
                 self.extend([None] * (pos - len(self) + 1))
             if len(list_pos.group()) == len(key):
-                return super().__setitem__(pos, value)
+                return super().__setitem__(pos, self._convert(value))
             children = key[len(list_pos.group()) :].lstrip(".")
             if self.box_options.get("default_box"):
                 if children[0] == "[":
@@ -111,6 +111,10 @@ def __setitem__(self, key, value):
                 else:
                     super().__setitem__(pos, self.box_options.get("box_class")(**self.box_options))
             return super().__getitem__(pos).__setitem__(children, value)
+        if isinstance(key, slice):
+            value = [self._convert(item) for item in value]
+        else:
+            value = self._convert(value)
         super().__setitem__(key, value)
 
     def _is_intact_type(self, obj):
diff --git a/test/test_box_list.py b/test/test_box_list.py
index 9cd90e0..709ac30 100644
--- a/test/test_box_list.py
+++ b/test/test_box_list.py
@@ -50,6 +50,59 @@ def test_box_list(self):
         assert isinstance(new_list[1], BoxList)
         assert not isinstance(new_list.to_list(), BoxList)
 
+    @pytest.mark.parametrize("key", [0, -1, "[0]", "[2]"])
+    @pytest.mark.parametrize("nested_list", [False, True])
+    def test_setitem_converts_containers(self, key, nested_list):
+        bl = BoxList([None], box_dots=True, default_box=True, camel_killer_box=True)
+        value = {"CamelKey": 1}
+        bl[key] = [value] if nested_list else value
+
+        item = bl[-1]
+        if nested_list:
+            assert isinstance(item, BoxList)
+            item = item[0]
+        assert isinstance(item, Box)
+        assert item.camel_key == 1
+
+    @pytest.mark.parametrize("key", [slice(None), slice(None, None, 2)])
+    def test_setitem_slice_converts_containers(self, key):
+        bl = BoxList([0, 1, 2], camel_killer_box=True)
+        bl[key] = iter([{"CamelKey": 1}, [{"CamelKey": 2}]])
+
+        assert isinstance(bl[0], Box)
+        assert bl[0].camel_key == 1
+        assert isinstance(bl[-1], BoxList)
+        assert bl[-1][0].camel_key == 2
+        if key.step == 2:
+            assert bl[1] == 1
+
+    def test_setitem_preserves_intact_types(self):
+        class IntactDict(dict):
+            pass
+
+        class IntactList(list):
+            pass
+
+        value = IntactDict(a=1)
+        values = IntactList([value])
+        bl = BoxList([None, None], box_intact_types=(IntactDict, IntactList))
+        bl[0] = value
+        bl[1:] = [values]
+        assert bl[0] is value
+        assert bl[1] is values
+
+    def test_setitem_invalid_extended_slice(self):
+        bl = BoxList([0, 1, 2])
+        with pytest.raises(ValueError):
+            bl[::2] = iter([{"a": 1}])
+        assert bl == [0, 1, 2]
+
+    def test_frozen_list_slice_assignment(self):
+        bl = BoxList([0, 1, 2], frozen_box=True)
+        with pytest.raises(BoxError):
+            bl[:] = [{"a": 1}]
+        assert bl == [0, 1, 2]
+
     def test_frozen_list(self):
         bl = BoxList([5, 4, 3], frozen_box=True)
         with pytest.raises(BoxError):