fix behavior of setitem

Signed-off-by: Frost Ming <[email protected]>

tests/test_toml_document.py

@@ -1147,3 +1147,43 @@ def test_delete_out_of_order_table_key():
 
 """
     )
+
+
+def test_overwrite_out_of_order_table_key():
+    content = """\
+[foo]
+name = "foo"
+
+[bar.a.b]
+name = "bar-a-b"
+
+[foo.a]
+name = "foo-a"
+
+[bar.a]
+name = "bar-a"
+
+[baz]
+name = "baz"
+
+[bar.a.c]
+name = "bar-a-c"
+"""
+    doc = parse(content)
+    doc["bar"]["a"] = {"name": "bar-a-updated"}
+    assert (
+        doc.as_string()
+        == """\
+[foo]
+name = "foo"
+
+[bar.a]
+name = "bar-a-updated"
+[foo.a]
+name = "foo-a"
+
+[baz]
+name = "baz"
+
+"""
+    )

tomlkit/container.py

@@ -835,8 +835,12 @@ def __getitem__(self, key: Key | str) -> Any:
 
     def __setitem__(self, key: Key | str, item: Any) -> None:
         if key in self._tables_map:
-            table = self._tables[self._tables_map[key][-1]]
-            table[key] = item
+            # Overwrite the first table and remove others
+            indices = self._tables_map[key]
+            while len(indices) > 1:
+                table = self._tables[indices.pop()]
+                self._remove_table(table)
+            self._tables[indices[0]][key] = item
         elif self._tables:
             table = self._tables[0]
             table[key] = item