fix: Clear the existing table header (#234)

Author: frostming

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Clear the existing table header when it is adding to another table. ([#230](https://github.com/sdispater/tomlkit/issues/230))
+
 ## [0.11.4] - 2022-08-12
 
 ### Fixed

tests/test_toml_document.py

@@ -1001,3 +1001,32 @@ def test_remove_item_from_super_table():
 
     """
     assert doc.as_string() == dedent(expected)
+
+
+def test_nested_table_update_display_name():
+    content = """\
+    [parent]
+
+    [parent.foo]
+    x = 1
+    """
+
+    doc = parse(dedent(content))
+    sub = """\
+    [foo]
+    y = 2
+
+    [bar]
+    z = 3
+    """
+    doc["parent"].update(parse(dedent(sub)))
+    expected = """\
+    [parent]
+
+    [parent.foo]
+    y = 2
+
+    [parent.bar]
+    z = 3
+    """
+    assert doc.as_string() == dedent(expected)

tomlkit/container.py

@@ -194,7 +194,7 @@ def append(self, key: Union[Key, str, None], item: Item) -> "Container":
         prev = self._previous_item()
         prev_ws = isinstance(prev, Whitespace) or ends_with_whitespace(prev)
         if isinstance(item, Table):
-            if item.name != key.key:
+            if not self._parsed:
                 item.invalidate_display_name()
             if self._body and not (self._parsed or item.trivia.indent or prev_ws):
                 item.trivia.indent = "\n"

tomlkit/items.py

@@ -205,7 +205,7 @@ def item(
                     v.items(),
                     key=lambda i: (isinstance(i[1], dict), i[0] if _sort_keys else 1),
                 ):
-                    i = item(_v, _parent=a, _sort_keys=_sort_keys)
+                    i = item(_v, _parent=table, _sort_keys=_sort_keys)
                     if isinstance(table, InlineTable):
                         i.trivia.trail = ""