fix: Table header missing

Fixes #374

Signed-off-by: Frost Ming <me@frostming.com>

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [unreleased]
 
+### Fixed
+
+- Fix the `Table.is_super_table()` check for tables with dotted key as the only child. ([#374](https://github.com/python-poetry/tomlkit/issues/374))
+
 ## [0.13.0] - 2024-07-10
 
 ### Changed

tests/test_items.py

@@ -985,3 +985,11 @@ def test_no_extra_minus_sign():
  assert doc.as_string() == "a = +1.5"
  doc["a"] *= -1
  assert doc.as_string() == "a = -1.5"
+
+
+def test_serialize_table_with_dotted_key():
+ child = api.table()
+ child.add(api.key(("b", "c")), 1)
+ parent = api.table()
+ parent.add("a", child)
+ assert parent.as_string() == "[a]\nb.c = 1\n"

tomlkit/items.py

@@ -1624,8 +1624,18 @@ def is_super_table(self) -> bool:
  # If the table has only one child and that child is a table, then it is a super table.
  if len(self) != 1:
  return False
- only_child = next(iter(self.values()))
- return isinstance(only_child, (Table, AoT))
+ k, only_child = next(iter(self.items()))
+ if not isinstance(k, Key):
+ k = SingleKey(k)
+ index = self.value._map[k]
+ if isinstance(index, tuple):
+ return False
+ real_key = self.value.body[index][0]
+ return (
+ isinstance(only_child, (Table, AoT))
+ and real_key is not None
+ and not real_key.is_dotted()
+ )
 
  def as_string(self) -> str:
  return self._value.as_string()