fix: Empty table dumped when number of subtables > 1 (#378)

Fixes #377

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

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### 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))
+- Count table as a super table if it has children and all children are either tables or arrays of tables. ([#377](https://github.com/python-poetry/tomlkit/issues/377))
 
 ## [0.13.0] - 2024-07-10
 

tests/test_items.py

@@ -993,3 +993,16 @@ def test_serialize_table_with_dotted_key():
     parent = api.table()
     parent.add("a", child)
     assert parent.as_string() == "[a]\nb.c = 1\n"
+
+
+def test_not_showing_parent_header_for_super_table():
+    doc = api.document()
+
+    def add_table(parent, name):
+        parent.add(name, api.table())
+        return parent[name]
+
+    root = add_table(doc, "root")
+    add_table(root, "first")
+    add_table(root, "second")
+    assert doc.as_string() == "[root.first]\n\n[root.second]\n"

tomlkit/items.py

@@ -1621,21 +1621,23 @@ def is_super_table(self) -> bool:
         If true, it won't appear in the TOML representation."""
         if self._is_super_table is not None:
             return self._is_super_table
-        # If the table has only one child and that child is a table, then it is a super table.
-        if len(self) != 1:
+        if not self:
             return False
-        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()
-        )
+        # If the table has children and all children are tables, then it is a super table.
+        for k, child in 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]
+            if (
+                not isinstance(child, (Table, AoT))
+                or real_key is None
+                or real_key.is_dotted()
+            ):
+                return False
+        return True
 
     def as_string(self) -> str:
         return self._value.as_string()