fix: keep add_line comments from swallowing the closing bracket

tests/test_items.py

@@ -559,6 +559,14 @@ def test_array_add_line() -> None:
     )
 
 
+def test_array_add_line_comment_does_not_comment_out_closing_bracket() -> None:
+    array = api.array()
+    array.add_line("foo", comment="bar")
+    rendered = array.as_string()
+    assert rendered == '[\n    "foo", # bar\n]'
+    parse(f"array = {rendered}")
+
+
 def test_array_add_line_multiline_comment_is_rejected() -> None:
     t = api.array()
     with pytest.raises(ValueError, match="line breaks"):

tomlkit/items.py

@@ -1464,7 +1464,16 @@ def multiline(self, multiline: bool) -> Array:
 
     def as_string(self) -> str:
         if not self._multiline or not self._value:
-            return f"[{''.join(v.as_string() for v in self._iter_items())}]"
+            items = list(self._iter_items())
+            body = "".join(v.as_string() for v in items)
+            # A trailing line comment would otherwise swallow the closing ']'.
+            if (
+                items
+                and isinstance(items[-1], Comment)
+                and not body.endswith(("\n", "\r"))
+            ):
+                body += "\n"
+            return f"[{body}]"
 
         s = "[\n"
         s += "".join(