fix: make a dummy document when rendering a non-document element

Close #188

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

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## Unreleased
 
 - Add pretty representation for the AST for debugging purpose. An extra group `repr` is added for more readable output.
+- Make a dummy `Document` element if the element to render is not a `Document` instance.
 
 ## v2.0.2(2023-11-16)
 

marko/__init__.py

@@ -129,7 +129,6 @@ def render(self, parsed: Document) -> str:
         Override this to handle parsed result.
         """
         self._setup_extensions()
-        self.renderer.root_node = parsed
         with self.renderer as r:
             return r.render(parsed)
 

marko/renderer.py

@@ -51,6 +51,7 @@ def __enter__(self: _T) -> _T:
 
     def __exit__(self, *args: Any) -> None:
         html._charref = _charref_bak  # type: ignore[attr-defined]
+        self.root_node = None
 
     def render(self, element: Element) -> Any:
         """Renders the given element to string.
@@ -60,7 +61,12 @@ def render(self, element: Element) -> Any:
         """
         # Store the root node since it may be required by the render functions
         if not self.root_node:  # pragma: no cover
-            self.root_node = element  # type: ignore
+            if isinstance(element, Document):
+                self.root_node = element
+            else:
+                # Make a dummy root node from it
+                self.root_node = Document()
+                self.root_node.children = [element]
         if hasattr(element, "get_type"):
             func_name = "render_" + element.get_type(snake_case=True)
             render_func = getattr(self, func_name, None)