aclose root_render_func in generate_async

CHANGES.rst

@@ -8,6 +8,7 @@ Unreleased
 -   Use modern packaging metadata with ``pyproject.toml`` instead of ``setup.cfg``.
     :pr:`1793`
 -   Use ``flit_core`` instead of ``setuptools`` as build backend.
+-   Avoid leaving ``root_render_func()`` unclosed in ``Template.generate_async``.
 
 
 Version 3.1.3

src/jinja2/environment.py

@@ -1369,8 +1369,14 @@ async def generate_async(
         ctx = self.new_context(dict(*args, **kwargs))
 
         try:
-            async for event in self.root_render_func(ctx):  # type: ignore
-                yield event
+            agen = self.root_render_func(ctx)
+            try:
+                async for event in agen:  # type: ignore
+                    yield event
+            finally:
+                # we can't use async with aclosing(...) because that's only
+                # in 3.10+
+                await agen.aclose()  # type: ignore
         except Exception:
             yield self.environment.handle_exception()