Unable to combine the map and sort filters using the async renderer

[ogenstad]

I would expect this script to return the same output for both the sync and async version:

import asyncio

from jinja2 import DictLoader, Environment, Template, select_autoescape

template_str = """
sorted_letters={{ letters
    | map(attribute='value')
    | sort
 }}
"""

sample_data = [
    {"value": "a"},
    {"value": "d"},
    {"value": "c"},
    {"value": "b"},
]


def get_template(is_async: bool) -> Template:
    env = Environment(
        loader=DictLoader({"template.j2": template_str}),
        autoescape=select_autoescape(),
        enable_async=is_async,
    )

    return env.get_template("template.j2")


def test_sync_render() -> None:
    print("Sync Render:")
    template = get_template(is_async=False)
    result = template.render(letters=sample_data)
    print(result)


async def test_async_render() -> None:
    print("Async Render:")
    template = get_template(is_async=True)
    result = await template.render_async(letters=sample_data)
    print(result)


if __name__ == "__main__":
    test_sync_render()
    asyncio.run(test_async_render())

Output from sync version:

Sync Render:

sorted_letters=['a', 'b', 'c', 'd']

Output from async version:

Async Render:
Traceback (most recent call last):
  File "/Users/patrick/Code/opsmill/infrahub/jinja2_issue.py", line 46, in <module>
    asyncio.run(test_async_render())
  File "/Users/patrick/.nix-profile/lib/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/Users/patrick/.nix-profile/lib/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/patrick/.nix-profile/lib/python3.12/asyncio/base_events.py", line 686, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/Users/patrick/Code/opsmill/infrahub/jinja2_issue.py", line 40, in test_async_render
    result = await template.render_async(letters=sample_data)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/patrick/.virtualenvs/infrahub/lib/python3.12/site-packages/jinja2/environment.py", line 1318, in render_async
    return self.environment.handle_exception()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/patrick/.virtualenvs/infrahub/lib/python3.12/site-packages/jinja2/environment.py", line 942, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "<template>", line 4, in top-level template code
  File "/Users/patrick/.virtualenvs/infrahub/lib/python3.12/site-packages/jinja2/filters.py", line 438, in do_sort
    return sorted(value, key=key_func, reverse=reverse)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: 'async_generator' object is not iterable

Environment:

• Python version: v3.12.8
• Jinja version:3.1.6

As a workaround changing the template to look like this makes it work on both of the variants:

template_str = """
sorted_letters={{ letters
    | map(attribute='value')
    | list
    | sort
 }}
"""