fix incorrect use of getattr (#16498)

Author: zzstoatzz

src/prefect/results.py

@@ -245,7 +245,7 @@ async def _call_explicitly_async_block_method(
     see https://github.com/PrefectHQ/prefect/issues/15008
     """
     if hasattr(block, f"a{method}"):  # explicit async method
-        return await getattr(block.__class__.__name__, f"a{method}")(*args, **kwargs)
+        return await getattr(block, f"a{method}")(*args, **kwargs)
     elif hasattr(getattr(block, method, None), "aio"):  # sync_compatible
         return await getattr(block, method).aio(block, *args, **kwargs)
     else:  # should not happen in prefect, but users can override impls

tests/public/results/test_result_storage.py

@@ -0,0 +1,59 @@
+from pathlib import Path
+from unittest.mock import patch
+
+import anyio
+import pytest
+
+from prefect import flow, task
+from prefect.filesystems import LocalFileSystem
+from prefect.results import ResultStore
+
+
+@pytest.fixture
+def custom_storage_block(tmpdir: Path):
+    class Test(LocalFileSystem):
+        _block_type_slug = "test"
+
+        async def awrite_path(self, path: str, content: bytes) -> str:
+            _path: Path = self._resolve_path(path)
+
+            _path.parent.mkdir(exist_ok=True, parents=True)
+
+            if _path.exists() and not _path.is_file():
+                raise ValueError(f"Path {_path} already exists and is not a file.")
+
+            async with await anyio.open_file(_path, mode="wb") as f:
+                await f.write(content)
+            return str(_path)
+
+    Test.register_type_and_schema()
+    test = Test(basepath=str(tmpdir))
+    test.save("test", overwrite=True)
+    return test
+
+
+async def test_async_method_used_in_async_context(
+    custom_storage_block: LocalFileSystem,
+):
+    # this is a regression test for https://github.com/PrefectHQ/prefect/issues/16486
+    with patch.object(
+        custom_storage_block, "awrite_path", wraps=custom_storage_block.awrite_path
+    ) as mock_awrite:
+
+        @task(result_storage=custom_storage_block, result_storage_key="testing")
+        async def t():
+            return "this is a test"
+
+        @flow
+        async def f():
+            return await t()
+
+        result = await f()
+        assert result == "this is a test"
+        store = ResultStore(result_storage=custom_storage_block)
+        stored_result_record = await store.aread("testing")
+
+        assert stored_result_record.result == result == "this is a test"
+        # Verify awrite_path was called
+        mock_awrite.assert_awaited_once()
+        assert mock_awrite.await_args[0][0] == "testing"  # Check path argument