From 563e99d0711bf8ddc2bd3131a0fb02ca440b9755 Mon Sep 17 00:00:00 2001
From: Nathan Zimmerman <npzimmerman@gmail.com>
Date: Wed, 4 Dec 2024 12:17:44 -0600
Subject: [PATCH] Wrap sync fs for xarray.to_zarr

---
 src/zarr/storage/fsspec.py      |  4 ++++
 tests/test_store/test_fsspec.py | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/zarr/storage/fsspec.py b/src/zarr/storage/fsspec.py
index c9edd8f8ac..b588c763a9 100644
--- a/src/zarr/storage/fsspec.py
+++ b/src/zarr/storage/fsspec.py
@@ -3,6 +3,8 @@
 import warnings
 from typing import TYPE_CHECKING, Any
 
+from fsspec.implementations.asyn_wrapper import AsyncFileSystemWrapper
+
 from zarr.abc.store import ByteRangeRequest, Store
 from zarr.storage.common import _dereference_path
 
@@ -166,6 +168,8 @@ def from_url(
         opts = {"asynchronous": True, **opts}
 
         fs, path = url_to_fs(url, **opts)
+        if not fs.async_impl:
+            fs = AsyncFileSystemWrapper(fs)
 
         # fsspec is not consistent about removing the scheme from the path, so check and strip it here
         # https://github.com/fsspec/filesystem_spec/issues/1722
diff --git a/tests/test_store/test_fsspec.py b/tests/test_store/test_fsspec.py
index b307f2cdf4..c8953f6027 100644
--- a/tests/test_store/test_fsspec.py
+++ b/tests/test_store/test_fsspec.py
@@ -6,6 +6,7 @@
 
 import pytest
 from botocore.session import Session
+from fsspec.implementations.asyn_wrapper import AsyncFileSystemWrapper
 
 import zarr.api.asynchronous
 from zarr.core.buffer import Buffer, cpu, default_buffer_prototype
@@ -214,3 +215,19 @@ async def test_empty_nonexistent_path(self, store_kwargs) -> None:
         store_kwargs["path"] += "/abc"
         store = await self.store_cls.open(**store_kwargs)
         assert await store.is_empty("")
+
+
+def test_wrap_sync_filesystem():
+    """The local fs is not async so we should expect it to be wrapped automatically"""
+    store = FsspecStore.from_url("local://test/path")
+
+    assert isinstance(store.fs, AsyncFileSystemWrapper)
+    assert store.fs.async_impl
+
+
+def test_no_wrap_async_filesystem():
+    """An async fs should not be wrapped automatically; fsspec's https filesystem is such an fs"""
+    store = FsspecStore.from_url("https://test/path")
+
+    assert not isinstance(store.fs, AsyncFileSystemWrapper)
+    assert store.fs.async_impl