Fix/empty listdir (#2225)

* fix(store): report store is empty if no files are present in root
directory

* parse dtype again

Author: jhamman

src/zarr/core/array_spec.py

@@ -3,11 +3,11 @@
 from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any, Literal
 
+import numpy as np
+
 from zarr.core.common import parse_fill_value, parse_order, parse_shapelike
 
 if TYPE_CHECKING:
-    import numpy as np
-
     from zarr.core.buffer import BufferPrototype
     from zarr.core.common import ChunkCoords
 
@@ -29,11 +29,12 @@ def __init__(
         prototype: BufferPrototype,
     ) -> None:
         shape_parsed = parse_shapelike(shape)
+        dtype_parsed = np.dtype(dtype)
         fill_value_parsed = parse_fill_value(fill_value)
         order_parsed = parse_order(order)
 
         object.__setattr__(self, "shape", shape_parsed)
-        object.__setattr__(self, "dtype", dtype)
+        object.__setattr__(self, "dtype", dtype_parsed)
         object.__setattr__(self, "fill_value", fill_value_parsed)
         object.__setattr__(self, "order", order_parsed)
         object.__setattr__(self, "prototype", prototype)

src/zarr/store/local.py

@@ -93,11 +93,15 @@ async def clear(self) -> None:
 
     async def empty(self) -> bool:
         try:
-            subpaths = os.listdir(self.root)
+            with os.scandir(self.root) as it:
+                for entry in it:
+                    if entry.is_file():
+                        # stop once a file is found
+                        return False
         except FileNotFoundError:
             return True
         else:
-            return not subpaths
+            return True
 
     def __str__(self) -> str:
         return f"file://{self.root}"

tests/v3/test_store/test_local.py

@@ -35,3 +35,8 @@ def test_store_supports_partial_writes(self, store: LocalStore) -> None:
 
     def test_store_supports_listing(self, store: LocalStore) -> None:
         assert store.supports_listing
+
+    async def test_empty_with_empty_subdir(self, store: LocalStore) -> None:
+        assert await store.empty()
+        (store.root / "foo/bar").mkdir(parents=True)
+        assert await store.empty()