Widen ChunksLike type alias (zarr-developers#3990)

* Widen ChunksLike type alias

Fixes zarr-developers#3869

* Add changelog file.

* Prefer if/else statement to if/else expression

Author: chuckwondo

changes/3990.misc.md

@@ -0,0 +1,5 @@
+Widen `ChunksLike` type alias to use `Iterable` instead of `Sequence`, and also
+remove `None` from the type union.  This supports a broader range of types,
+removing the necessity to "materialize" iterable values simply to satisfy type
+annotations.  It also allows use of `ChunksLike` in cases where `None` should
+not be permitted.

src/zarr/core/array.py

@@ -4397,11 +4397,8 @@ async def init_array(
         chunk_key_encoding, zarr_format=zarr_format
     )
 
-    if overwrite:
-        if store_path.store.supports_deletes:
-            await store_path.delete_dir()
-        else:
-            await ensure_no_existing_node(store_path, zarr_format=zarr_format)
+    if overwrite and store_path.store.supports_deletes:
+        await store_path.delete_dir()
     else:
         await ensure_no_existing_node(store_path, zarr_format=zarr_format)
 
@@ -4417,12 +4414,10 @@ async def init_array(
             )
 
     # Normalize the user's chunks into canonical ChunksTuple form
-    if chunks is None or chunks == "auto":
-        chunks_normalized = guess_chunks(
-            shape_parsed,
-            item_size,
-            max_bytes=SHARDED_INNER_CHUNK_MAX_BYTES if shards is not None else None,
-        )
+
+    if chunks == "auto":
+        max_bytes = None if shards is None else SHARDED_INNER_CHUNK_MAX_BYTES
+        chunks_normalized = guess_chunks(shape_parsed, item_size, max_bytes=max_bytes)
     else:
         chunks_normalized = normalize_chunks_nd(chunks, shape_parsed)
 

src/zarr/core/common.py

@@ -37,7 +37,7 @@
 
 BytesLike = bytes | bytearray | memoryview
 ShapeLike = Iterable[int | np.integer[Any]] | int | np.integer[Any]
-ChunksLike = ShapeLike | Sequence[Sequence[int]] | None
+ChunksLike = ShapeLike | Iterable[Iterable[int]]
 # For backwards compatibility
 ChunkCoords = tuple[int, ...]
 ZarrFormat = Literal[2, 3]