fixup

Author: TomAugspurger

src/zarr/abc/store.py

@@ -84,7 +84,25 @@ async def clear(self) -> None: ...
     @abstractmethod
     def with_mode(self, mode: AccessModeLiteral) -> Self:
         """
-        Return a new store pointing to the same location with a new mode.
+        Return a new store of the same type pointing to the same location with a new mode.
+
+        The returned Store is not automatically opened. Call :meth:`Store.open` before
+        using.
+
+        Parameters
+        ----------
+        mode: AccessModeLiteral
+            The new mode to use.
+
+        Returns
+        -------
+        store:
+            A new store of the same type with the new mode.
+
+        Examples
+        --------
+        >>> writer = zarr.store.MemoryStore(mode="w")
+        >>> reader = writer.with_mode("r")
         """
         ...
 

src/zarr/store/zip.py

@@ -118,9 +118,7 @@ async def empty(self) -> bool:
                 return True
 
     def with_mode(self, mode: ZipStoreAccessModeLiteral) -> Self:  # type: ignore[override]
-        return type(self)(
-            path=self.path, mode=mode, compression=self.compression, allowZip64=self.allowZip64
-        )
+        raise NotImplementedError("ZipStore cannot be reopened with a new mode.")
 
     def __str__(self) -> str:
         return f"zip://{self.path}"

src/zarr/testing/store.py

@@ -254,8 +254,26 @@ async def test_list_dir(self, store: S) -> None:
         assert sorted(keys_expected) == sorted(keys_observed)
 
     async def test_with_mode(self, store: S) -> None:
-        for mode in ["r", "w"]:
+        data = b"0000"
+        self.set(store, "key", self.buffer_cls.from_bytes(data))
+        assert self.get(store, "key").to_bytes() == data
+
+        for mode in ["r", "a"]:
             mode = cast(AccessModeLiteral, mode)
-            result = store.with_mode(mode)
-            assert result.mode == AccessMode.from_literal(mode)
-            assert isinstance(result, type(store))
+            clone = store.with_mode(mode)
+            # await store.close()
+            await clone._ensure_open()
+            assert clone.mode == AccessMode.from_literal(mode)
+            assert isinstance(clone, type(store))
+
+            # earlier writes are visible
+            assert self.get(clone, "key").to_bytes() == data
+
+            # writes to original after with_mode is visible
+            self.set(store, "key-2", self.buffer_cls.from_bytes(data))
+            assert self.get(clone, "key-2").to_bytes() == data
+
+            if mode == "w":
+                # writes to clone is visible in the original
+                self.set(store, "key-3", self.buffer_cls.from_bytes(data))
+                assert self.get(clone, "key-3").to_bytes() == data

tests/v3/test_store/test_zip.py

@@ -96,3 +96,7 @@ def test_api_integration(self, store: ZipStore) -> None:
             del root["bar"]
 
         store.close()
+
+    async def test_with_mode(self, store: ZipStore) -> None:
+        with pytest.raises(NotImplementedError, match="new mode"):
+            await super().test_with_mode(store)