Skip non-Zarr objects silently when listing group members

changes/4161.bugfix.md

@@ -0,0 +1 @@
+Listing the members of a group no longer emits a `ZarrUserWarning` for store objects that are not part of the Zarr hierarchy (such as the temporary `.partial` files created while a write is in progress); these objects are now skipped silently.

src/zarr/core/group.py

@@ -3602,15 +3602,11 @@ async def _iter_members(
     for fetched_node_coro in asyncio.as_completed(node_tasks):
         try:
             fetched_node = await fetched_node_coro
-        except KeyError as e:
+        except KeyError:
             # keyerror is raised when `key` names an object (in the object storage sense),
             # as opposed to a prefix, in the store under the prefix associated with this group
             # in which case `key` cannot be the name of a sub-array or sub-group.
-            warnings.warn(
-                f"Object at {e.args[0]} is not recognized as a component of a Zarr hierarchy.",
-                ZarrUserWarning,
-                stacklevel=1,
-            )
+            # Such objects (e.g. temporary files from an in-progress write) are skipped silently.
             continue
         match fetched_node:
             case AsyncArray() | AsyncGroup():

tests/test_group.py

@@ -217,38 +217,42 @@ def test_group_members(store: Store, zarr_format: ZarrFormat, consolidated_metad
         )
     )
 
-    # this warning shows up when extra objects show up in the hierarchy
-    warn_context = pytest.warns(
-        ZarrUserWarning,
-        match=r"(?:Object at .* is not recognized as a component of a Zarr hierarchy.)|(?:Consolidated metadata is currently not part in the Zarr format 3 specification.)",
-    )
     if consolidated_metadata:
+        consolidate_warn_context = (
+            pytest.warns(
+                ZarrUserWarning,
+                match="Consolidated metadata is currently not part in the Zarr format 3 specification.",
+            )
+            if zarr_format == 3
+            else contextlib.nullcontext()
+        )
         if isinstance(store, ZipStore):
-            with warn_context:
+            with consolidate_warn_context:
                 with pytest.warns(UserWarning, match="Duplicate name: "):
                     zarr.consolidate_metadata(store=store, zarr_format=zarr_format)
         else:
-            with warn_context:
+            with consolidate_warn_context:
                 zarr.consolidate_metadata(store=store, zarr_format=zarr_format)
-        # now that we've consolidated the store, we shouldn't get the warnings from the unrecognized objects anymore
-        # we use a nullcontext to handle these cases
-        warn_context = contextlib.nullcontext()
         group = zarr.open_consolidated(store=store, zarr_format=zarr_format)
 
-    with warn_context:
+    # extra objects in the hierarchy are skipped without warning
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", ZarrUserWarning)
         members_observed = group.members()
     # members are not guaranteed to be ordered, so sort before comparing
     assert sorted(dict(members_observed)) == sorted(members_expected)
 
     # partial
-    with warn_context:
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", ZarrUserWarning)
         members_observed = group.members(max_depth=1)
     members_expected["subgroup/subsubgroup"] = subsubgroup
     # members are not guaranteed to be ordered, so sort before comparing
     assert sorted(dict(members_observed)) == sorted(members_expected)
 
     # total
-    with warn_context:
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", ZarrUserWarning)
         members_observed = group.members(max_depth=None)
     members_expected["subgroup/subsubgroup/subsubsubgroup"] = subsubsubgroup
     # members are not guaranteed to be ordered, so sort before comparing

tests/test_metadata/test_consolidated.py

@@ -747,8 +747,7 @@ async def test_use_consolidated_for_children_members(
         # Now according to the consolidated metadata, "a" has children ["b"]
         # but according to the unconsolidated metadata, "a" has children ["b", "c"]
         group = await zarr.api.asynchronous.open_group(store=memory_store, path="a")
-        with pytest.warns(ZarrUserWarning, match="Object at 'c' not found"):
-            result = sorted([x[0] async for x in group.members(max_depth=None)])
+        result = sorted([x[0] async for x in group.members(max_depth=None)])
         expected = ["b"]
         assert result == expected