Enforce Pylint rules

.github/workflows/test.yml

@@ -153,3 +153,20 @@ jobs:
         run: exit 1
       - name: Success
         run: echo Success!
+
+  pylint:
+    name: Pylint
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v5
+    - name: Set up Python
+      uses: actions/setup-python@v6
+      with:
+        python-version: '3.*'
+    - name: Install Pylint
+      run: |
+        python -m pip install --upgrade pip
+        pip install pylint
+    - name: Analyse the code with Pylint
+      run: |
+        pylint .

pyproject.toml

@@ -452,3 +452,57 @@ ignore-words-list = "astroid"
 
 [project.entry-points.pytest11]
 zarr = "zarr.testing"
+
+[tool.pylint]
+disable = [
+    "E0401", # import-error
+    "E0606", # possibly-used-before-assignment  # FIXME
+    "E1123", # unexpected-keyword-arg  # FIXME
+    "E1125", # missing-kwoa  # FIXME
+    "E1136", # unsubscriptable-object
+    "W0104", # pointless-statement
+    "W0105", # pointless-string-statement
+    "W0106", # expression-not-assigned
+    "W0212", # protected-access
+    "W0223", # abstract-method  # FIXME
+    "W0246", # useless-parent-delegation  # FIXME
+    "W0511", # fixme
+    "W0602", # global-variable-not-assigned
+    "W0603", # global-statement
+    "W0611", # unused-import  # FIXME
+    "W0613", # unused-argument
+    "W0621", # redefined-outer-name
+    "W0622", # redefined-builtin
+    "W0718", # broad-exception-caught
+    "W1510", # subprocess-run-check
+    "C0103", # invalid-name
+    "C0104", # disallowed-name
+    "C0105", # typevar-name-incorrect-variance
+    "C0114", # missing-module-docstring
+    "C0115", # missing-class-docstring
+    "C0116", # missing-function-docstring
+    "C0123", # unidiomatic-typecheck
+    "C0301", # line-too-long
+    "C0302", # too-many-lines
+    "C0411", # wrong-import-order
+    "C0412", # ungrouped-imports
+    "C0413", # wrong-import-position
+    "C0415", # import-outside-toplevel
+    "C1803", # use-implicit-booleaness-not-comparison
+    "R0124", # comparison-with-itself
+    "R0801", # duplicate-code
+    "R0902", # too-many-instance-attributes
+    "R0903", # too-few-public-methods
+    "R0904", # too-many-public-methods
+    "R0911", # too-many-return-statements
+    "R0912", # too-many-branches
+    "R0913", # too-many-arguments
+    "R0914", # too-many-locals
+    "R0915", # too-many-statements
+    "R0917", # too-many-positional-arguments
+    "R1702", # too-many-nested-blocks
+    "R1705", # no-else-return
+    "R1720", # no-else-raise
+    "R1728", # consider-using-generator
+    "R1732", # consider-using-with  # FIXME
+]

src/zarr/abc/codec.py

@@ -86,7 +86,6 @@ def compute_encoded_size(self, input_byte_length: int, chunk_spec: ArraySpec) ->
         -------
         int
         """
-        ...
 
     def resolve_metadata(self, chunk_spec: ArraySpec) -> ArraySpec:
         """Computed the spec of the chunk after it has been encoded by the codec.
@@ -289,7 +288,6 @@ def evolve_from_array_spec(self, array_spec: ArraySpec) -> Self:
         -------
         Self
         """
-        ...
 
     @classmethod
     @abstractmethod
@@ -304,7 +302,6 @@ def from_codecs(cls, codecs: Iterable[Codec]) -> Self:
         -------
         Self
         """
-        ...
 
     @classmethod
     def from_array_metadata_and_store(cls, array_metadata: ArrayMetadata, store: Store) -> Self:
@@ -353,7 +350,6 @@ def validate(
         chunk_grid : ChunkGrid
             The array chunk grid
         """
-        ...
 
     @abstractmethod
     def compute_encoded_size(self, byte_length: int, array_spec: ArraySpec) -> int:
@@ -369,7 +365,6 @@ def compute_encoded_size(self, byte_length: int, array_spec: ArraySpec) -> int:
         -------
         int
         """
-        ...
 
     @abstractmethod
     async def decode(
@@ -388,7 +383,6 @@ async def decode(
         -------
         Iterable[NDBuffer | None]
         """
-        ...
 
     @abstractmethod
     async def encode(
@@ -407,7 +401,6 @@ async def encode(
         -------
         Iterable[Buffer | None]
         """
-        ...
 
     @abstractmethod
     async def read(
@@ -434,7 +427,6 @@ async def read(
 
         out : NDBuffer
         """
-        ...
 
     @abstractmethod
     async def write(
@@ -457,7 +449,6 @@ async def write(
             The chunk spec contains information about the chunk.
         value : NDBuffer
         """
-        ...
 
 
 async def _batching_helper(

src/zarr/abc/numcodec.py

@@ -26,7 +26,6 @@ def encode(self, buf: Any) -> Any:
         enc: Any
             Encoded data.
         """
-        ...
 
     def decode(self, buf: Any, out: Any | None = None) -> Any:
         """
@@ -45,14 +44,12 @@ def decode(self, buf: Any, out: Any | None = None) -> Any:
         dec : Any
             Decoded data.
         """
-        ...
 
     def get_config(self) -> Any:
         """
         Return a JSON-serializable configuration dictionary for this
         codec. Must include an ``'id'`` field with the codec identifier.
         """
-        ...
 
     @classmethod
     def from_config(cls, config: Any) -> Self:
@@ -64,7 +61,6 @@ def from_config(cls, config: Any) -> Self:
         config : Any
             A configuration dictionary for this codec.
         """
-        ...
 
 
 def _is_numcodec_cls(obj: object) -> TypeGuard[type[Numcodec]]:

src/zarr/abc/store.py

@@ -178,7 +178,6 @@ def _check_writable(self) -> None:
     @abstractmethod
     def __eq__(self, value: object) -> bool:
         """Equality comparison."""
-        ...
 
     @abstractmethod
     async def get(
@@ -204,7 +203,6 @@ async def get(
         -------
         Buffer
         """
-        ...
 
     @abstractmethod
     async def get_partial_values(
@@ -225,7 +223,6 @@ async def get_partial_values(
         -------
         list of values, in the order of the key_ranges, may contain null/none for missing keys
         """
-        ...
 
     @abstractmethod
     async def exists(self, key: str) -> bool:
@@ -239,13 +236,11 @@ async def exists(self, key: str) -> bool:
         -------
         bool
         """
-        ...
 
     @property
     @abstractmethod
     def supports_writes(self) -> bool:
         """Does the store support writes?"""
-        ...
 
     @abstractmethod
     async def set(self, key: str, value: Buffer) -> None:
@@ -256,7 +251,6 @@ async def set(self, key: str, value: Buffer) -> None:
         key : str
         value : Buffer
         """
-        ...
 
     async def set_if_not_exists(self, key: str, value: Buffer) -> None:
         """
@@ -296,7 +290,6 @@ def supports_consolidated_metadata(self) -> bool:
     @abstractmethod
     def supports_deletes(self) -> bool:
         """Does the store support deletes?"""
-        ...
 
     @abstractmethod
     async def delete(self, key: str) -> None:
@@ -306,7 +299,6 @@ async def delete(self, key: str) -> None:
         ----------
         key : str
         """
-        ...
 
     @property
     def supports_partial_writes(self) -> Literal[False]:
@@ -320,7 +312,6 @@ def supports_partial_writes(self) -> Literal[False]:
     @abstractmethod
     def supports_listing(self) -> bool:
         """Does the store support listing?"""
-        ...
 
     @abstractmethod
     def list(self) -> AsyncIterator[str]:

src/zarr/codecs/numcodecs/_codecs.py

@@ -137,9 +137,6 @@ def __repr__(self) -> str:
 
 
 class _NumcodecsBytesBytesCodec(_NumcodecsCodec, BytesBytesCodec):
-    def __init__(self, **codec_config: JSON) -> None:
-        super().__init__(**codec_config)
-
     async def _decode_single(self, chunk_data: Buffer, chunk_spec: ArraySpec) -> Buffer:
         return await asyncio.to_thread(
             as_numpy_array_wrapper,
@@ -159,9 +156,6 @@ async def _encode_single(self, chunk_data: Buffer, chunk_spec: ArraySpec) -> Buf
 
 
 class _NumcodecsArrayArrayCodec(_NumcodecsCodec, ArrayArrayCodec):
-    def __init__(self, **codec_config: JSON) -> None:
-        super().__init__(**codec_config)
-
     async def _decode_single(self, chunk_data: NDBuffer, chunk_spec: ArraySpec) -> NDBuffer:
         chunk_ndarray = chunk_data.as_ndarray_like()
         out = await asyncio.to_thread(self._codec.decode, chunk_ndarray)
@@ -174,9 +168,6 @@ async def _encode_single(self, chunk_data: NDBuffer, chunk_spec: ArraySpec) -> N
 
 
 class _NumcodecsArrayBytesCodec(_NumcodecsCodec, ArrayBytesCodec):
-    def __init__(self, **codec_config: JSON) -> None:
-        super().__init__(**codec_config)
-
     async def _decode_single(self, chunk_data: Buffer, chunk_spec: ArraySpec) -> NDBuffer:
         chunk_bytes = chunk_data.to_bytes()
         out = await asyncio.to_thread(self._codec.decode, chunk_bytes)
@@ -253,9 +244,6 @@ def evolve_from_array_spec(self, array_spec: ArraySpec) -> FixedScaleOffset:
 
 
 class Quantize(_NumcodecsArrayArrayCodec, codec_name="quantize"):
-    def __init__(self, **codec_config: JSON) -> None:
-        super().__init__(**codec_config)
-
     def evolve_from_array_spec(self, array_spec: ArraySpec) -> Quantize:
         if self.codec_config.get("dtype") is None:
             dtype = array_spec.dtype.to_native_dtype()

src/zarr/core/buffer/core.py

@@ -253,7 +253,6 @@ def as_numpy_array(self) -> npt.NDArray[Any]:
         -------
             NumPy array of this buffer (might be a data copy)
         """
-        ...
 
     def as_buffer_like(self) -> BytesLike:
         """Returns the buffer as an object that implements the Python buffer protocol.
@@ -296,7 +295,6 @@ def __len__(self) -> int:
     @abstractmethod
     def __add__(self, other: Buffer) -> Self:
         """Concatenate two buffers"""
-        ...
 
     def __eq__(self, other: object) -> bool:
         # Another Buffer class can override this to choose a more efficient path
@@ -469,7 +467,6 @@ def as_numpy_array(self) -> npt.NDArray[Any]:
         -------
             NumPy array of this buffer (might be a data copy)
         """
-        ...
 
     def as_scalar(self) -> ScalarType:
         """Returns the buffer as a scalar value"""

src/zarr/core/dtype/common.py

@@ -80,7 +80,7 @@ def check_structured_dtype_v2_inner(data: object) -> TypeGuard[StructuredName_V2
         return False
     if len(data) != 2:
         return False
-    if not (isinstance(data[0], str)):
+    if not isinstance(data[0], str):
         return False
     if isinstance(data[-1], str):
         return True

src/zarr/core/group.py

@@ -3208,11 +3208,13 @@ async def create_hierarchy(
     nodes_parsed = _parse_hierarchy_dict(data=nodes_normed_keys)
     redundant_implicit_groups = []
 
-    # empty hierarchies should be a no-op
-    if len(nodes_parsed) > 0:
+    try:
         # figure out which zarr format we are using
         zarr_format = next(iter(nodes_parsed.values())).zarr_format
-
+    except StopIteration:
+        # empty hierarchies should be a no-op
+        pass
+    else:
         # check which implicit groups will require materialization
         implicit_group_keys = tuple(
             filter(lambda k: isinstance(nodes_parsed[k], ImplicitGroupMarker), nodes_parsed)

src/zarr/core/metadata/v2.py

@@ -265,11 +265,10 @@ def parse_filters(data: object) -> tuple[Numcodec, ...] | None:
     """
     Parse a potential tuple of filters
     """
-    out: list[Numcodec] = []
-
     if data is None:
         return data
     if isinstance(data, Iterable):
+        out: list[Numcodec] = []
         for idx, val in enumerate(data):
             if _is_numcodec(val):
                 out.append(val)

src/zarr/storage/_zip.py

@@ -84,6 +84,7 @@ def __init__(
         assert isinstance(path, Path)
         self.path = path  # root?
 
+        self._is_open = False
         self._zmode = mode
         self.compression = compression
         self.allowZip64 = allowZip64
@@ -123,6 +124,7 @@ def close(self) -> None:
         super().close()
         with self._lock:
             self._zf.close()
+        self._is_open = False
 
     async def clear(self) -> None:
         # docstring inherited

src/zarr/testing/stateful.py

@@ -161,7 +161,7 @@ def add_array(
     @with_frequency(0.25)
     def clear(self) -> None:
         note("clearing")
-        import zarr
+        import zarr  # pylint: disable=reimported
 
         self._sync(self.store.clear())
         self._sync(self.model.clear())