use ruff as linter (#3008)

.github/workflows/lint.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
   build:
     runs-on: ubuntu-latest
-    name: black-flake8-mypy
+    name: black-ruff-mypy
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python 3.10
@@ -21,9 +21,10 @@ jobs:
       run: |
         black --diff --color .
         black --check .
-    - name: Lint with flake8
-      run: |
-        flake8 .  --statistics
+    - name: Lint with ruff
+      run: |        
+        ruff check .
+
     - name: Lint with mypy
       run: |
         mypy altair tests

Makefile

@@ -5,7 +5,7 @@ install:
 
 test :
 	black --diff --color --check .
-	flake8 . --statistics
+	ruff check .
 	mypy altair tests
 	python -m pytest --pyargs --doctest-modules tests
 

altair/__init__.py

@@ -1,4 +1,4 @@
-# flake8: noqa
+# ruff: noqa
 __version__ = "5.0.0dev"
 
 from typing import Any

altair/_magics.py

@@ -44,7 +44,7 @@ def _prepare_data(data, data_transformers):
     elif isinstance(data, str):
         return {"url": data}
     else:
-        warnings.warn("data of type {} not recognized".format(type(data)))
+        warnings.warn("data of type {} not recognized".format(type(data)), stacklevel=1)
         return data
 
 
@@ -94,11 +94,11 @@ def vegalite(line, cell):
     elif not YAML_AVAILABLE:
         try:
             spec = json.loads(cell)
-        except json.JSONDecodeError:
+        except json.JSONDecodeError as err:
             raise ValueError(
                 "%%vegalite: spec is not valid JSON. "
                 "Install pyyaml to parse spec as yaml"
-            )
+            ) from err
     else:
         spec = yaml.load(cell, Loader=yaml.SafeLoader)
 

altair/expr/__init__.py

@@ -1,5 +1,5 @@
 """Tools for creating transform & filter expressions with a python syntax"""
-# flake8: noqa
+# ruff: noqa
 from typing import Any
 
 from .core import datum, Expression

altair/utils/core.py

@@ -227,7 +227,8 @@ def infer_vegalite_type(data):
     else:
         warnings.warn(
             "I don't know how to infer vegalite type from '{}'.  "
-            "Defaulting to nominal.".format(typ)
+            "Defaulting to nominal.".format(typ),
+            stacklevel=1,
         )
         return "nominal"
 
@@ -483,15 +484,15 @@ def parse_shorthand(
 
     valid_typecodes = list(TYPECODE_MAP) + list(INV_TYPECODE_MAP)
 
-    units = dict(
-        field="(?P<field>.*)",
-        type="(?P<type>{})".format("|".join(valid_typecodes)),
-        agg_count="(?P<aggregate>count)",
-        op_count="(?P<op>count)",
-        aggregate="(?P<aggregate>{})".format("|".join(AGGREGATES)),
-        window_op="(?P<op>{})".format("|".join(AGGREGATES + WINDOW_AGGREGATES)),
-        timeUnit="(?P<timeUnit>{})".format("|".join(TIMEUNITS)),
-    )
+    units = {
+        "field": "(?P<field>.*)",
+        "type": "(?P<type>{})".format("|".join(valid_typecodes)),
+        "agg_count": "(?P<aggregate>count)",
+        "op_count": "(?P<op>count)",
+        "aggregate": "(?P<aggregate>{})".format("|".join(AGGREGATES)),
+        "window_op": "(?P<op>{})".format("|".join(AGGREGATES + WINDOW_AGGREGATES)),
+        "timeUnit": "(?P<timeUnit>{})".format("|".join(TIMEUNITS)),
+    }
 
     patterns = []
 
@@ -710,7 +711,9 @@ def _wrap_in_channel_class(obj, encoding):
             return [_wrap_in_channel_class(subobj, encoding) for subobj in obj]
 
         if encoding not in name_to_channel:
-            warnings.warn("Unrecognized encoding channel '{}'".format(encoding))
+            warnings.warn(
+                "Unrecognized encoding channel '{}'".format(encoding), stacklevel=1
+            )
             return obj
 
         classes = name_to_channel[encoding]

altair/utils/data.py

@@ -258,6 +258,7 @@ def pipe(data, *funcs):
         "alt.pipe() is deprecated, and will be removed in a future release. "
         "Use toolz.curried.pipe() instead.",
         AltairDeprecationWarning,
+        stacklevel=1,
     )
     return curried.pipe(data, *funcs)
 
@@ -271,6 +272,7 @@ def curry(*args, **kwargs):
         "alt.curry() is deprecated, and will be removed in a future release. "
         "Use toolz.curried.curry() instead.",
         AltairDeprecationWarning,
+        stacklevel=1,
     )
     return curried.curry(*args, **kwargs)
 
@@ -284,14 +286,14 @@ def import_pyarrow_interchange():
         import pyarrow.interchange as pi
 
         return pi
-    except pkg_resources.DistributionNotFound:
+    except pkg_resources.DistributionNotFound as err:
         # The package is not installed
         raise ImportError(
             "Usage of the DataFrame Interchange Protocol requires the package 'pyarrow', but it is not installed."
-        )
-    except pkg_resources.VersionConflict:
+        ) from err
+    except pkg_resources.VersionConflict as err:
         # The package is installed but does not meet the minimum version requirement
         raise ImportError(
             "The installed version of 'pyarrow' does not meet the minimum requirement of version 11.0.0. "
             "Please update 'pyarrow' to use the DataFrame Interchange Protocol."
-        )
+        ) from err

altair/utils/deprecation.py

@@ -62,7 +62,7 @@ def _deprecate(obj, name=None, message=None):
 
         @functools.wraps(obj)
         def new_obj(*args, **kwargs):
-            warnings.warn(message, AltairDeprecationWarning)
+            warnings.warn(message, AltairDeprecationWarning, stacklevel=1)
             return obj(*args, **kwargs)
 
         new_obj._deprecated = True

altair/utils/html.py

@@ -251,14 +251,14 @@ def spec_to_html(
     if mode == "vega-lite" and vegalite_version is None:
         raise ValueError("must specify vega-lite version for mode='vega-lite'")
 
-    render_kwargs = dict()
+    render_kwargs = {}
     if template == "inline":
         try:
             from altair_viewer import get_bundled_script
-        except ImportError:
+        except ImportError as err:
             raise ImportError(
                 "The altair_viewer package is required to convert to HTML with inline=True"
-            )
+            ) from err
         render_kwargs["vega_script"] = get_bundled_script("vega", vega_version)
         render_kwargs["vegalite_script"] = get_bundled_script(
             "vega-lite", vegalite_version

altair/utils/plugin_registry.py

@@ -157,11 +157,11 @@ def _enable(self, name: str, **options) -> None:
                     for ep in importlib_metadata_get(self.entry_point_group)
                     if ep.name == name
                 ]
-            except ValueError:
+            except ValueError as err:
                 if name in self.entrypoint_err_messages:
-                    raise ValueError(self.entrypoint_err_messages[name])
+                    raise ValueError(self.entrypoint_err_messages[name]) from err
                 else:
-                    raise NoSuchEntryPoint(self.entry_point_group, name)
+                    raise NoSuchEntryPoint(self.entry_point_group, name) from err
             value = cast(PluginType, ep.load())
             self.register(name, value)
         self._active_name = name

altair/utils/save.py

@@ -30,7 +30,7 @@ def set_inspect_format_argument(format, fp, inline):
             )
 
     if format != "html" and inline:
-        warnings.warn("inline argument ignored for non HTML formats.")
+        warnings.warn("inline argument ignored for non HTML formats.", stacklevel=1)
 
     return format
 

altair/utils/schemapi.py

@@ -564,11 +564,22 @@ def to_dict(self, validate=True, ignore=None, context=None):
             try:
                 self.validate(result)
             except jsonschema.ValidationError as err:
-                raise SchemaValidationError(self, err)
+                # We do not raise `from err` as else the resulting
+                # traceback is very long as it contains part
+                # of the Vega-Lite schema. It would also first
+                # show the less helpful ValidationError instead of
+                # the more user friendly SchemaValidationError
+                raise SchemaValidationError(self, err) from None
         return result
 
     def to_json(
-        self, validate=True, ignore=[], context={}, indent=2, sort_keys=True, **kwargs
+        self,
+        validate=True,
+        ignore=None,
+        context=None,
+        indent=2,
+        sort_keys=True,
+        **kwargs,
     ):
         """Emit the JSON representation for this object as a string.
 
@@ -577,7 +588,7 @@ def to_json(
         validate : boolean
             If True (default), then validate the output dictionary
             against the schema.
-        ignore : list
+        ignore : list (optional)
             A list of keys to ignore. This will *not* passed to child to_dict
             function calls.
         context : dict (optional)
@@ -595,6 +606,10 @@ def to_json(
         spec : string
             The JSON specification of the chart object.
         """
+        if ignore is None:
+            ignore = []
+        if context is None:
+            context = {}
         dct = self.to_dict(validate=validate, ignore=ignore, context=context)
         return json.dumps(dct, indent=indent, sort_keys=sort_keys, **kwargs)
 

altair/vegalite/__init__.py

@@ -1,2 +1,2 @@
-# flake8: noqa
+# ruff: noqa
 from .v5 import *

altair/vegalite/api.py

@@ -1,2 +1,2 @@
-# flake8: noqa
+# ruff: noqa
 from .v5.api import *

altair/vegalite/schema.py

@@ -1,3 +1,3 @@
 """Altair schema wrappers"""
-# flake8: noqa
+# ruff: noqa
 from .v5.schema import *

altair/vegalite/v5/__init__.py

@@ -1,4 +1,4 @@
-# flake8: noqa
+# ruff: noqa
 from .schema import *
 from .api import *
 

altair/vegalite/v5/api.py

@@ -112,7 +112,7 @@ def _prepare_data(data, context=None):
 
     # if data is still not a recognized type, then return
     if not isinstance(data, (dict, core.Data)):
-        warnings.warn("data of type {} not recognized".format(type(data)))
+        warnings.warn("data of type {} not recognized".format(type(data)), stacklevel=1)
 
     return data
 
@@ -355,12 +355,14 @@ def param(
             warnings.warn(
                 """The value of 'empty' should be True or False.""",
                 utils.AltairDeprecationWarning,
+                stacklevel=1,
             )
             parameter.empty = False
         elif parameter.empty == "all":
             warnings.warn(
                 """The value of 'empty' should be True or False.""",
                 utils.AltairDeprecationWarning,
+                stacklevel=1,
             )
             parameter.empty = True
         elif (parameter.empty is False) or (parameter.empty is True):
@@ -372,6 +374,7 @@ def param(
         warnings.warn(
             """Use 'value' instead of 'init'.""",
             utils.AltairDeprecationWarning,
+            stacklevel=1,
         )
         if value is Undefined:
             kwds["value"] = kwds.pop("init")
@@ -416,6 +419,7 @@ def _selection(type=Undefined, **kwds):
             """The types 'single' and 'multi' are now
         combined and should be specified using "selection_point()".""",
             utils.AltairDeprecationWarning,
+            stacklevel=1,
         )
     else:
         raise ValueError("""'type' must be 'point' or 'interval'""")
@@ -2261,11 +2265,11 @@ def show(self, embed_opt=None, open_browser=None):
         """
         try:
             import altair_viewer  # type: ignore
-        except ImportError:
+        except ImportError as err:
             raise ValueError(
                 "'show' method requires the altair_viewer package. "
                 "See http://github.com/altair-viz/altair_viewer"
-            )
+            ) from err
         altair_viewer.show(self, embed_opt=embed_opt, open_browser=open_browser)
 
     @utils.use_signature(core.Resolve)

altair/vegalite/v5/schema/__init__.py

@@ -1,4 +1,4 @@
-# flake8: noqa
+# ruff: noqa
 from .core import *
 from .channels import *
 SCHEMA_VERSION = 'v5.6.1'

doc/releases/changes.rst

@@ -52,6 +52,11 @@ Backward-Incompatible Changes
 - Removed the Vega-Lite 3 and 4 wrappers (#2847).
 - In regards to the grammar changes listed above, the old terminology will still work in many basic cases.  On the other hand, if that old terminology gets used at a lower level, then it most likely will not work.  For example, in the current version of :ref:`gallery_scatter_with_minimap`, two instances of the key ``param`` are used in dictionaries to specify axis domains.  Those used to be ``selection``, but that usage is not compatible with the current Vega-Lite schema.
 
+Maintenance
+~~~~~~~~~~~
+
+- Vega-Altair now uses ``ruff`` for linting.
+
 Version 4.2.2 (released Jan 27, 2023)
 -------------------------------------
 

pyproject.toml

@@ -22,6 +22,37 @@ exclude = '''
 requires = ["setuptools >= 40.6.0, <64", "wheel"]
 build-backend = "setuptools.build_meta"
 
+[tool.ruff]
+target-version = "py310"
+line-length = 88
+select = [
+    # flake8-bugbear
+    "B",
+    # flake8-comprehensions
+    "C4",
+    # pycodestyle-error
+    "E",
+    # pycodestyle-warning
+    "W",
+    # pyflakes
+    "F",
+    # flake8-tidy-imports
+    "TID"
+]
+# ignore = ["E203", "E266", "E501", "W503"] see https://github.com/charliermarsh/ruff/issues/2402
+ignore = ["E501", "TID252", "B905"]
+exclude = [
+    ".git",
+    "build",
+    "__pycache__",
+    "tests/examples_arguments_syntax",
+    "tests/examples_methods_syntax",
+    "altair/vegalite/v?/schema",
+]
+
+[tool.ruff.mccabe]
+max-complexity = 18
+
 [tool.pytest.ini_options]
 markers = [
     "save_engine: marks some of the tests which are using an external package to save a chart to e.g. a png file. This mark is used to run those tests selectively in the build GitHub Action.",

requirements_dev.txt

@@ -1,6 +1,6 @@
 black<24
 ipython
-flake8
+ruff
 pytest
 pytest-cov
 m2r