Added Ruff linter to replace black, flake8 and isort.

Includes Ruff autofixes:
 - 11 × D212 (multi-line-summary-first-line)
 - 1 × RET506 (superfluous-else-raise)
 - 1 × RET505 (superfluous-else-return)
 - 1 × I001 (unsorted-imports)
Added `PLR5501` to exclude list to preserve readability of TODO
block in convert method

.pre-commit-config.yaml

@@ -64,25 +64,11 @@ repos:
         types_or: [asciidoc, python, markdown, rst]
         additional_dependencies: [tomli]
 
-# TODO: To be replaced by Ruff:
--   repo: https://github.com/psf/black
-    rev: '24.10.0'
+-   repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: "v0.7.4"
     hooks:
-    -   id: black
+    -   id: ruff
         types: [file, python]
-        args: [--config=./pyproject.toml, .]
-
-# TODO: To be replaced by Ruff:
--   repo: https://github.com/PyCQA/flake8
-    rev: '7.1.1'
-    hooks:
-    -   id: flake8
-        types: [file, python]
-        args: [--config=./.flake8]
-
--   repo: https://github.com/pycqa/isort
-    rev: '5.13.2'
-    hooks:
-    -   id: isort
-        types: [file, python]
-        args: ["--profile", "black", "--filter-files"]
+        args: [--fix, --show-fixes]
+    -   id: ruff-format
+        types: [file, python]

pyproject.toml

@@ -64,18 +64,6 @@ test = {file = "requirements/pypi-optional-test.txt"}
 include = ["nc_time_axis*"]
 where = ["src"]
 
-[tool.black]
-line-length = 79
-target-version = ['py39', 'py310', 'py311']
-include = '\.pyi?$'
-
-[tool.isort]
-known_first_party = "nc_time_axis"
-line_length = 79
-profile = "black"
-skip_gitignore = "True"
-verbose = "False"
-
 [tool.pytest.ini_options]
 addopts = "-ra -v --doctest-modules"
 doctest_optionflags = "NORMALIZE_WHITESPACE ELLIPSIS NUMBER"
@@ -94,3 +82,45 @@ ignore = [
 [tool.codespell]
 ignore-words-list = "assertIn"
 skip = ".git,./docs/_build"
+
+[tool.ruff]
+line-length = 88
+
+[tool.ruff.format]
+preview = false
+
+[tool.ruff.lint]
+ignore = [
+    # flake8-commas (COM)
+    # https://docs.astral.sh/ruff/rules/#flake8-commas-com
+    "COM812",  # Trailing comma missing.
+    "COM819",  # Trailing comma prohibited.
+
+    # flake8-implicit-str-concat (ISC)
+    # https://docs.astral.sh/ruff/rules/single-line-implicit-string-concatenation/
+    # NOTE: This rule may cause conflicts when used with "ruff format".
+    "ISC001",  # Implicitly concatenate string literals on one line.
+
+    # TODO: exceptions that still need investigating are below.
+    # Might be fixable, or might become permanent (above):
+    "PLR5501" # collapsible-else-if; Preserve readability of TODO block in
+              # `convert` method
+]
+
+preview = false
+select = [
+    "ALL",
+    # list specific rules to include that is skipped using numpy convention.
+    "D212",  # Multi-line docstring summary should start at the first line
+]
+
+[tool.ruff.lint.isort]
+force-sort-within-sections = true
+# Change to match specific package name:
+known-first-party = ["nc_time_axis"]
+
+[tool.ruff.lint.per-file-ignores]
+# All test scripts
+
+[tool.ruff.lint.pydocstyle]
+convention = "numpy"

src/nc_time_axis/__init__.py

@@ -1,5 +1,4 @@
-"""
-Support for cftime axis in matplotlib.
+"""Support for cftime axis in matplotlib.
 
 """
 
@@ -110,8 +109,8 @@
 # Licensee agrees to be bound by the terms and conditions of this License
 # Agreement.
 
-import warnings
 from numbers import Number
+import warnings
 
 import cftime
 import matplotlib.dates as mdates
@@ -128,8 +127,7 @@
 
 
 class CalendarDateTime:
-    """
-    Container for a :py:class:`cftime.datetime` object and calendar.
+    """Container for a :py:class:`cftime.datetime` object and calendar.
 
     Parameters
     ----------
@@ -185,8 +183,7 @@ def __repr__(self):
 
 
 class AutoCFTimeFormatter(mticker.Formatter):
-    """
-    Automatic formatter for :py:class:`cftime.datetime` data.
+    """Automatic formatter for :py:class:`cftime.datetime` data.
 
     Automatically chooses a date format based on the resolution set by the
     :py:class:`NetCDFDateTimeLocator`.  If no resolution is set, a default
@@ -240,8 +237,7 @@ def __init__(self, *args, **kwargs):
 
 
 class CFTimeFormatter(mticker.Formatter):
-    """
-    A formatter for explicitly setting the format of a
+    """A formatter for explicitly setting the format of a
     :py:class:`cftime.datetime` axis.
 
     Parameters
@@ -266,8 +262,7 @@ def __call__(self, x, pos=0):
 
 
 class NetCDFTimeDateLocator(mticker.Locator):
-    """
-    Determines tick locations when plotting :py:class:`cftime.datetime` data.
+    """Determines tick locations when plotting :py:class:`cftime.datetime` data.
 
     Parameters
     ----------
@@ -322,8 +317,7 @@ def __init__(self, max_n_ticks, calendar, date_unit=None, min_n_ticks=3):
         self._cached_resolution = {}
 
     def compute_resolution(self, num1, num2, date1, date2):
-        """
-        Returns the resolution of the dates (hourly, minutely, yearly), and
+        """Returns the resolution of the dates (hourly, minutely, yearly), and
         an **approximate** number of those units.
 
         """
@@ -455,17 +449,15 @@ def has_year_zero(year):
 
 
 class NetCDFTimeConverter(mdates.DateConverter):
-    """
-    Converter for :py:class:`cftime.datetime` data.
+    """Converter for :py:class:`cftime.datetime` data.
 
     """
 
     standard_unit = "days since 2000-01-01"
 
     @staticmethod
     def axisinfo(unit, axis):
-        """
-        Returns the :class:`~matplotlib.units.AxisInfo` for *unit*.
+        """Returns the :class:`~matplotlib.units.AxisInfo` for *unit*.
 
         *unit* is a tzinfo instance or None.
         The *axis* argument is required but not used.
@@ -493,8 +485,7 @@ def axisinfo(unit, axis):
 
     @classmethod
     def default_units(cls, sample_point, axis):
-        """
-        Computes some units for the given data point.
+        """Computes some units for the given data point.
 
         """
         if hasattr(sample_point, "__iter__"):
@@ -514,8 +505,7 @@ def default_units(cls, sample_point, axis):
                     "Expecting cftimes with an extra " '"calendar" attribute.'
                 )
                 raise ValueError(msg)
-            else:
-                calendar = sample_point.calendar
+            calendar = sample_point.calendar
             date_type = type(sample_point)
         if calendar == "":
             raise ValueError(
@@ -525,8 +515,7 @@ def default_units(cls, sample_point, axis):
 
     @classmethod
     def convert(cls, value, unit, axis):
-        """
-        Converts value, if it is not already a number or sequence of numbers,
+        """Converts value, if it is not already a number or sequence of numbers,
         with :py:func:`cftime.date2num`.
 
         """
@@ -546,7 +535,7 @@ def convert(cls, value, unit, axis):
             if is_numlike(value):
                 return value
             # Not an array but a list of non-numerical types (thus assuming datetime types)
-            elif isinstance(value, (list, tuple)):
+            if isinstance(value, (list, tuple)):
                 first_value = value[0]
             else:
                 # Neither numerical, list or ndarray : must be a datetime scalar.
@@ -584,8 +573,7 @@ def convert(cls, value, unit, axis):
 
 
 def is_numlike(x):
-    """
-    The Matplotlib datalim, autoscaling, locators etc work with scalars which
+    """The Matplotlib datalim, autoscaling, locators etc work with scalars which
     are the units converted to floats given the current unit.  The converter may
     be passed these floats, or arrays of them, even when units are set.
 

src/nc_time_axis/tests/unit/test_AutoCFTimeFormatter.py

@@ -1,7 +1,7 @@
 """Unit tests for the `nc_time_axis.AutoCFTimeFormatter` class."""
 
 import unittest
-import unittest.mock as mock
+from unittest import mock
 
 import pytest