Ruff: smaller steps

.pre-commit-config.yaml

@@ -18,29 +18,18 @@ repos:
         # Don't commit to main branch.
     -   id: no-commit-to-branch
 
--   repo: https://github.com/psf/black
-    rev: 24.4.0
-    hooks:
-    -   id: black
-        types: [file, python]
-        args: [--config=./pyproject.toml]
-
--   repo: https://github.com/PyCQA/flake8
-    rev: 7.0.0
-    hooks:
-    -   id: flake8
-        types: [file, python]
-        args: [--config=./setup.cfg]
-
--   repo: https://github.com/PyCQA/isort
-    rev: 5.13.2
-    hooks:
-    -   id: isort
-        types: [file, python]
-        args: [--filter-files]
-
 -   repo: https://github.com/aio-libs/sort-all
     rev: v1.2.0
     hooks:
     -   id: sort-all
         types: [file, python]
+
+-   repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: "v0.1.5"
+    hooks:
+    # Run the linter
+    -   id: ruff
+        types: [file, python]
+        args: [--fix]
+    # Run the formatter.
+    -   id: ruff-format

cf_units/__init__.py

@@ -191,8 +191,8 @@ def suppress_errors():
         except _ud.UdunitsError as e:
             error_msg = ': "%s"' % e.error_msg() if e.errnum else ""
             raise OSError(
-                "[%s] Failed to open UDUNITS-2 XML unit database%s"
-                % (e.status_msg(), error_msg)
+                f"[{e.status_msg()}] "
+                f"Failed to open UDUNITS-2 XML unit database{error_msg}"
             )
 
 
@@ -566,11 +566,9 @@ def _ud_value_error(ud_err, message):
 
     ud_msg = ud_err.error_msg()
     if ud_msg:
-        message = "{}: {}".format(message, ud_msg)
+        message = f"{message}: {ud_msg}"
 
-    message = "[{status}] {message}".format(
-        status=ud_err.status_msg(), message=message
-    )
+    message = f"[{ud_err.status_msg()}] {message}"
 
     return ValueError(message)
 
@@ -727,7 +725,7 @@ def __init__(self, unit, calendar=None):
                 ut_unit = _ud.parse(_ud_system, unit.encode("utf8"), encoding)
             except _ud.UdunitsError as exception:
                 value_error = _ud_value_error(
-                    exception, 'Failed to parse unit "{}"'.format(str_unit)
+                    exception, f'Failed to parse unit "{str_unit}"'
                 )
                 raise value_error from None
             if _OP_SINCE in unit.lower():
@@ -932,7 +930,7 @@ def title(self, value):
             dt = self.num2date(value)
             result = dt.strftime("%Y-%m-%d %H:%M:%S")
         else:
-            result = "%s %s" % (str(value), self)
+            result = f"{value} {self}"
         return result
 
     @property
@@ -1222,13 +1220,13 @@ def offset_by_time(self, origin):
 
         if not isinstance(origin, (float, (int,))):
             raise TypeError(
-                "a numeric type for the origin argument is" " required"
+                "a numeric type for the origin argument is required"
             )
         try:
             ut_unit = _ud.offset_by_time(self.ut_unit, origin)
         except _ud.UdunitsError as exception:
             value_error = _ud_value_error(
-                exception, "Failed to offset {!r}".format(self)
+                exception, f"Failed to offset {self!r}"
             )
             raise value_error from None
         calendar = None
@@ -1300,7 +1298,7 @@ def root(self, root):
                 except _ud.UdunitsError as exception:
                     value_error = _ud_value_error(
                         exception,
-                        "Failed to take the root of {!r}".format(self),
+                        f"Failed to take the root of {self!r}",
                     )
                     raise value_error from None
                 calendar = None
@@ -1338,13 +1336,12 @@ def log(self, base):
                 ut_unit = _ud.log(base, self.ut_unit)
             except TypeError:
                 raise TypeError(
-                    "A numeric type for the base argument is " " required"
+                    "A numeric type for the base argument is required"
                 )
             except _ud.UdunitsError as exception:
                 value_err = _ud_value_error(
                     exception,
-                    "Failed to calculate logorithmic base "
-                    "of {!r}".format(self),
+                    f"Failed to calculate logorithmic base of {self!r}",
                 )
                 raise value_err from None
             calendar = None
@@ -1386,7 +1383,7 @@ def __repr__(self):
 
         """
         if self.calendar is None:
-            result = "{}('{}')".format(self.__class__.__name__, self)
+            result = f"{self.__class__.__name__}('{self}')"
         else:
             result = "{}('{}', calendar='{}')".format(
                 self.__class__.__name__, self, self.calendar
@@ -1440,7 +1437,7 @@ def _op_common(self, other, op_func):
             except _ud.UdunitsError as exception:
                 value_err = _ud_value_error(
                     exception,
-                    "Failed to {} {!r} by {!r}".format(op_label, self, other),
+                    f"Failed to {op_label} {self!r} by {other!r}",
                 )
                 raise value_err from None
             calendar = None
@@ -1595,7 +1592,7 @@ def __pow__(self, power):
                 except _ud.UdunitsError as exception:
                     value_err = _ud_value_error(
                         exception,
-                        "Failed to raise the power of {!r}".format(self),
+                        f"Failed to raise the power of {self!r}",
                     )
                     raise value_err from None
                 result = Unit._new_from_existing_ut(_CATEGORY_UDUNIT, ut_unit)
@@ -1674,7 +1671,7 @@ def change_calendar(self, calendar):
             >>> u.change_calendar('standard')
             Unit('days since 1499-12-23T00:00:00', calendar='standard')
 
-        """
+        """  # NOQA E501
         if not self.is_time_reference():
             raise ValueError("unit is not a time reference")
 
@@ -1772,7 +1769,7 @@ def convert(self, value, other, ctype=FLOAT64, inplace=False):
                 except _ud.UdunitsError as exception:
                     value_err = _ud_value_error(
                         exception,
-                        "Failed to convert {!r} to {!r}".format(self, other),
+                        f"Failed to convert {self!r} to {other!r}",
                     )
                     raise value_err from None
                 if isinstance(result, np.ndarray):
@@ -1796,9 +1793,8 @@ def convert(self, value, other, ctype=FLOAT64, inplace=False):
                     # Strict type check of numpy array.
                     if result.dtype.type not in (np.float32, np.float64):
                         raise TypeError(
-                            "Expect a numpy array of '%s' or '%s'"
-                            % np.float32,
-                            np.float64,
+                            "Expect a numpy array of "
+                            f"'{np.float32}' or '{np.float64}'"
                         )
                     ctype = result.dtype.type
                     # Utilise global convenience dictionary
@@ -1830,7 +1826,7 @@ def convert(self, value, other, ctype=FLOAT64, inplace=False):
             return result
         else:
             raise ValueError(
-                "Unable to convert from '%r' to '%r'." % (self, other)
+                f"Unable to convert from '{self!r}' to '{other!r}'."
             )
 
     @property

cf_units/_udunits2_parser/__init__.py

@@ -169,7 +169,7 @@ def __init__(self, unit_string):
 
     def syntaxError(self, recognizer, offendingSymbol, line, column, msg, e):
         # https://stackoverflow.com/a/36367357/741316
-        context = ("inline", line, column + 2, "'{}'".format(self.unit_string))
+        context = ("inline", line, column + 2, f"'{self.unit_string}'")
         syntax_error = SyntaxError(msg, context)
         raise syntax_error from None
 
@@ -192,7 +192,7 @@ def _debug_tokens(unit_string):
             continue
         token_type_idx = token.type
         rule = TOKEN_ID_NAMES[token_type_idx]
-        print("%s: %s" % (token.text, rule))
+        print(f"{token.text}: {rule}")
 
 
 def normalize(unit_string):

cf_units/_udunits2_parser/compile.py

@@ -41,7 +41,7 @@ def expand_lexer(source, target):
     MODE_P = re.compile(r"mode ([A-Z_]+)\;")
     TOKEN_P = re.compile(r"([A-Z_]+) ?\:.*")
 
-    with open(source, "r") as fh:
+    with open(source) as fh:
         content = fh.read()
 
     template = jinja2.Environment(loader=jinja2.BaseLoader).from_string(

cf_units/_udunits2_parser/graph.py

@@ -28,9 +28,9 @@ def __getattr__(self, name):
     def _repr_ctx(self):
         # Return a dictionary that is useful for passing to string.format.
         kwargs = ", ".join(
-            "{}={!r}".format(key, value) for key, value in self._attrs.items()
+            f"{key}={value!r}" for key, value in self._attrs.items()
         )
-        return dict(cls_name=self.__class__.__name__, kwargs=kwargs)
+        return {"cls_name": self.__class__.__name__, "kwargs": kwargs}
 
     def __repr__(self):
         return "{cls_name}({kwargs})".format(**self._repr_ctx())
@@ -49,7 +49,7 @@ def children(self):
         return []
 
     def __str__(self):
-        return "{}".format(self.content)
+        return f"{self.content}"
 
 
 class Operand(Terminal):

cf_units/_udunits2_parser/parser/udunits2Lexer.py

@@ -1,6 +1,6 @@
-# Generated from /home/ruth/git_stuff/cf-units/cf_units/_udunits2_parser/parser/udunits2Lexer.g4 by ANTLR 4.11.1
+# Generated from cf_units/_udunits2_parser/parser/udunits2Lexer.g4 by
+# ANTLR 4.11.1
 import sys
-from io import StringIO
 
 from antlr4 import *
 

cf_units/_udunits2_parser/parser/udunits2Parser.py

@@ -1,7 +1,5 @@
-# Generated from /home/ruth/git_stuff/cf-units/cf_units/_udunits2_parser/udunits2Parser.g4 by ANTLR 4.11.1
-# encoding: utf-8
+# Generated from cf_units/_udunits2_parser/udunits2Parser.g4 by ANTLR 4.11.1
 import sys
-from io import StringIO
 
 from antlr4 import *
 
@@ -2225,8 +2223,8 @@ def timezone_offset(self):
         return localctx
 
     def sempred(self, localctx: RuleContext, ruleIndex: int, predIndex: int):
-        if self._predicates == None:
-            self._predicates = dict()
+        if self._predicates is None:
+            self._predicates = {}
         self._predicates[2] = self.product_sempred
         pred = self._predicates.get(ruleIndex, None)
         if pred is None:

cf_units/_udunits2_parser/parser/udunits2ParserVisitor.py

@@ -1,4 +1,4 @@
-# Generated from /home/ruth/git_stuff/cf-units/cf_units/_udunits2_parser/udunits2Parser.g4 by ANTLR 4.11.1
+# Generated from cf_units/_udunits2_parser/udunits2Parser.g4 by ANTLR 4.11.1
 from antlr4 import *
 
 if __name__ is not None and "." in __name__:

cf_units/tests/integration/parse/test_parse.py

@@ -169,7 +169,7 @@ def test_invalid_units(_, unit_str):
     # Double check that udunits2 can't parse this.
     assert (
         cf_valid is False
-    ), "Unit {!r} is unexpectedly valid in UDUNITS2".format(unit_str)
+    ), f"Unit {unit_str!r} is unexpectedly valid in UDUNITS2"
 
     try:
         normalize(unit_str)
@@ -178,7 +178,7 @@ def test_invalid_units(_, unit_str):
         can_parse = False
 
     # Now confirm that we couldn't parse this either.
-    msg = "Parser unexpectedly able to deal with {}".format(unit_str)
+    msg = f"Parser unexpectedly able to deal with {unit_str}"
     assert can_parse is False, msg
 
 
@@ -242,7 +242,7 @@ def test_known_issues(_, unit_str, expected):
     # These are the cases that don't work yet but which do work with udunits.
 
     # Make sure udunits can read it.
-    cf_units.Unit(unit_str).symbol
+    _ = cf_units.Unit(unit_str).symbol
 
     if isinstance(expected, type) and issubclass(expected, Exception):
         with pytest.raises(SyntaxError):
@@ -293,7 +293,7 @@ def test_invalid_syntax_units(_, unit_str):
     # allowed with our grammar.
 
     with pytest.raises(ValueError):
-        cf_units.Unit(unit_str).symbol
+        _ = cf_units.Unit(unit_str).symbol
 
     with pytest.raises(SyntaxError):
         normalize(unit_str)

cf_units/tests/integration/test__Unit_num2date.py

@@ -186,7 +186,8 @@ def test_simple_360_day(self):
             self.udays,
             self.udays,
         ]
-        # Expected results in (days, seconds, microseconds) delta from unit epoch.
+        # Expected results in (days, seconds, microseconds) delta from unit
+        # epoch.
         expected = [
             (0, nums[0], 0),
             (0, nums[1], 0),
@@ -218,7 +219,8 @@ def test_fractional_360_day(self):
             self.udays,
             self.udays,
         ]
-        # Expected results in (days, seconds, microseconds) delta from unit epoch.
+        # Expected results in (days, seconds, microseconds) delta from unit
+        # epoch.
         expected = [
             (0, nums[0] * 60, 0),
             (0, nums[1] * 60, 0),
@@ -234,7 +236,8 @@ def test_fractional_second_360_day(self):
         self.setup_units("360_day")
         nums = [0.25, 0.5, 0.75, 1.5, 2.5, 3.5, 4.5]
         units = [self.useconds] * 7
-        # Expected results in (days, seconds, microseconds) delta from unit epoch.
+        # Expected results in (days, seconds, microseconds) delta from unit
+        # epoch.
         expected = [
             (0, 0, 250000),
             (0, 0, 500000),
@@ -273,7 +276,8 @@ def test_simple_365_day(self):
             self.udays,
             self.udays,
         ]
-        # Expected results in (days, seconds, microseconds) delta from unit epoch.
+        # Expected results in (days, seconds, microseconds) delta from unit
+        # epoch.
         expected = [
             (0, nums[0], 0),
             (0, nums[1], 0),
@@ -305,7 +309,8 @@ def test_fractional_365_day(self):
             self.udays,
             self.udays,
         ]
-        # Expected results in (days, seconds, microseconds) delta from unit epoch.
+        # Expected results in (days, seconds, microseconds) delta from unit
+        # epoch.
         expected = [
             (0, nums[0] * 60, 0),
             (0, nums[1] * 60, 0),
@@ -321,7 +326,8 @@ def test_fractional_second_365_day(self):
         self.setup_units("365_day")
         nums = [0.25, 0.5, 0.75, 1.5, 2.5, 3.5, 4.5]
         units = [self.useconds] * 7
-        # Expected results in (days, seconds, microseconds) delta from unit epoch.
+        # Expected results in (days, seconds, microseconds) delta from unit
+        # epoch.
         expected = [
             (0, 0, 250000),
             (0, 0, 500000),

cf_units/tests/test_coding_standards.py

@@ -75,7 +75,7 @@ def last_change_by_fname():
         """
         # Check the ".git" folder exists at the repo dir.
         if not os.path.isdir(os.path.join(REPO_DIR, ".git")):
-            raise ValueError("{} is not a git repository.".format(REPO_DIR))
+            raise ValueError(f"{REPO_DIR} is not a git repository.")
 
         # Call "git whatchanged" to get the details of all the files and when
         # they were last changed.
@@ -109,7 +109,7 @@ def test_license_headers(self):
             )
 
         failed = False
-        for fname, last_change in sorted(last_change_by_fname.items()):
+        for fname in sorted(last_change_by_fname):
             full_fname = os.path.join(REPO_DIR, fname)
             if (
                 full_fname.endswith(".py")

cf_units/tests/test_unit.py

@@ -833,7 +833,7 @@ def test_time_unit(self):
 class Test__immutable:
     def _set_attr(self, unit, name):
         setattr(unit, name, -999)
-        raise ValueError("'Unit' attribute {!r} is mutable!".format(name))
+        raise ValueError(f"'Unit' attribute {name!r} is mutable!")
 
     def test_immutable(self):
         u = Unit("m")