Adds ruff format

diff_cover/diff_quality_tool.py

@@ -60,6 +60,7 @@
     pydocstyle_driver,
     pyflakes_driver,
     ruff_check_driver,
+    ruff_format_driver,
     shellcheck_driver,
 )
 
@@ -70,6 +71,7 @@
     "pyflakes": pyflakes_driver,
     "pylint": PylintDriver(),
     "ruff.check": ruff_check_driver,
+    "ruff.format": ruff_format_driver,
     "flake8": flake8_driver,
     "jshint": jshint_driver,
     "eslint": EslintDriver(),

diff_cover/report_generator.py

@@ -11,6 +11,7 @@
 
 from diff_cover.snippets import Snippet
 from diff_cover.util import to_unix_path
+from diff_cover.violationsreporters.base import Violation
 
 
 class DiffViolations:
@@ -19,9 +20,10 @@
     """
 
     def __init__(self, violations, measured_lines, diff_lines):
-        self.lines = {violation.line for violation in violations}.intersection(
-            diff_lines
-        )
+        _lines = {violation.line for violation in violations}
+        self.lines = _lines.intersection(diff_lines)
+        if Violation.ALL_LINES in _lines:
+            self.lines.add(Violation.ALL_LINES)
 
         self.violations = {
             violation for violation in violations if violation.line in self.lines
@@ -99,6 +101,9 @@
         if diff_violations is None:
             return None
 
+        if Violation.ALL_LINES in diff_violations.lines:
+            return 0
+
         # Protect against a divide by zero
         num_measured = len(diff_violations.measured_lines)
         if num_measured > 0:

diff_cover/util.py

@@ -88,3 +88,32 @@ def to_unescaped_filename(filename: str) -> str:
             i += 1
 
     return "".join(result)
+
+
+def merge_ranges(nums):
+    """
+    Merge a list of numbers into a list of ranges.
+    Given a list of numbers, merge consecutive numbers
+    into ranges of strings e.g. [1, 2, 3] -> ["1-3"]
+    """
+    if not nums:
+        return []
+    nums = sorted(set(nums))
+    ranges = []
+    start = prev = nums[0]
+
+    def add_range(start_, end_):
+        """Helper function to add a range to the list."""
+        if start_ == end_:
+            ranges.append(str(start_))
+        else:
+            ranges.append(f"{start_}-{end_}")
+
+    for n in nums[1:]:
+        if n == prev + 1:
+            prev = n
+            continue
+        add_range(start, prev)
+        start = prev = n
+    add_range(start, prev)
+    return ranges

diff_cover/violationsreporters/base.py

@@ -4,11 +4,41 @@
 import sys
 from abc import ABC, abstractmethod
 from collections import defaultdict, namedtuple
+from functools import lru_cache
 
 from diff_cover.command_runner import execute, run_command_for_code
 from diff_cover.util import to_unix_path
 
-Violation = namedtuple("Violation", "line, message")
+
+class Violation(namedtuple("_", "line, message")):
+    ALL_LINES = -1
+
+
+class SourceFile:
+    __slots__ = ("path", "violations")
+
+    def __init__(self, path):
+        self.path = path
+        self.violations = []
+
+    def add_violation(self, violation):
+        self.violations.add(violation)
+
+    @property
+    @lru_cache(maxsize=1)
+    def content(self):
+        with open(self.path, "r", encoding="utf-8") as f:
+            return f.read()
+
+    @property
+    @lru_cache(maxsize=1)
+    def size(self):
+        return len(self.content)
+
+    @property
+    @lru_cache(maxsize=1)
+    def lines(self):
+        return set(self.content.splitlines())
 
 
 class QualityReporterError(Exception):
@@ -228,20 +258,25 @@
         violations_dict = defaultdict(list)
         for report in reports:
             if self.expression.flags & re.MULTILINE:
-                matches = (match for match in re.finditer(self.expression, report))
+                matches = re.finditer(self.expression, report)
             else:
                 matches = (
                     self.expression.match(line.rstrip()) for line in report.split("\n")
                 )
             for match in matches:
-                if match is not None:
-                    src, line_number, message = match.groups()
-                    # Transform src to a relative path, if it isn't already
-                    src = to_unix_path(os.path.relpath(src))
-                    violation = Violation(int(line_number), message.rstrip())
-                    violations_dict[src].append(violation)
+                if match is None:
+                    continue
+                src, violation = self._get_violation(match)
+                src = to_unix_path(os.path.relpath(src))
+                violations_dict[src].append(violation)
         return violations_dict
 
+    def _get_violation(self, match):
+        src, line_number, message = match.groups()
+        # Transform src to a relative path, if it isn't already
+        src = os.path.relpath(src)
+        return src, Violation(int(line_number), message)
+
     def installed(self):
         """
         Method checks if the provided tool is installed.

diff_cover/violationsreporters/violations_reporter.py

@@ -236,7 +236,10 @@
                                 # This is an unreported line.
                                 # We add it with the previous line hit score
                                 line_nodes.append(
-                                    {_hits: last_hit_number, _number: line_number}
+                                    {
+                                        _hits: last_hit_number,
+                                        _number: line_number,
+                                    }
                                 )
 
                 # First case, need to define violations initially
@@ -571,6 +574,29 @@
     exit_codes=[0, 1],
 )
 
+
+class RuffFormatDriver(RegexBasedDriver):
+    def _get_violation(self, match):
+        src = match.groups()[0]
+        # Transform src to a relative path, if it isn't already
+        src = os.path.relpath(src)
+        return src, Violation(Violation.ALL_LINES, "Needs reformat")
+
+
+ruff_format_driver = RuffFormatDriver(
+    name="ruff.format",
+    supported_extensions=["py"],
+    command=["ruff", "format", "--check"],
+    # Match lines of the form:
+    # Would reformat: path/to/file.py
+    # Would reformat: path/to/file2.py
+    expression=r"^Would reformat: ([^:]+)$",
+    command_to_check_install=["ruff", "--version"],
+    # ruff exit code is 1 if there are violations
+    # https://docs.astral.sh/ruff/linter/#exit-codes
+    exit_codes=[0, 1],
+)
+
 """
     Report Flake8 violations.
 """

tests/test_util.py

@@ -78,3 +78,21 @@ def test_open_file_encoding_binary(tmp_path):
     with util.open_file(tmp_path / "some_file.txt", "br", encoding="utf-16") as f:
         assert not hasattr(f, "encoding")
         assert f.read() == b"cafe naive resume"
+
+
+@pytest.mark.parametrize(
+    (
+        "nums",
+        "expected",
+    ),
+    (
+        ([], []),
+        ([1, 2, 3], ["1-3"]),
+        ([1, 2, 1, 2, 2, 3, 3], ["1-3"]),
+        ([1, 2, 3, 5, 6, 7], ["1-3", "5-7"]),
+        ([1, 3, 6, 8], ["1", "3", "6", "8"]),
+        (range(1, 101), ["1-100"]),
+    ),
+)
+def test_merge_ranges(nums, expected):
+    assert util.merge_ranges(nums) == expected