break type checking cycles

src/flake8/formatting/base.py

@@ -6,13 +6,10 @@ from typing import IO
 from typing import List
 from typing import Optional
 from typing import Tuple
-from typing import TYPE_CHECKING
 
 from flake8.formatting import _windows_color
-
-if TYPE_CHECKING:
 from flake8.statistics import Statistics
-    from flake8.style_guide import Violation
+from flake8.violation import Violation
 
 
 class BaseFormatter:
@@ -98,9 +95,9 @@ class BaseFormatter:
 
         :param error:
             This will be an instance of
-            :class:`~flake8.style_guide.Violation`.
+            :class:`~flake8.violation.Violation`.
         :type error:
-            flake8.style_guide.Violation
+            flake8.violation.Violation
         """
         line = self.format(error)
         source = self.show_source(error)
@@ -113,9 +110,9 @@ class BaseFormatter:
 
         :param error:
             This will be an instance of
-            :class:`~flake8.style_guide.Violation`.
+            :class:`~flake8.violation.Violation`.
         :type error:
-            flake8.style_guide.Violation
+            flake8.violation.Violation
         :returns:
             The formatted error string.
         :rtype:
@@ -163,9 +160,9 @@ class BaseFormatter:
 
         :param error:
             This will be an instance of
-            :class:`~flake8.style_guide.Violation`.
+            :class:`~flake8.violation.Violation`.
         :type error:
-            flake8.style_guide.Violation
+            flake8.violation.Violation
         :returns:
             The formatted error string if the user wants to show the source.
             If the user does not want to show the source, this will return

src/flake8/formatting/default.py

@@ -1,12 +1,9 @@
 """Default formatting class for Flake8."""
 from typing import Optional
 from typing import Set
-from typing import TYPE_CHECKING
 
 from flake8.formatting import base
-
+from flake8.violation import Violation
-if TYPE_CHECKING:
-    from flake8.style_guide import Violation
 
 COLORS = {
     "bold": "\033[1m",

src/flake8/statistics.py

@@ -4,10 +4,8 @@ from typing import Generator
 from typing import List
 from typing import NamedTuple
 from typing import Optional
-from typing import TYPE_CHECKING
 
-if TYPE_CHECKING:
+from flake8.violation import Violation
-    from flake8.style_guide import Violation
 
 
 class Statistics:
@@ -34,7 +32,7 @@ class Statistics:
             The Violation instance containing the information about the
             violation.
         :type error:
-            flake8.style_guide.Violation
+            flake8.violation.Violation
         """
         key = Key.create_from(error)
         if key not in self._store:
@@ -86,7 +84,7 @@ class Key(NamedTuple):
 
     @classmethod
     def create_from(cls, error: "Violation") -> "Key":
-        """Create a Key from :class:`flake8.style_guide.Violation`."""
+        """Create a Key from :class:`flake8.violation.Violation`."""
         return cls(filename=error.filename, code=error.code)
 
     def matches(self, prefix: str, filename: Optional[str]) -> bool:
@@ -127,7 +125,7 @@ class Statistic:
 
     @classmethod
     def create_from(cls, error: "Violation") -> "Statistic":
-        """Create a Statistic from a :class:`flake8.style_guide.Violation`."""
+        """Create a Statistic from a :class:`flake8.violation.Violation`."""
         return cls(
             error_code=error.code,
             filename=error.filename,

src/flake8/style_guide.py

@@ -5,13 +5,10 @@ import copy
 import enum
 import functools
 import itertools
-import linecache
 import logging
 from typing import Dict
 from typing import Generator
 from typing import List
-from typing import Match
-from typing import NamedTuple
 from typing import Optional
 from typing import Sequence
 from typing import Set
@@ -22,6 +19,7 @@ from flake8 import defaults
 from flake8 import statistics
 from flake8 import utils
 from flake8.formatting import base as base_formatter
+from flake8.violation import Violation
 
 __all__ = ("StyleGuide",)
 
@@ -49,98 +47,6 @@ class Decision(enum.Enum):
     Selected = "selected error"
 
 
-@functools.lru_cache(maxsize=512)
-def find_noqa(physical_line: str) -> Optional[Match[str]]:
-    return defaults.NOQA_INLINE_REGEXP.search(physical_line)
-
-
-class Violation(NamedTuple):
-    """Class representing a violation reported by Flake8."""
-
-    code: str
-    filename: str
-    line_number: int
-    column_number: int
-    text: str
-    physical_line: Optional[str]
-
-    def is_inline_ignored(self, disable_noqa: bool) -> bool:
-        """Determine if a comment has been added to ignore this line.
-
-        :param bool disable_noqa:
-            Whether or not users have provided ``--disable-noqa``.
-        :returns:
-            True if error is ignored in-line, False otherwise.
-        :rtype:
-            bool
-        """
-        physical_line = self.physical_line
-        # TODO(sigmavirus24): Determine how to handle stdin with linecache
-        if disable_noqa:
-            return False
-
-        if physical_line is None:
-            physical_line = linecache.getline(self.filename, self.line_number)
-        noqa_match = find_noqa(physical_line)
-        if noqa_match is None:
-            LOG.debug("%r is not inline ignored", self)
-            return False
-
-        codes_str = noqa_match.groupdict()["codes"]
-        if codes_str is None:
-            LOG.debug("%r is ignored by a blanket ``# noqa``", self)
-            return True
-
-        codes = set(utils.parse_comma_separated_list(codes_str))
-        if self.code in codes or self.code.startswith(tuple(codes)):
-            LOG.debug(
-                "%r is ignored specifically inline with ``# noqa: %s``",
-                self,
-                codes_str,
-            )
-            return True
-
-        LOG.debug(
-            "%r is not ignored inline with ``# noqa: %s``", self, codes_str
-        )
-        return False
-
-    def is_in(self, diff: Dict[str, Set[int]]) -> bool:
-        """Determine if the violation is included in a diff's line ranges.
-
-        This function relies on the parsed data added via
-        :meth:`~StyleGuide.add_diff_ranges`. If that has not been called and
-        we are not evaluating files in a diff, then this will always return
-        True. If there are diff ranges, then this will return True if the
-        line number in the error falls inside one of the ranges for the file
-        (and assuming the file is part of the diff data). If there are diff
-        ranges, this will return False if the file is not part of the diff
-        data or the line number of the error is not in any of the ranges of
-        the diff.
-
-        :returns:
-            True if there is no diff or if the error is in the diff's line
-            number ranges. False if the error's line number falls outside
-            the diff's line number ranges.
-        :rtype:
-            bool
-        """
-        if not diff:
-            return True
-
-        # NOTE(sigmavirus24): The parsed diff will be a defaultdict with
-        # a set as the default value (if we have received it from
-        # flake8.utils.parse_unified_diff). In that case ranges below
-        # could be an empty set (which is False-y) or if someone else
-        # is using this API, it could be None. If we could guarantee one
-        # or the other, we would check for it more explicitly.
-        line_numbers = diff.get(self.filename)
-        if not line_numbers:
-            return False
-
-        return self.line_number in line_numbers
-
-
 class DecisionEngine:
     """A class for managing the decision process around violations.
 

src/flake8/violation.py

@@ -0,0 +1,107 @@
+"""Contains the Violation error class used internally."""
+import functools
+import linecache
+import logging
+from typing import Dict
+from typing import Match
+from typing import NamedTuple
+from typing import Optional
+from typing import Set
+
+from flake8 import defaults
+from flake8 import utils
+
+
+LOG = logging.getLogger(__name__)
+
+
+@functools.lru_cache(maxsize=512)
+def _find_noqa(physical_line: str) -> Optional[Match[str]]:
+    return defaults.NOQA_INLINE_REGEXP.search(physical_line)
+
+
+class Violation(NamedTuple):
+    """Class representing a violation reported by Flake8."""
+
+    code: str
+    filename: str
+    line_number: int
+    column_number: int
+    text: str
+    physical_line: Optional[str]
+
+    def is_inline_ignored(self, disable_noqa: bool) -> bool:
+        """Determine if a comment has been added to ignore this line.
+
+        :param bool disable_noqa:
+            Whether or not users have provided ``--disable-noqa``.
+        :returns:
+            True if error is ignored in-line, False otherwise.
+        :rtype:
+            bool
+        """
+        physical_line = self.physical_line
+        # TODO(sigmavirus24): Determine how to handle stdin with linecache
+        if disable_noqa:
+            return False
+
+        if physical_line is None:
+            physical_line = linecache.getline(self.filename, self.line_number)
+        noqa_match = _find_noqa(physical_line)
+        if noqa_match is None:
+            LOG.debug("%r is not inline ignored", self)
+            return False
+
+        codes_str = noqa_match.groupdict()["codes"]
+        if codes_str is None:
+            LOG.debug("%r is ignored by a blanket ``# noqa``", self)
+            return True
+
+        codes = set(utils.parse_comma_separated_list(codes_str))
+        if self.code in codes or self.code.startswith(tuple(codes)):
+            LOG.debug(
+                "%r is ignored specifically inline with ``# noqa: %s``",
+                self,
+                codes_str,
+            )
+            return True
+
+        LOG.debug(
+            "%r is not ignored inline with ``# noqa: %s``", self, codes_str
+        )
+        return False
+
+    def is_in(self, diff: Dict[str, Set[int]]) -> bool:
+        """Determine if the violation is included in a diff's line ranges.
+
+        This function relies on the parsed data added via
+        :meth:`~StyleGuide.add_diff_ranges`. If that has not been called and
+        we are not evaluating files in a diff, then this will always return
+        True. If there are diff ranges, then this will return True if the
+        line number in the error falls inside one of the ranges for the file
+        (and assuming the file is part of the diff data). If there are diff
+        ranges, this will return False if the file is not part of the diff
+        data or the line number of the error is not in any of the ranges of
+        the diff.
+
+        :returns:
+            True if there is no diff or if the error is in the diff's line
+            number ranges. False if the error's line number falls outside
+            the diff's line number ranges.
+        :rtype:
+            bool
+        """
+        if not diff:
+            return True
+
+        # NOTE(sigmavirus24): The parsed diff will be a defaultdict with
+        # a set as the default value (if we have received it from
+        # flake8.utils.parse_unified_diff). In that case ranges below
+        # could be an empty set (which is False-y) or if someone else
+        # is using this API, it could be None. If we could guarantee one
+        # or the other, we would check for it more explicitly.
+        line_numbers = diff.get(self.filename)
+        if not line_numbers:
+            return False
+
+        return self.line_number in line_numbers

tests/unit/test_base_formatter.py

@@ -5,9 +5,9 @@ from unittest import mock
 
 import pytest
 
-from flake8 import style_guide
 from flake8.formatting import _windows_color
 from flake8.formatting import base
+from flake8.violation import Violation
 
 
 def options(**kwargs):
@@ -48,7 +48,7 @@ def test_format_needs_to_be_implemented():
     formatter = base.BaseFormatter(options())
     with pytest.raises(NotImplementedError):
         formatter.format(
-            style_guide.Violation("A000", "file.py", 1, 1, "error text", None)
+            Violation("A000", "file.py", 1, 1, "error text", None)
         )
 
 
@@ -57,9 +57,7 @@ def test_show_source_returns_nothing_when_not_showing_source():
     formatter = base.BaseFormatter(options(show_source=False))
     assert (
         formatter.show_source(
-            style_guide.Violation(
+            Violation("A000", "file.py", 1, 1, "error text", "line")
-                "A000", "file.py", 1, 1, "error text", "line"
-            )
         )
         == ""
     )
@@ -70,7 +68,7 @@ def test_show_source_returns_nothing_when_there_is_source():
     formatter = base.BaseFormatter(options(show_source=True))
     assert (
         formatter.show_source(
-            style_guide.Violation("A000", "file.py", 1, 1, "error text", None)
+            Violation("A000", "file.py", 1, 1, "error text", None)
         )
         == ""
     )
@@ -99,7 +97,7 @@ def test_show_source_returns_nothing_when_there_is_source():
 def test_show_source_updates_physical_line_appropriately(line1, line2, column):
     """Ensure the error column is appropriately indicated."""
     formatter = base.BaseFormatter(options(show_source=True))
-    error = style_guide.Violation("A000", "file.py", 1, column, "error", line1)
+    error = Violation("A000", "file.py", 1, column, "error", line1)
     output = formatter.show_source(error)
     assert output == line1 + line2
 
@@ -208,7 +206,7 @@ def test_handle_formats_the_error():
     """Verify that a formatter will call format from handle."""
     formatter = FormatFormatter(options(show_source=False))
     filemock = formatter.output_fd = mock.Mock()
-    error = style_guide.Violation(
+    error = Violation(
         code="A001",
         filename="example.py",
         line_number=1,

tests/unit/test_filenameonly_formatter.py

@@ -1,8 +1,8 @@
 """Tests for the FilenameOnly formatter object."""
 import argparse
 
-from flake8 import style_guide
 from flake8.formatting import default
+from flake8.violation import Violation
 
 
 def options(**kwargs):
@@ -18,16 +18,14 @@ def test_caches_filenames_already_printed():
     formatter = default.FilenameOnly(options())
     assert formatter.filenames_already_printed == set()
 
-    formatter.format(
+    formatter.format(Violation("code", "file.py", 1, 1, "text", "l"))
-        style_guide.Violation("code", "file.py", 1, 1, "text", "l")
-    )
     assert formatter.filenames_already_printed == {"file.py"}
 
 
 def test_only_returns_a_string_once_from_format():
     """Verify format ignores the second error with the same filename."""
     formatter = default.FilenameOnly(options())
-    error = style_guide.Violation("code", "file.py", 1, 1, "text", "1")
+    error = Violation("code", "file.py", 1, 1, "text", "1")
 
     assert formatter.format(error) == "file.py"
     assert formatter.format(error) is None
@@ -36,6 +34,6 @@ def test_only_returns_a_string_once_from_format():
 def test_show_source_returns_nothing():
     """Verify show_source returns nothing."""
     formatter = default.FilenameOnly(options())
-    error = style_guide.Violation("code", "file.py", 1, 1, "text", "1")
+    error = Violation("code", "file.py", 1, 1, "text", "1")
 
     assert formatter.show_source(error) is None

tests/unit/test_nothing_formatter.py

@@ -1,8 +1,8 @@
 """Tests for the Nothing formatter obbject."""
 import argparse
 
-from flake8 import style_guide
 from flake8.formatting import default
+from flake8.violation import Violation
 
 
 def options(**kwargs):
@@ -16,7 +16,7 @@ def options(**kwargs):
 def test_format_returns_nothing():
     """Verify Nothing.format returns None."""
     formatter = default.Nothing(options())
-    error = style_guide.Violation("code", "file.py", 1, 1, "text", "1")
+    error = Violation("code", "file.py", 1, 1, "text", "1")
 
     assert formatter.format(error) is None
 
@@ -24,6 +24,6 @@ def test_format_returns_nothing():
 def test_show_source_returns_nothing():
     """Verify Nothing.show_source returns None."""
     formatter = default.Nothing(options())
-    error = style_guide.Violation("code", "file.py", 1, 1, "text", "1")
+    error = Violation("code", "file.py", 1, 1, "text", "1")
 
     assert formatter.show_source(error) is None

tests/unit/test_statistics.py

@@ -2,7 +2,7 @@
 import pytest
 
 from flake8 import statistics as stats
-from flake8 import style_guide
+from flake8.violation import Violation
 
 DEFAULT_ERROR_CODE = "E100"
 DEFAULT_FILENAME = "file.py"
@@ -16,7 +16,7 @@ def make_error(**kwargs):
     kwargs.setdefault("line_number", 1)
     kwargs.setdefault("column_number", 1)
     kwargs.setdefault("text", DEFAULT_TEXT)
-    return style_guide.Violation(**kwargs, physical_line=None)
+    return Violation(**kwargs, physical_line=None)
 
 
 def test_key_creation():

tests/unit/test_violation.py

@@ -1,9 +1,9 @@
-"""Tests for the flake8.style_guide.Violation class."""
+"""Tests for the flake8.violation.Violation class."""
 from unittest import mock
 
 import pytest
 
-from flake8 import style_guide
+from flake8.violation import Violation
 
 
 @pytest.mark.parametrize(
@@ -33,9 +33,7 @@ from flake8 import style_guide
 )
 def test_is_inline_ignored(error_code, physical_line, expected_result):
     """Verify that we detect inline usage of ``# noqa``."""
-    error = style_guide.Violation(
+    error = Violation(error_code, "filename.py", 1, 1, "error text", None)
-        error_code, "filename.py", 1, 1, "error text", None
-    )
     # We want `None` to be passed as the physical line so we actually use our
     # monkey-patched linecache.getline value.
 
@@ -45,9 +43,7 @@ def test_is_inline_ignored(error_code, physical_line, expected_result):
 
 def test_disable_is_inline_ignored():
     """Verify that is_inline_ignored exits immediately if disabling NoQA."""
-    error = style_guide.Violation(
+    error = Violation("E121", "filename.py", 1, 1, "error text", "line")
-        "E121", "filename.py", 1, 1, "error text", "line"
-    )
 
     with mock.patch("linecache.getline") as getline:
         assert error.is_inline_ignored(True) is False
@@ -67,13 +63,8 @@ def test_disable_is_inline_ignored():
 )
 def test_violation_is_in_diff(violation_file, violation_line, diff, expected):
     """Verify that we find violations within a diff."""
-    violation = style_guide.Violation(
+    violation = Violation(
-        "E001",
+        "E001", violation_file, violation_line, 1, "warning", "line"
-        violation_file,
-        violation_line,
-        1,
-        "warning",
-        "line",
     )
 
     assert violation.is_in(diff) is expected