Rename style_guide.Error to style_guide.Violation

Move all Violation related methods from the StyleGuide to our Violation
class.

9 files changed, 185 insertions, 136 deletions

diff --git a/src/flake8/formatting/base.py b/src/flake8/formatting/base.py
index abad254..c4c67d5 100644
--- a/src/flake8/formatting/base.py
+++ b/src/flake8/formatting/base.py
@@ -78,9 +78,10 @@ class BaseFormatter(object):
         method.
 
         :param error:
-            This will be an instance of :class:`~flake8.style_guide.Error`.
+            This will be an instance of
+            :class:`~flake8.style_guide.Violation`.
         :type error:
-            flake8.style_guide.Error
+            flake8.style_guide.Violation
         """
         line = self.format(error)
         source = self.show_source(error)
@@ -92,9 +93,10 @@ class BaseFormatter(object):
         This method **must** be implemented by subclasses.
 
         :param error:
-            This will be an instance of :class:`~flake8.style_guide.Error`.
+            This will be an instance of
+            :class:`~flake8.style_guide.Violation`.
         :type error:
-            flake8.style_guide.Error
+            flake8.style_guide.Violation
         :returns:
             The formatted error string.
         :rtype:
@@ -144,9 +146,10 @@ class BaseFormatter(object):
         is reported as generating the problem.
 
         :param error:
-            This will be an instance of :class:`~flake8.style_guide.Error`.
+            This will be an instance of
+            :class:`~flake8.style_guide.Violation`.
         :type error:
-            flake8.style_guide.Error
+            flake8.style_guide.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
diff --git a/src/flake8/statistics.py b/src/flake8/statistics.py
index d555df2..d39750a 100644
--- a/src/flake8/statistics.py
+++ b/src/flake8/statistics.py
@@ -23,9 +23,10 @@ class Statistics(object):
         """Add the fact that the error was seen in the file.
 
         :param error:
-            The Error instance containing the information about the violation.
+            The Violation instance containing the information about the
+            violation.
         :type error:
-            flake8.style_guide.Error
+            flake8.style_guide.Violation
         """
         key = Key.create_from(error)
         if key not in self._store:
@@ -73,7 +74,7 @@ class Key(collections.namedtuple('Key', ['filename', 'code'])):
 
     @classmethod
     def create_from(cls, error):
-        """Create a Key from :class:`flake8.style_guide.Error`."""
+        """Create a Key from :class:`flake8.style_guide.Violation`."""
         return cls(
             filename=error.filename,
             code=error.code,
@@ -115,7 +116,7 @@ class Statistic(object):
 
     @classmethod
     def create_from(cls, error):
-        """Create a Statistic from a :class:`flake8.style_guide.Error`."""
+        """Create a Statistic from a :class:`flake8.style_guide.Violation`."""
         return cls(
             error_code=error.code,
             filename=error.filename,
diff --git a/src/flake8/style_guide.py b/src/flake8/style_guide.py
index 07d9e06..124c7d5 100644
--- a/src/flake8/style_guide.py
+++ b/src/flake8/style_guide.py
@@ -2,6 +2,7 @@
 import collections
 import contextlib
 import enum
+import functools
 import linecache
 import logging
 
@@ -16,6 +17,17 @@ __all__ = (
 LOG = logging.getLogger(__name__)
 
 
+try:
+    lru_cache = functools.lru_cache
+except AttributeError:
+    def lru_cache(maxsize=128, typed=False):
+        """Stub for missing lru_cache."""
+        def fake_decorator(func):
+            return func
+
+        return fake_decorator
+
+
 # TODO(sigmavirus24): Determine if we need to use enum/enum34
 class Selected(enum.Enum):
     """Enum representing an explicitly or implicitly selected code."""
@@ -38,8 +50,13 @@ class Decision(enum.Enum):
     Selected = 'selected error'
 
 
-Error = collections.namedtuple(
-    'Error',
+@lru_cache(maxsize=512)
+def find_noqa(physical_line):
+    return defaults.NOQA_INLINE_REGEXP.search(physical_line)
+
+
+_Violation = collections.namedtuple(
+    'Violation',
     [
         'code',
         'filename',
@@ -51,6 +68,84 @@ Error = collections.namedtuple(
 )
 
 
+class Violation(_Violation):
+    """Class representing a violation reported by Flake8."""
+
+    def is_inline_ignored(self, disable_noqa):
+        # type: (Violation) -> bool
+        """Determine if an 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):
+        """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(object):
     """A class for managing the decision process around violations.
 
@@ -127,7 +222,7 @@ class DecisionEngine(object):
         return Selected.Implicitly
 
     def more_specific_decision_for(self, code):
-        # type: (Error) -> Decision
+        # type: (Violation) -> Decision
         select = find_first_match(code, self.all_selected)
         extra_select = find_first_match(code, self.extended_selected)
         ignore = find_first_match(code, self.ignored)
@@ -221,73 +316,6 @@ class StyleGuide(object):
         """
         return self.decider.decision_for(code)
 
-    def is_inline_ignored(self, error):
-        # type: (Error) -> bool
-        """Determine if an comment has been added to ignore this line."""
-        physical_line = error.physical_line
-        # TODO(sigmavirus24): Determine how to handle stdin with linecache
-        if self.options.disable_noqa:
-            return False
-
-        if physical_line is None:
-            physical_line = linecache.getline(error.filename,
-                                              error.line_number)
-        noqa_match = defaults.NOQA_INLINE_REGEXP.search(physical_line)
-        if noqa_match is None:
-            LOG.debug('%r is not inline ignored', error)
-            return False
-
-        codes_str = noqa_match.groupdict()['codes']
-        if codes_str is None:
-            LOG.debug('%r is ignored by a blanket ``# noqa``', error)
-            return True
-
-        codes = set(utils.parse_comma_separated_list(codes_str))
-        if error.code in codes or error.code.startswith(tuple(codes)):
-            LOG.debug('%r is ignored specifically inline with ``# noqa: %s``',
-                      error, codes_str)
-            return True
-
-        LOG.debug('%r is not ignored inline with ``# noqa: %s``',
-                  error, codes_str)
-        return False
-
-    def is_in_diff(self, error):
-        # type: (Error) -> bool
-        """Determine if an error 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 self._parsed_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 = self._parsed_diff.get(error.filename)
-        if not line_numbers:
-            return False
-
-        return error.line_number in line_numbers
-
     def handle_error(self, code, filename, line_number, column_number, text,
                      physical_line=None):
         # type: (str, str, int, int, str) -> int
@@ -313,17 +341,18 @@ class StyleGuide(object):
         :rtype:
             int
         """
+        disable_noqa = self.options.disable_noqa
         # NOTE(sigmavirus24): Apparently we're provided with 0-indexed column
         # numbers so we have to offset that here. Also, if a SyntaxError is
         # caught, column_number may be None.
         if not column_number:
             column_number = 0
-        error = Error(code, filename, line_number, column_number + 1, text,
-                      physical_line)
+        error = Violation(code, filename, line_number, column_number + 1,
+                          text, physical_line)
         error_is_selected = (self.should_report_error(error.code) is
                              Decision.Selected)
-        is_not_inline_ignored = self.is_inline_ignored(error) is False
-        is_included_in_diff = self.is_in_diff(error)
+        is_not_inline_ignored = error.is_inline_ignored(disable_noqa) is False
+        is_included_in_diff = error.is_in(self._parsed_diff)
         if (error_is_selected and is_not_inline_ignored and
                 is_included_in_diff):
             self.formatter.handle(error)
diff --git a/tests/unit/test_base_formatter.py b/tests/unit/test_base_formatter.py
index bb54358..87b5fee 100644
--- a/tests/unit/test_base_formatter.py
+++ b/tests/unit/test_base_formatter.py
@@ -51,7 +51,7 @@ def test_show_source_returns_nothing_when_not_showing_source():
     """Ensure we return nothing when users want nothing."""
     formatter = base.BaseFormatter(options(show_source=False))
     assert formatter.show_source(
-        style_guide.Error('A000', 'file.py', 1, 1, 'error text', 'line')
+        style_guide.Violation('A000', 'file.py', 1, 1, 'error text', 'line')
     ) is ''
 
 
@@ -59,7 +59,7 @@ def test_show_source_returns_nothing_when_there_is_source():
     """Ensure we return nothing when there is no line."""
     formatter = base.BaseFormatter(options(show_source=True))
     assert formatter.show_source(
-        style_guide.Error('A000', 'file.py', 1, 1, 'error text', None)
+        style_guide.Violation('A000', 'file.py', 1, 1, 'error text', None)
     ) is ''
 
 
@@ -71,7 +71,7 @@ def test_show_source_returns_nothing_when_there_is_source():
 def test_show_source_updates_physical_line_appropriately(line, column):
     """Ensure the error column is appropriately indicated."""
     formatter = base.BaseFormatter(options(show_source=True))
-    error = style_guide.Error('A000', 'file.py', 1, column, 'error', line)
+    error = style_guide.Violation('A000', 'file.py', 1, column, 'error', line)
     output = formatter.show_source(error)
     _, pointer = output.rsplit('\n', 1)
     assert pointer.count(' ') == (column - 1)
@@ -149,7 +149,7 @@ 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.Error(
+    error = style_guide.Violation(
         code='A001',
         filename='example.py',
         line_number=1,
diff --git a/tests/unit/test_filenameonly_formatter.py b/tests/unit/test_filenameonly_formatter.py
index caa0ae3..b423ee3 100644
--- a/tests/unit/test_filenameonly_formatter.py
+++ b/tests/unit/test_filenameonly_formatter.py
@@ -17,14 +17,15 @@ def test_caches_filenames_already_printed():
     formatter = default.FilenameOnly(options())
     assert formatter.filenames_already_printed == set()
 
-    formatter.format(style_guide.Error('code', 'file.py', 1, 1, 'text', 'l'))
+    formatter.format(
+        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.Error('code', 'file.py', 1, 1, 'text', '1')
+    error = style_guide.Violation('code', 'file.py', 1, 1, 'text', '1')
 
     assert formatter.format(error) == 'file.py'
     assert formatter.format(error) is None
@@ -33,6 +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.Error('code', 'file.py', 1, 1, 'text', '1')
+    error = style_guide.Violation('code', 'file.py', 1, 1, 'text', '1')
 
     assert formatter.show_source(error) is None
diff --git a/tests/unit/test_nothing_formatter.py b/tests/unit/test_nothing_formatter.py
index ce8087f..a1fd683 100644
--- a/tests/unit/test_nothing_formatter.py
+++ b/tests/unit/test_nothing_formatter.py
@@ -15,7 +15,7 @@ def options(**kwargs):
 def test_format_returns_nothing():
     """Verify Nothing.format returns None."""
     formatter = default.Nothing(options())
-    error = style_guide.Error('code', 'file.py', 1, 1, 'text', '1')
+    error = style_guide.Violation('code', 'file.py', 1, 1, 'text', '1')
 
     assert formatter.format(error) is None
 
@@ -23,6 +23,6 @@ def test_format_returns_nothing():
 def test_show_source_returns_nothing():
     """Verify Nothing.show_source returns None."""
     formatter = default.Nothing(options())
-    error = style_guide.Error('code', 'file.py', 1, 1, 'text', '1')
+    error = style_guide.Violation('code', 'file.py', 1, 1, 'text', '1')
 
     assert formatter.show_source(error) is None
diff --git a/tests/unit/test_statistics.py b/tests/unit/test_statistics.py
index f95c638..31d6276 100644
--- a/tests/unit/test_statistics.py
+++ b/tests/unit/test_statistics.py
@@ -11,7 +11,7 @@ DEFAULT_TEXT = 'Default text'
 
 def make_error(**kwargs):
     """Create errors with a bunch of default values."""
-    return style_guide.Error(
+    return style_guide.Violation(
         code=kwargs.pop('code', DEFAULT_ERROR_CODE),
         filename=kwargs.pop('filename', DEFAULT_FILENAME),
         line_number=kwargs.pop('line_number', 1),
diff --git a/tests/unit/test_style_guide.py b/tests/unit/test_style_guide.py
index b3641c6..84c47ff 100644
--- a/tests/unit/test_style_guide.py
+++ b/tests/unit/test_style_guide.py
@@ -19,46 +19,6 @@ def create_options(**kwargs):
     return optparse.Values(kwargs)
 
 
-@pytest.mark.parametrize('error_code,physical_line,expected_result', [
-    ('E111', 'a = 1', False),
-    ('E121', 'a = 1  # noqa: E111', False),
-    ('E121', 'a = 1  # noqa: E111,W123,F821', False),
-    ('E111', 'a = 1  # noqa: E111,W123,F821', True),
-    ('W123', 'a = 1  # noqa: E111,W123,F821', True),
-    ('E111', 'a = 1  # noqa: E11,W123,F821', True),
-    ('E111', 'a = 1  # noqa, analysis:ignore', True),
-    ('E111', 'a = 1  # noqa analysis:ignore', True),
-    ('E111', 'a = 1  # noqa - We do not care', True),
-    ('E111', 'a = 1  # noqa: We do not care', True),
-])
-def test_is_inline_ignored(error_code, physical_line, expected_result):
-    """Verify that we detect inline usage of ``# noqa``."""
-    guide = style_guide.StyleGuide(create_options(select=['E', 'W', 'F']),
-                                   listener_trie=None,
-                                   formatter=None)
-    error = style_guide.Error(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.
-
-    with mock.patch('linecache.getline', return_value=physical_line):
-        assert guide.is_inline_ignored(error) is expected_result
-
-
-def test_disable_is_inline_ignored():
-    """Verify that is_inline_ignored exits immediately if disabling NoQA."""
-    guide = style_guide.StyleGuide(create_options(disable_noqa=True),
-                                   listener_trie=None,
-                                   formatter=None)
-    error = style_guide.Error('E121', 'filename.py', 1, 1, 'error text',
-                              'line')
-
-    with mock.patch('linecache.getline') as getline:
-        assert guide.is_inline_ignored(error) is False
-
-    assert getline.called is False
-
-
 @pytest.mark.parametrize('select_list,ignore_list,error_code', [
     (['E111', 'E121'], [], 'E111'),
     (['E111', 'E121'], [], 'E121'),
@@ -76,8 +36,8 @@ def test_handle_error_notifies_listeners(select_list, ignore_list, error_code):
 
     with mock.patch('linecache.getline', return_value=''):
         guide.handle_error(error_code, 'stdin', 1, 0, 'error found')
-    error = style_guide.Error(error_code, 'stdin', 1, 1, 'error found',
-                              None)
+    error = style_guide.Violation(
+        error_code, 'stdin', 1, 1, 'error found', None)
     listener_trie.notify.assert_called_once_with(error_code, error)
     formatter.handle.assert_called_once_with(error)
 
diff --git a/tests/unit/test_violation.py b/tests/unit/test_violation.py
new file mode 100644
index 0000000..fa75278
--- /dev/null
+++ b/tests/unit/test_violation.py
@@ -0,0 +1,55 @@
+"""Tests for the flake8.style_guide.Violation class."""
+import mock
+import pytest
+
+from flake8 import style_guide
+
+
+@pytest.mark.parametrize('error_code,physical_line,expected_result', [
+    ('E111', 'a = 1', False),
+    ('E121', 'a = 1  # noqa: E111', False),
+    ('E121', 'a = 1  # noqa: E111,W123,F821', False),
+    ('E111', 'a = 1  # noqa: E111,W123,F821', True),
+    ('W123', 'a = 1  # noqa: E111,W123,F821', True),
+    ('E111', 'a = 1  # noqa: E11,W123,F821', True),
+    ('E111', 'a = 1  # noqa, analysis:ignore', True),
+    ('E111', 'a = 1  # noqa analysis:ignore', True),
+    ('E111', 'a = 1  # noqa - We do not care', True),
+    ('E111', 'a = 1  # noqa: We do not care', True),
+])
+def test_is_inline_ignored(error_code, physical_line, expected_result):
+    """Verify that we detect inline usage of ``# noqa``."""
+    error = style_guide.Violation(
+        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.
+
+    with mock.patch('linecache.getline', return_value=physical_line):
+        assert error.is_inline_ignored(False) is expected_result
+
+
+def test_disable_is_inline_ignored():
+    """Verify that is_inline_ignored exits immediately if disabling NoQA."""
+    error = style_guide.Violation(
+        'E121', 'filename.py', 1, 1, 'error text', 'line')
+
+    with mock.patch('linecache.getline') as getline:
+        assert error.is_inline_ignored(True) is False
+
+    assert getline.called is False
+
+
+@pytest.mark.parametrize('violation_file,violation_line,diff,expected', [
+    ('file.py', 10, {}, True),
+    ('file.py', 1, {'file.py': range(1, 2)}, True),
+    ('file.py', 10, {'file.py': range(1, 2)}, False),
+    ('file.py', 1, {'other.py': range(1, 2)}, False),
+    ('file.py', 10, {'other.py': range(1, 2)}, False),
+])
+def test_violation_is_in_diff(violation_file, violation_line, diff, expected):
+    """Verify that we find violations within a diff."""
+    violation = style_guide.Violation(
+        'E001', violation_file, violation_line, 1, 'warning', 'line',
+    )
+
+    assert violation.is_in(diff) is expected