"""Implementation of the StyleGuide used by Flake8.""" import collections import contextlib import enum import linecache import logging from flake8 import defaults from flake8 import statistics from flake8 import utils __all__ = ( 'StyleGuide', ) LOG = logging.getLogger(__name__) # TODO(sigmavirus24): Determine if we need to use enum/enum34 class Selected(enum.Enum): """Enum representing an explicitly or implicitly selected code.""" Explicitly = 'explicitly selected' Implicitly = 'implicitly selected' class Ignored(enum.Enum): """Enum representing an explicitly or implicitly ignored code.""" Explicitly = 'explicitly ignored' Implicitly = 'implicitly ignored' class Decision(enum.Enum): """Enum representing whether a code should be ignored or selected.""" Ignored = 'ignored error' Selected = 'selected error' Error = collections.namedtuple( 'Error', [ 'code', 'filename', 'line_number', 'column_number', 'text', 'physical_line', ], ) class StyleGuide(object): """Manage a Flake8 user's style guide.""" def __init__(self, options, listener_trie, formatter): """Initialize our StyleGuide. .. todo:: Add parameter documentation. """ self.options = options self.listener = listener_trie self.formatter = formatter self.stats = statistics.Statistics() self._selected = tuple(options.select) self._extended_selected = tuple(sorted( options.extended_default_select, reverse=True, )) self._enabled_extensions = tuple(options.enable_extensions) self._all_selected = tuple(sorted( self._selected + self._enabled_extensions, reverse=True, )) self._ignored = tuple(sorted(options.ignore, reverse=True)) self._decision_cache = {} self._parsed_diff = {} def is_user_selected(self, code): # type: (str) -> Union[Selected, Ignored] """Determine if the code has been selected by the user. :param str code: The code for the check that has been run. :returns: Selected.Implicitly if the selected list is empty, Selected.Explicitly if the selected list is not empty and a match was found, Ignored.Implicitly if the selected list is not empty but no match was found. """ if self._all_selected and code.startswith(self._all_selected): return Selected.Explicitly if (not self._all_selected and (self._extended_selected and code.startswith(self._extended_selected))): # If it was not explicitly selected, it may have been implicitly # selected because the check comes from a plugin that is enabled by # default return Selected.Implicitly return Ignored.Implicitly def is_user_ignored(self, code): # type: (str) -> Union[Selected, Ignored] """Determine if the code has been ignored by the user. :param str code: The code for the check that has been run. :returns: Selected.Implicitly if the ignored list is empty, Ignored.Explicitly if the ignored list is not empty and a match was found, Selected.Implicitly if the ignored list is not empty but no match was found. """ if self._ignored and code.startswith(self._ignored): return Ignored.Explicitly return Selected.Implicitly @contextlib.contextmanager def processing_file(self, filename): """Record the fact that we're processing the file's results.""" self.formatter.beginning(filename) yield self self.formatter.finished(filename) def _decision_for(self, code): # type: (Error) -> 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) if select and ignore: return find_more_specific(select, ignore) if extra_select and ignore: return find_more_specific(extra_select, ignore) if select or (extra_select and self._selected == defaults.SELECT): return Decision.Selected if select is None and extra_select is None and ignore is not None: return Decision.Ignored if self._selected != defaults.SELECT and select is None: return Decision.Ignored return Decision.Selected def should_report_error(self, code): # type: (str) -> Decision """Determine if the error code should be reported or ignored. This method only cares about the select and ignore rules as specified by the user in their configuration files and command-line flags. This method does not look at whether the specific line is being ignored in the file itself. :param str code: The code for the check that has been run. """ decision = self._decision_cache.get(code) if decision is None: LOG.debug('Deciding if "%s" should be reported', code) selected = self.is_user_selected(code) ignored = self.is_user_ignored(code) LOG.debug('The user configured "%s" to be "%s", "%s"', code, selected, ignored) if ((selected is Selected.Explicitly or selected is Selected.Implicitly) and ignored is Selected.Implicitly): decision = Decision.Selected elif ((selected is Selected.Explicitly and ignored is Ignored.Explicitly) or (selected is Ignored.Implicitly and ignored is Selected.Implicitly)): decision = self._decision_for(code) elif (selected is Ignored.Implicitly or ignored is Ignored.Explicitly): decision = Decision.Ignored # pylint: disable=R0204 self._decision_cache[code] = decision LOG.debug('"%s" will be "%s"', code, decision) return decision 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 """Handle an error reported by a check. :param str code: The error code found, e.g., E123. :param str filename: The file in which the error was found. :param int line_number: The line number (where counting starts at 1) at which the error occurs. :param int column_number: The column number (where counting starts at 1) at which the error occurs. :param str text: The text of the error message. :param str physical_line: The actual physical line causing the error. :returns: 1 if the error was reported. 0 if it was ignored. This is to allow for counting of the number of errors found that were not ignored. :rtype: int """ # 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_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) if (error_is_selected and is_not_inline_ignored and is_included_in_diff): self.formatter.handle(error) self.stats.record(error) self.listener.notify(error.code, error) return 1 return 0 def add_diff_ranges(self, diffinfo): """Update the StyleGuide to filter out information not in the diff. This provides information to the StyleGuide so that only the errors in the line number ranges are reported. :param dict diffinfo: Dictionary mapping filenames to sets of line number ranges. """ self._parsed_diff = diffinfo def find_more_specific(selected, ignored): if selected.startswith(ignored) and selected != ignored: return Decision.Selected return Decision.Ignored def find_first_match(error_code, code_list): startswith = error_code.startswith for code in code_list: if startswith(code): break else: return None return code