Source code for flake8.checker

"""Checker Manager and Checker classes."""
import collections
import errno
import logging
import signal
import sys
import tokenize
from typing import List, Optional, Tuple

    import multiprocessing
except ImportError:
    multiprocessing = None

from flake8 import defaults
from flake8 import exceptions
from flake8 import processor
from flake8 import utils

LOG = logging.getLogger(__name__)

    # ENOSPC: Added by sigmavirus24
    # > On some operating systems (OSX), multiprocessing may cause an
    # > ENOSPC error while trying to trying to create a Semaphore.
    # > In those cases, we should replace the customized Queue Report
    # > class with pep8's StandardReport class to ensure users don't run
    # > into this problem.
    # > (See also:
    # NOTE(sigmavirus24): When adding to this list, include the reasoning
    # on the lines before the error code and always append your error
    # code. Further, please always add a trailing `,` to reduce the visual
    # noise in diffs.

[docs]class Manager(object): """Manage the parallelism and checker instances for each plugin and file. This class will be responsible for the following: - Determining the parallelism of Flake8, e.g.: * Do we use :mod:`multiprocessing` or is it unavailable? * Do we automatically decide on the number of jobs to use or did the user provide that? - Falling back to a serial way of processing files if we run into an OSError related to :mod:`multiprocessing` - Organizing the results of each checker so we can group the output together and make our output deterministic. """ def __init__(self, style_guide, arguments, checker_plugins): """Initialize our Manager instance. :param style_guide: The instantiated style guide for this instance of Flake8. :type style_guide: flake8.style_guide.StyleGuide :param list arguments: The extra arguments parsed from the CLI (if any) :param checker_plugins: The plugins representing checks parsed from entry-points. :type checker_plugins: flake8.plugins.manager.Checkers """ self.arguments = arguments self.style_guide = style_guide self.options = style_guide.options self.checks = checker_plugins = self._job_count() self.processes = [] self.checkers = [] self.statistics = { "files": 0, "logical lines": 0, "physical lines": 0, "tokens": 0, } def _process_statistics(self): for checker in self.checkers: for statistic in defaults.STATISTIC_NAMES: self.statistics[statistic] += checker.statistics[statistic] self.statistics["files"] += len(self.checkers) def _job_count(self): # type: () -> int # First we walk through all of our error cases: # - multiprocessing library is not present # - we're running on windows in which case we know we have significant # implemenation issues # - the user provided stdin and that's not something we can handle # well # - we're processing a diff, which again does not work well with # multiprocessing and which really shouldn't require multiprocessing # - the user provided some awful input if not multiprocessing: LOG.warning( "The multiprocessing module is not available. " "Ignoring --jobs arguments." ) return 0 if ( utils.is_windows() and not utils.can_run_multiprocessing_on_windows() ): LOG.warning( "The --jobs option is not available on Windows due to" " a bug ( in " "Python 2.7.11+ and 3.3+. We have detected that you " "are running an unsupported version of Python on " "Windows. Ignoring --jobs arguments." ) return 0 if utils.is_using_stdin(self.arguments): LOG.warning( "The --jobs option is not compatible with supplying " "input using - . Ignoring --jobs arguments." ) return 0 if self.options.diff: LOG.warning( "The --diff option was specified with --jobs but " "they are not compatible. Ignoring --jobs arguments." ) return 0 jobs = if jobs != "auto" and not jobs.isdigit(): LOG.warning( '"%s" is not a valid parameter to --jobs. Must be one ' 'of "auto" or a numerical value, e.g., 4.', jobs, ) return 0 # If the value is "auto", we want to let the multiprocessing library # decide the number based on the number of CPUs. However, if that # function is not implemented for this particular value of Python we # default to 1 if jobs == "auto": try: return multiprocessing.cpu_count() except NotImplementedError: return 0 # Otherwise, we know jobs should be an integer and we can just convert # it to an integer return int(jobs) def _handle_results(self, filename, results): style_guide = self.style_guide reported_results_count = 0 for (error_code, line_number, column, text, physical_line) in results: reported_results_count += style_guide.handle_error( code=error_code, filename=filename, line_number=line_number, column_number=column, text=text, physical_line=physical_line, ) return reported_results_count
[docs] def is_path_excluded(self, path): # type: (str) -> bool """Check if a path is excluded. :param str path: Path to check against the exclude patterns. :returns: True if there are exclude patterns and the path matches, otherwise False. :rtype: bool """ if path == "-": if self.options.stdin_display_name == "stdin": return False path = self.options.stdin_display_name return utils.matches_filename( path, patterns=self.options.exclude, log_message='"%(path)s" has %(whether)sbeen excluded', logger=LOG, )
[docs] def make_checkers(self, paths=None): # type: (List[str]) -> None """Create checkers for each file.""" if paths is None: paths = self.arguments if not paths: paths = ["."] filename_patterns = self.options.filename running_from_vcs = self.options._running_from_vcs running_from_diff = self.options.diff # NOTE(sigmavirus24): Yes this is a little unsightly, but it's our # best solution right now. def should_create_file_checker(filename, argument): """Determine if we should create a file checker.""" matches_filename_patterns = utils.fnmatch( filename, filename_patterns ) is_stdin = filename == "-" # NOTE(sigmavirus24): If a user explicitly specifies something, # e.g, ``flake8 bin/script`` then we should run Flake8 against # that. Since should_create_file_checker looks to see if the # filename patterns match the filename, we want to skip that in # the event that the argument and the filename are identical. # If it was specified explicitly, the user intended for it to be # checked. explicitly_provided = ( not running_from_vcs and not running_from_diff and (argument == filename) ) return ( explicitly_provided or matches_filename_patterns ) or is_stdin checks = self.checks.to_dictionary() checkers = ( FileChecker(filename, checks, self.options) for argument in paths for filename in utils.filenames_from( argument, self.is_path_excluded ) if should_create_file_checker(filename, argument) ) self.checkers = [ checker for checker in checkers if checker.should_process ]"Checking %d files", len(self.checkers))
[docs] def report(self): # type: () -> Tuple[int, int] """Report all of the errors found in the managed file checkers. This iterates over each of the checkers and reports the errors sorted by line number. :returns: A tuple of the total results found and the results reported. :rtype: tuple(int, int) """ results_reported = results_found = 0 for checker in self.checkers: results = sorted( checker.results, key=lambda tup: (tup[1], tup[2]) ) filename = checker.display_name with self.style_guide.processing_file(filename): results_reported += self._handle_results(filename, results) results_found += len(results) return (results_found, results_reported)
[docs] def run_parallel(self): """Run the checkers in parallel.""" final_results = collections.defaultdict(list) final_statistics = collections.defaultdict(dict) try: pool = multiprocessing.Pool(, _pool_init) except OSError as oserr: if oserr.errno not in SERIAL_RETRY_ERRNOS: raise self.run_serial() return try: pool_map = pool.imap_unordered( _run_checks, self.checkers, chunksize=calculate_pool_chunksize( len(self.checkers), ), ) for ret in pool_map: filename, results, statistics = ret final_results[filename] = results final_statistics[filename] = statistics pool.close() pool.join() pool = None finally: if pool is not None: pool.terminate() pool.join() for checker in self.checkers: filename = checker.display_name checker.results = sorted( final_results[filename], key=lambda tup: (tup[2], tup[2]) ) checker.statistics = final_statistics[filename]
[docs] def run_serial(self): """Run the checkers in serial.""" for checker in self.checkers: checker.run_checks()
[docs] def run(self): """Run all the checkers. This will intelligently decide whether to run the checks in parallel or whether to run them in serial. If running the checks in parallel causes a problem (e.g., this also implements fallback to serial processing. """ try: if > 1 and len(self.checkers) > 1: self.run_parallel() else: self.run_serial() except KeyboardInterrupt: LOG.warning("Flake8 was interrupted by the user") raise exceptions.EarlyQuit("Early quit while running checks")
[docs] def start(self, paths=None): """Start checking files. :param list paths: Path names to check. This is passed directly to :meth:`~Manager.make_checkers`. """"Making checkers") self.make_checkers(paths)
[docs] def stop(self): """Stop checking files.""" self._process_statistics() for proc in self.processes:"Joining %s to the main process", proc.join()
[docs]class FileChecker(object): """Manage running checks for a file and aggregate the results.""" def __init__(self, filename, checks, options): """Initialize our file checker. :param str filename: Name of the file to check. :param checks: The plugins registered to check the file. :type checks: dict :param options: Parsed option values from config and command-line. :type options: optparse.Values """ self.options = options self.filename = filename self.checks = checks self.results = [] self.statistics = { "tokens": 0, "logical lines": 0, "physical lines": 0, } self.processor = self._make_processor() self.display_name = filename self.should_process = False if self.processor is not None: self.display_name = self.processor.filename self.should_process = not self.processor.should_ignore_file() self.statistics["physical lines"] = len(self.processor.lines) def __repr__(self): """Provide helpful debugging representation.""" return "FileChecker for {}".format(self.filename) def _make_processor(self): try: return processor.FileProcessor(self.filename, self.options) except IOError: # If we can not read the file due to an IOError (e.g., the file # does not exist or we do not have the permissions to open it) # then we need to format that exception for the user. # NOTE(sigmavirus24): Historically, pep8 has always reported this # as an E902. We probably *want* a better error code for this # going forward. (exc_type, exception) = sys.exc_info()[:2] message = "{0}: {1}".format(exc_type.__name__, exception)"E902", 0, 0, message) return None
[docs] def report(self, error_code, line_number, column, text, line=None): # type: (str, int, int, str, Optional[str]) -> str """Report an error by storing it in the results list.""" if error_code is None: error_code, text = text.split(" ", 1) physical_line = line # If we're recovering from a problem in _make_processor, we will not # have this attribute. if not physical_line and getattr(self, "processor", None): physical_line = self.processor.line_for(line_number) error = (error_code, line_number, column, text, physical_line) self.results.append(error) return error_code
[docs] def run_check(self, plugin, **arguments): """Run the check in a single plugin.""" LOG.debug("Running %r with %r", plugin, arguments) try: self.processor.keyword_arguments_for( plugin["parameters"], arguments ) except AttributeError as ae: LOG.error("Plugin requested unknown parameters.") raise exceptions.PluginRequestedUnknownParameters( plugin=plugin, exception=ae ) try: return plugin["plugin"](**arguments) except Exception as all_exc: LOG.critical( "Plugin %s raised an unexpected exception", plugin["name"] ) raise exceptions.PluginExecutionFailed( plugin=plugin, exception=all_exc )
@staticmethod def _extract_syntax_information(exception): token = () if len(exception.args) > 1: token = exception.args[1] if len(token) > 2: row, column = token[1:3] else: row, column = (1, 0) if column > 0 and token and isinstance(exception, SyntaxError): # NOTE(sigmavirus24): SyntaxErrors report 1-indexed column # numbers. We need to decrement the column number by 1 at # least. column_offset = 1 row_offset = 0 # See also: physical_line = token[-1] # NOTE(sigmavirus24): Not all "tokens" have a string as the last # argument. In this event, let's skip trying to find the correct # column and row values. if physical_line is not None: # NOTE(sigmavirus24): SyntaxErrors also don't exactly have a # "physical" line so much as what was accumulated by the point # tokenizing failed. # See also: lines = physical_line.rstrip("\n").split("\n") row_offset = len(lines) - 1 logical_line = lines[0] logical_line_length = len(logical_line) if column > logical_line_length: column = logical_line_length row -= row_offset column -= column_offset return row, column
[docs] def run_ast_checks(self): """Run all checks expecting an abstract syntax tree.""" try: ast = self.processor.build_ast() except (ValueError, SyntaxError, TypeError): (exc_type, exception) = sys.exc_info()[:2] row, column = self._extract_syntax_information(exception) "E999", row, column, "%s: %s" % (exc_type.__name__, exception.args[0]), ) return for plugin in self.checks["ast_plugins"]: checker = self.run_check(plugin, tree=ast) # If the plugin uses a class, call the run method of it, otherwise # the call should return something iterable itself try: runner = except AttributeError: runner = checker for (line_number, offset, text, check) in runner: error_code=None, line_number=line_number, column=offset, text=text, )
[docs] def run_logical_checks(self): """Run all checks expecting a logical line.""" comments, logical_line, mapping = self.processor.build_logical_line() if not mapping: return self.processor.update_state(mapping) LOG.debug('Logical line: "%s"', logical_line.rstrip()) for plugin in self.checks["logical_line_plugins"]: self.processor.update_checker_state_for(plugin) results = self.run_check(plugin, logical_line=logical_line) or () for offset, text in results: offset = find_offset(offset, mapping) line_number, column_offset = offset error_code=None, line_number=line_number, column=column_offset, text=text, ) self.processor.next_logical_line()
[docs] def run_physical_checks(self, physical_line, override_error_line=None): """Run all checks for a given physical line. A single physical check may return multiple errors. """ for plugin in self.checks["physical_line_plugins"]: self.processor.update_checker_state_for(plugin) result = self.run_check(plugin, physical_line=physical_line) if result is not None: # This is a single result if first element is an int column_offset = None try: column_offset = result[0] except (IndexError, TypeError): pass if isinstance(column_offset, int): # If we only have a single result, convert to a collection result = (result,) for result_single in result: column_offset, text = result_single error_code = error_code=None, line_number=self.processor.line_number, column=column_offset, text=text, line=(override_error_line or physical_line), ) self.processor.check_physical_error( error_code, physical_line )
[docs] def process_tokens(self): """Process tokens and trigger checks. This can raise a :class:`flake8.exceptions.InvalidSyntax` exception. Instead of using this directly, you should use :meth:`flake8.checker.FileChecker.run_checks`. """ parens = 0 statistics = self.statistics file_processor = self.processor for token in file_processor.generate_tokens(): statistics["tokens"] += 1 self.check_physical_eol(token) token_type, text = token[0:2] processor.log_token(LOG, token) if token_type == tokenize.OP: parens = processor.count_parentheses(parens, text) elif parens == 0: if processor.token_is_newline(token): self.handle_newline(token_type) if file_processor.tokens: # If any tokens are left over, process them self.run_physical_checks(file_processor.lines[-1]) self.run_logical_checks()
[docs] def run_checks(self): """Run checks against the file.""" try: self.process_tokens() except exceptions.InvalidSyntax as exc: exc.error_code, exc.line_number, exc.column_number, exc.error_message, ) self.run_ast_checks() logical_lines = self.processor.statistics["logical lines"] self.statistics["logical lines"] = logical_lines return self.filename, self.results, self.statistics
[docs] def handle_newline(self, token_type): """Handle the logic when encountering a newline token.""" if token_type == tokenize.NEWLINE: self.run_logical_checks() self.processor.reset_blank_before() elif len(self.processor.tokens) == 1: # The physical line contains only this token. self.processor.visited_new_blank_line() self.processor.delete_first_token() else: self.run_logical_checks()
[docs] def check_physical_eol(self, token): """Run physical checks if and only if it is at the end of the line.""" if processor.is_eol_token(token): # Obviously, a newline token ends a single physical line. self.run_physical_checks(token[4]) elif processor.is_multiline_string(token): # Less obviously, a string that contains newlines is a # multiline string, either triple-quoted or with internal # newlines backslash-escaped. Check every physical line in the # string *except* for the last one: its newline is outside of # the multiline string, so we consider it a regular physical # line, and will check it like any other physical line. # # Subtleties: # - have to wind self.line_number back because initially it # points to the last line of the string, and we want # check_physical() to give accurate feedback line_no = token[2][0] with self.processor.inside_multiline(line_number=line_no): for line in self.processor.split_line(token): self.run_physical_checks( line + "\n", override_error_line=token[4] )
def _pool_init(): """Ensure correct signaling of ^C using multiprocessing.Pool.""" signal.signal(signal.SIGINT, signal.SIG_IGN) def calculate_pool_chunksize(num_checkers, num_jobs): """Determine the chunksize for the multiprocessing Pool. - For chunksize, see: # noqa - This formula, while not perfect, aims to give each worker two batches of work. - See: - See: """ return max(num_checkers // (num_jobs * 2), 1) def _run_checks(checker): return checker.run_checks() def find_offset(offset, mapping): """Find the offset tuple for a single offset.""" if isinstance(offset, tuple): return offset for token_offset, position in mapping: if offset <= token_offset: break return (position[0], position[1] + offset - token_offset)