/pymode/libs/pylint/checkers/design_analysis.py
Python | 331 lines | 247 code | 23 blank | 61 comment | 29 complexity | f07a40edae0d201cd9ccf7c2154733aa MD5 | raw file
- # Copyright (c) 2003-2013 LOGILAB S.A. (Paris, FRANCE).
- # http://www.logilab.fr/ -- mailto:contact@logilab.fr
- #
- # This program is free software; you can redistribute it and/or modify it under
- # the terms of the GNU General Public License as published by the Free Software
- # Foundation; either version 2 of the License, or (at your option) any later
- # version.
- #
- # This program is distributed in the hope that it will be useful, but WITHOUT
- # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
- #
- # You should have received a copy of the GNU General Public License along with
- # this program; if not, write to the Free Software Foundation, Inc.,
- # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- """check for signs of poor design"""
- import re
- from collections import defaultdict
- from astroid import If, InferenceError
- from pylint.interfaces import IAstroidChecker
- from pylint.checkers import BaseChecker
- from pylint.checkers.utils import check_messages
- # regexp for ignored argument name
- IGNORED_ARGUMENT_NAMES = re.compile('_.*')
- MSGS = {
- 'R0901': ('Too many ancestors (%s/%s)',
- 'too-many-ancestors',
- 'Used when class has too many parent classes, try to reduce \
- this to get a simpler (and so easier to use) class.'),
- 'R0902': ('Too many instance attributes (%s/%s)',
- 'too-many-instance-attributes',
- 'Used when class has too many instance attributes, try to reduce \
- this to get a simpler (and so easier to use) class.'),
- 'R0903': ('Too few public methods (%s/%s)',
- 'too-few-public-methods',
- 'Used when class has too few public methods, so be sure it\'s \
- really worth it.'),
- 'R0904': ('Too many public methods (%s/%s)',
- 'too-many-public-methods',
- 'Used when class has too many public methods, try to reduce \
- this to get a simpler (and so easier to use) class.'),
- 'R0911': ('Too many return statements (%s/%s)',
- 'too-many-return-statements',
- 'Used when a function or method has too many return statement, \
- making it hard to follow.'),
- 'R0912': ('Too many branches (%s/%s)',
- 'too-many-branches',
- 'Used when a function or method has too many branches, \
- making it hard to follow.'),
- 'R0913': ('Too many arguments (%s/%s)',
- 'too-many-arguments',
- 'Used when a function or method takes too many arguments.'),
- 'R0914': ('Too many local variables (%s/%s)',
- 'too-many-locals',
- 'Used when a function or method has too many local variables.'),
- 'R0915': ('Too many statements (%s/%s)',
- 'too-many-statements',
- 'Used when a function or method has too many statements. You \
- should then split it in smaller functions / methods.'),
- 'R0923': ('Interface not implemented',
- 'interface-not-implemented',
- 'Used when an interface class is not implemented anywhere.'),
- }
- class MisdesignChecker(BaseChecker):
- """checks for sign of poor/misdesign:
- * number of methods, attributes, local variables...
- * size, complexity of functions, methods
- """
- __implements__ = (IAstroidChecker,)
- # configuration section name
- name = 'design'
- # messages
- msgs = MSGS
- priority = -2
- # configuration options
- options = (('max-args',
- {'default' : 5, 'type' : 'int', 'metavar' : '<int>',
- 'help': 'Maximum number of arguments for function / method'}
- ),
- ('ignored-argument-names',
- {'default' : IGNORED_ARGUMENT_NAMES,
- 'type' :'regexp', 'metavar' : '<regexp>',
- 'help' : 'Argument names that match this expression will be '
- 'ignored. Default to name with leading underscore'}
- ),
- ('max-locals',
- {'default' : 15, 'type' : 'int', 'metavar' : '<int>',
- 'help': 'Maximum number of locals for function / method body'}
- ),
- ('max-returns',
- {'default' : 6, 'type' : 'int', 'metavar' : '<int>',
- 'help': 'Maximum number of return / yield for function / '
- 'method body'}
- ),
- ('max-branches',
- {'default' : 12, 'type' : 'int', 'metavar' : '<int>',
- 'help': 'Maximum number of branch for function / method body'}
- ),
- ('max-statements',
- {'default' : 50, 'type' : 'int', 'metavar' : '<int>',
- 'help': 'Maximum number of statements in function / method '
- 'body'}
- ),
- ('max-parents',
- {'default' : 7,
- 'type' : 'int',
- 'metavar' : '<num>',
- 'help' : 'Maximum number of parents for a class (see R0901).'}
- ),
- ('max-attributes',
- {'default' : 7,
- 'type' : 'int',
- 'metavar' : '<num>',
- 'help' : 'Maximum number of attributes for a class \
- (see R0902).'}
- ),
- ('min-public-methods',
- {'default' : 2,
- 'type' : 'int',
- 'metavar' : '<num>',
- 'help' : 'Minimum number of public methods for a class \
- (see R0903).'}
- ),
- ('max-public-methods',
- {'default' : 20,
- 'type' : 'int',
- 'metavar' : '<num>',
- 'help' : 'Maximum number of public methods for a class \
- (see R0904).'}
- ),
- )
- def __init__(self, linter=None):
- BaseChecker.__init__(self, linter)
- self.stats = None
- self._returns = None
- self._branches = None
- self._used_ifaces = None
- self._ifaces = None
- self._stmts = 0
- def open(self):
- """initialize visit variables"""
- self.stats = self.linter.add_stats()
- self._returns = []
- self._branches = defaultdict(int)
- self._used_ifaces = {}
- self._ifaces = []
- def close(self):
- """check that interface classes are used"""
- for iface in self._ifaces:
- if not iface in self._used_ifaces:
- self.add_message('interface-not-implemented', node=iface)
- @check_messages('too-many-ancestors', 'too-many-instance-attributes',
- 'too-few-public-methods', 'too-many-public-methods',
- 'interface-not-implemented')
- def visit_class(self, node):
- """check size of inheritance hierarchy and number of instance attributes
- """
- # Is the total inheritance hierarchy is 7 or less?
- nb_parents = len(list(node.ancestors()))
- if nb_parents > self.config.max_parents:
- self.add_message('too-many-ancestors', node=node,
- args=(nb_parents, self.config.max_parents))
- # Does the class contain less than 20 attributes for
- # non-GUI classes (40 for GUI)?
- # FIXME detect gui classes
- if len(node.instance_attrs) > self.config.max_attributes:
- self.add_message('too-many-instance-attributes', node=node,
- args=(len(node.instance_attrs),
- self.config.max_attributes))
- # update interface classes structures
- if node.type == 'interface' and node.name != 'Interface':
- self._ifaces.append(node)
- for parent in node.ancestors(False):
- if parent.name == 'Interface':
- continue
- self._used_ifaces[parent] = 1
- try:
- for iface in node.interfaces():
- self._used_ifaces[iface] = 1
- except InferenceError:
- # XXX log ?
- pass
- @check_messages('too-few-public-methods', 'too-many-public-methods')
- def leave_class(self, node):
- """check number of public methods"""
- my_methods = sum(1 for method in node.mymethods()
- if not method.name.startswith('_'))
- all_methods = sum(1 for method in node.methods()
- if not method.name.startswith('_'))
- # Does the class contain less than n public methods ?
- # This checks only the methods defined in the current class,
- # since the user might not have control over the classes
- # from the ancestors. It avoids some false positives
- # for classes such as unittest.TestCase, which provides
- # a lot of assert methods. It doesn't make sense to warn
- # when the user subclasses TestCase to add his own tests.
- if my_methods > self.config.max_public_methods:
- self.add_message('too-many-public-methods', node=node,
- args=(my_methods,
- self.config.max_public_methods))
- # stop here for exception, metaclass and interface classes
- if node.type != 'class':
- return
- # Does the class contain more than n public methods ?
- # This checks all the methods defined by ancestors and
- # by the current class.
- if all_methods < self.config.min_public_methods:
- self.add_message('too-few-public-methods', node=node,
- args=(all_methods,
- self.config.min_public_methods))
- @check_messages('too-many-return-statements', 'too-many-branches',
- 'too-many-arguments', 'too-many-locals',
- 'too-many-statements')
- def visit_function(self, node):
- """check function name, docstring, arguments, redefinition,
- variable names, max locals
- """
- # init branch and returns counters
- self._returns.append(0)
- # check number of arguments
- args = node.args.args
- if args is not None:
- ignored_args_num = len(
- [arg for arg in args
- if self.config.ignored_argument_names.match(arg.name)])
- argnum = len(args) - ignored_args_num
- if argnum > self.config.max_args:
- self.add_message('too-many-arguments', node=node,
- args=(len(args), self.config.max_args))
- else:
- ignored_args_num = 0
- # check number of local variables
- locnum = len(node.locals) - ignored_args_num
- if locnum > self.config.max_locals:
- self.add_message('too-many-locals', node=node,
- args=(locnum, self.config.max_locals))
- # init statements counter
- self._stmts = 1
- @check_messages('too-many-return-statements', 'too-many-branches',
- 'too-many-arguments', 'too-many-locals',
- 'too-many-statements')
- def leave_function(self, node):
- """most of the work is done here on close:
- checks for max returns, branch, return in __init__
- """
- returns = self._returns.pop()
- if returns > self.config.max_returns:
- self.add_message('too-many-return-statements', node=node,
- args=(returns, self.config.max_returns))
- branches = self._branches[node]
- if branches > self.config.max_branches:
- self.add_message('too-many-branches', node=node,
- args=(branches, self.config.max_branches))
- # check number of statements
- if self._stmts > self.config.max_statements:
- self.add_message('too-many-statements', node=node,
- args=(self._stmts, self.config.max_statements))
- def visit_return(self, _):
- """count number of returns"""
- if not self._returns:
- return # return outside function, reported by the base checker
- self._returns[-1] += 1
- def visit_default(self, node):
- """default visit method -> increments the statements counter if
- necessary
- """
- if node.is_statement:
- self._stmts += 1
- def visit_tryexcept(self, node):
- """increments the branches counter"""
- branches = len(node.handlers)
- if node.orelse:
- branches += 1
- self._inc_branch(node, branches)
- self._stmts += branches
- def visit_tryfinally(self, node):
- """increments the branches counter"""
- self._inc_branch(node, 2)
- self._stmts += 2
- def visit_if(self, node):
- """increments the branches counter"""
- branches = 1
- # don't double count If nodes coming from some 'elif'
- if node.orelse and (len(node.orelse) > 1 or
- not isinstance(node.orelse[0], If)):
- branches += 1
- self._inc_branch(node, branches)
- self._stmts += branches
- def visit_while(self, node):
- """increments the branches counter"""
- branches = 1
- if node.orelse:
- branches += 1
- self._inc_branch(node, branches)
- visit_for = visit_while
- def _inc_branch(self, node, branchesnum=1):
- """increments the branches counter"""
- self._branches[node.scope()] += branchesnum
- def register(linter):
- """required method to auto register this checker """
- linter.register_checker(MisdesignChecker(linter))