Move all package files to a pylint package.

1 files changed, 370 insertions, 0 deletions

diff --git a/pylint/checkers/design_analysis.py b/pylint/checkers/design_analysis.py
new file mode 100644
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+++ b/pylint/checkers/design_analysis.py
@@ -0,0 +1,370 @@
+# 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 Function, 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('_.*')
+
+
+def class_is_abstract(klass):
+    """return true if the given class node should be considered as an abstract
+    class
+    """
+    for attr in klass.values():
+        if isinstance(attr, Function):
+            if attr.is_abstract(pass_is_abstract=False):
+                return True
+    return False
+
+
+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.'),
+
+    'R0921': ('Abstract class not referenced',
+              'abstract-class-not-used',
+              'Used when an abstract class is not used as ancestor anywhere.'),
+    'R0922': ('Abstract class is only referenced %s times',
+              'abstract-class-little-used',
+              'Used when an abstract class is used less than X times as \
+              ancestor.'),
+    '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_abstracts = None
+        self._used_ifaces = None
+        self._abstracts = 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_abstracts = {}
+        self._used_ifaces = {}
+        self._abstracts = []
+        self._ifaces = []
+
+    # Check 'R0921', 'R0922', 'R0923'
+    def close(self):
+        """check that abstract/interface classes are used"""
+        for abstract in self._abstracts:
+            if not abstract in self._used_abstracts:
+                self.add_message('abstract-class-not-used', node=abstract)
+            elif self._used_abstracts[abstract] < 2:
+                self.add_message('abstract-class-little-used', node=abstract,
+                                 args=self._used_abstracts[abstract])
+        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',
+                    'abstract-class-not-used', 'abstract-class-little-used',
+                    '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 abstract / interface classes structures
+        if class_is_abstract(node):
+            self._abstracts.append(node)
+        elif 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
+        for parent in node.ancestors():
+            try:
+                self._used_abstracts[parent] += 1
+            except KeyError:
+                self._used_abstracts[parent] = 1
+
+    @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
+
+    # FIXME: make a nice report...
+
+def register(linter):
+    """required method to auto register this checker """
+    linter.register_checker(MisdesignChecker(linter))