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https://github.com/PyCQA/flake8.git
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Upgrade McCabe checker as an extension; now it uses the AST
This commit is contained in:
Florent Xicluna
parent
740e8b9ad6
commit
1c6ed0526a
2 changed files with 105 additions and 93 deletions
197
flake8/mccabe.py
197
flake8/mccabe.py
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@ -3,35 +3,26 @@
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http://nedbatchelder.com/blog/200803/python_code_complexity_microtool.html
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MIT License.
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"""
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try:
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from compiler import parse # NOQA
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iter_child_nodes = None # NOQA
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except ImportError:
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from ast import parse, iter_child_nodes # NOQA
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from __future__ import with_statement
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import optparse
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import sys
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from flake8.util import skip_warning
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from collections import defaultdict
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WARNING_CODE = "W901"
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from flake8.util import ast, iter_child_nodes
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version = 0.1
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class ASTVisitor:
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VERBOSE = 0
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class ASTVisitor(object):
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"""Performs a depth-first walk of the AST."""
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def __init__(self):
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self.node = None
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self._cache = {}
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def default(self, node, *args):
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if hasattr(node, 'getChildNodes'):
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children = node.getChildNodes()
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else:
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children = iter_child_nodes(node)
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for child in children:
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for child in iter_child_nodes(node):
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self.dispatch(child, *args)
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def dispatch(self, node, *args):
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@ -42,7 +33,6 @@ class ASTVisitor:
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className = klass.__name__
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meth = getattr(self.visitor, 'visit' + className, self.default)
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self._cache[klass] = meth
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return meth(node, *args)
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def preorder(self, tree, visitor, *args):
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@ -52,7 +42,7 @@ class ASTVisitor:
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self.dispatch(tree, *args) # XXX *args make sense?
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class PathNode:
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class PathNode(object):
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def __init__(self, name, look="circle"):
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self.name = name
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self.look = look
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@ -65,7 +55,7 @@ class PathNode:
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return id(self)
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class PathGraph:
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class PathGraph(object):
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def __init__(self, name, entity, lineno):
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self.name = name
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self.entity = entity
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@ -99,7 +89,7 @@ class PathGraphingAstVisitor(ASTVisitor):
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"""
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def __init__(self):
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ASTVisitor.__init__(self)
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super(PathGraphingAstVisitor, self).__init__()
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self.classname = ""
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self.graphs = {}
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self.reset()
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@ -108,7 +98,11 @@ class PathGraphingAstVisitor(ASTVisitor):
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self.graph = None
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self.tail = None
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def visitFunction(self, node):
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def dispatch_list(self, node_list):
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for node in node_list:
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self.dispatch(node)
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def visitFunctionDef(self, node):
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if self.classname:
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entity = '%s%s' % (self.classname, node.name)
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@ -121,7 +115,7 @@ class PathGraphingAstVisitor(ASTVisitor):
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# closure
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pathnode = self.appendPathNode(name)
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self.tail = pathnode
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self.default(node)
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self.dispatch_list(node.body)
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bottom = PathNode("", look='point')
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self.graph.connect(self.tail, bottom)
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self.graph.connect(pathnode, bottom)
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@ -130,16 +124,14 @@ class PathGraphingAstVisitor(ASTVisitor):
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self.graph = PathGraph(name, entity, node.lineno)
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pathnode = PathNode(name)
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self.tail = pathnode
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self.default(node)
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self.dispatch_list(node.body)
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self.graphs["%s%s" % (self.classname, node.name)] = self.graph
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self.reset()
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visitFunctionDef = visitFunction
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def visitClass(self, node):
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def visitClassDef(self, node):
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old_classname = self.classname
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self.classname += node.name + "."
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self.default(node)
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self.dispatch_list(node.body)
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self.classname = old_classname
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def appendPathNode(self, name):
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@ -158,9 +150,9 @@ class PathGraphingAstVisitor(ASTVisitor):
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name = "Stmt %d" % lineno
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self.appendPathNode(name)
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visitAssert = visitAssign = visitAssTuple = visitPrint = \
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visitPrintnl = visitRaise = visitSubscript = visitDecorators = \
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visitPass = visitDiscard = visitGlobal = visitReturn = \
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visitAssert = visitAssign = visitAugAssign = visitDelete = visitPrint = \
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visitRaise = visitYield = visitImport = visitCall = visitSubscript = \
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visitPass = visitContinue = visitBreak = visitGlobal = visitReturn = \
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visitSimpleStatement
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def visitLoop(self, node):
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@ -171,101 +163,119 @@ class PathGraphingAstVisitor(ASTVisitor):
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self.graph = PathGraph(name, name, node.lineno)
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pathnode = PathNode(name)
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self.tail = pathnode
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self.default(node)
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self.dispatch_list(node.body)
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self.graphs["%s%s" % (self.classname, name)] = self.graph
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self.reset()
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else:
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pathnode = self.appendPathNode(name)
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self.tail = pathnode
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self.default(node.body)
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self.dispatch_list(node.body)
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bottom = PathNode("", look='point')
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self.graph.connect(self.tail, bottom)
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self.graph.connect(pathnode, bottom)
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self.tail = bottom
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# TODO: else clause in node.else_
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# TODO: else clause in node.orelse
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visitFor = visitWhile = visitLoop
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def visitIf(self, node):
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name = "If %d" % node.lineno
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pathnode = self.appendPathNode(name)
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if not pathnode:
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return # TODO: figure out what to do with if's outside def's.
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loose_ends = []
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for t, n in node.tests:
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self.dispatch_list(node.body)
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loose_ends.append(self.tail)
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if node.orelse:
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self.tail = pathnode
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self.default(n)
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loose_ends.append(self.tail)
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if node.else_:
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self.tail = pathnode
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self.default(node.else_)
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self.dispatch_list(node.orelse)
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loose_ends.append(self.tail)
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else:
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loose_ends.append(pathnode)
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bottom = PathNode("", look='point')
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for le in loose_ends:
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self.graph.connect(le, bottom)
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self.tail = bottom
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if pathnode:
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bottom = PathNode("", look='point')
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for le in loose_ends:
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self.graph.connect(le, bottom)
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self.tail = bottom
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# TODO: visitTryExcept
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# TODO: visitTryFinally
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# TODO: visitWith
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def visitTryExcept(self, node):
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name = "TryExcept %d" % node.lineno
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pathnode = self.appendPathNode(name)
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loose_ends = []
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self.dispatch_list(node.body)
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loose_ends.append(self.tail)
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for handler in node.handlers:
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self.tail = pathnode
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self.dispatch_list(handler.body)
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loose_ends.append(self.tail)
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if pathnode:
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bottom = PathNode("", look='point')
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for le in loose_ends:
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self.graph.connect(le, bottom)
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self.tail = bottom
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# XXX todo: determine which ones can add to the complexity
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# py2
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# TODO: visitStmt
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# TODO: visitAssName
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# TODO: visitCallFunc
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# TODO: visitConst
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# py3
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# TODO: visitStore
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# TODO: visitCall
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# TODO: visitLoad
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# TODO: visitNum
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# TODO: visitarguments
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# TODO: visitExpr
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def visitWith(self, node):
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name = "With %d" % node.lineno
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self.appendPathNode(name)
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self.dispatch_list(node.body)
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def get_code_complexity(code, min=7, filename='stdin'):
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complex = []
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class McCabeChecker(object):
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"""McCabe cyclomatic complexity checker."""
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name = 'mccabe'
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version = version
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_code = 'C901'
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_error_tmpl = "C901 %r is too complex (%d)"
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max_complexity = 0
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def __init__(self, tree, filename):
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self.tree = tree
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@classmethod
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def add_options(cls, parser):
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parser.add_option('--max-complexity', default=-1, action='store',
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type='int', help="McCabe complexity threshold")
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parser.config_options.append('max-complexity')
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@classmethod
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def parse_options(cls, options):
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cls.max_complexity = options.max_complexity
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def run(self):
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if self.max_complexity < 0:
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return
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visitor = PathGraphingAstVisitor()
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visitor.preorder(self.tree, visitor)
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for graph in visitor.graphs.values():
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graph_complexity = graph.complexity()
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if graph_complexity >= self.max_complexity:
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text = self._error_tmpl % (graph.entity, graph_complexity)
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yield graph.lineno, 0, text, type(self)
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def get_code_complexity(code, min_complexity=7, filename='stdin'):
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try:
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ast = parse(code)
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except (AttributeError, SyntaxError):
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tree = compile(code, filename, "exec", ast.PyCF_ONLY_AST)
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except SyntaxError:
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e = sys.exc_info()[1]
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sys.stderr.write("Unable to parse %s: %s\n" % (filename, e))
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return 0
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visitor = PathGraphingAstVisitor()
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visitor.preorder(ast, visitor)
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for graph in visitor.graphs.values():
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if graph is None:
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# ?
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continue
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if graph.complexity() >= min:
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graph.filename = filename
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if not skip_warning(graph):
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msg = '%s:%d:1: %s %r is too complex (%d)' % (
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filename,
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graph.lineno,
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WARNING_CODE,
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graph.entity,
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graph.complexity(),
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)
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complex.append(msg)
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complx = []
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McCabeChecker.max_complexity = min_complexity
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for lineno, offset, text, check in McCabeChecker(tree, filename):
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complx.append('%s:%d:1: %s' % (filename, lineno, text))
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if len(complex) == 0:
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if len(complx) == 0:
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return 0
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print('\n'.join(complex))
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return len(complex)
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print('\n'.join(complx))
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return len(complx)
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def get_module_complexity(module_path, min=7):
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def get_module_complexity(module_path, min_complexity=7):
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"""Returns the complexity of a module"""
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code = open(module_path, "rU").read() + '\n\n'
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return get_code_complexity(code, min, filename=module_path)
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with open(module_path, "rU") as mod:
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code = mod.read()
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return get_code_complexity(code, min_complexity, filename=module_path)
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def main(argv):
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@ -278,10 +288,11 @@ def main(argv):
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options, args = opar.parse_args(argv)
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text = open(args[0], "rU").read() + '\n\n'
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ast = parse(text)
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with open(args[0], "rU") as mod:
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code = mod.read()
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tree = compile(code, args[0], "exec", ast.PyCF_ONLY_AST)
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visitor = PathGraphingAstVisitor()
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visitor.preorder(ast, visitor)
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visitor.preorder(tree, visitor)
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if options.dot:
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print('graph {')
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1
setup.py
1
setup.py
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@ -36,6 +36,7 @@ setup(
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'console_scripts': ['flake8 = flake8.main:main'],
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'flake8.extension': [
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'F = flake8._pyflakes:FlakesChecker',
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'C90 = flake8.mccabe:McCabeChecker',
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],
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},
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tests_require=['nose'],
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