[vendor mccabe] Vendor mccabe to reduce supply chain risks and optimize analysis

Author: Pierre-Sassoulas

pylint/extensions/mccabe.py

@@ -2,16 +2,27 @@
 # For details: https://github.com/pylint-dev/pylint/blob/main/LICENSE
 # Copyright (c) https://github.com/pylint-dev/pylint/blob/main/CONTRIBUTORS.txt
 
-"""Module to add McCabe checker class for pylint."""
+# mypy: ignore-errors
+# pylint: disable=consider-using-f-string,inconsistent-return-statements,consider-using-generator,redefined-builtin
+# pylint: disable=super-with-arguments,too-many-function-args,bad-super-call
+
+"""Module to add McCabe checker class for pylint.
+
+Based on:
+http://nedbatchelder.com/blog/200803/python_code_complexity_microtool.html
+Later integrated in pycqa/mccabe under the MIT License then vendored in pylint
+under the GPL License.
+"""
 
 from __future__ import annotations
 
+import ast
+from ast import iter_child_nodes
+from collections import defaultdict
 from collections.abc import Sequence
 from typing import TYPE_CHECKING, Any, TypeAlias, TypeVar
 
 from astroid import nodes
-from mccabe import PathGraph as Mccabe_PathGraph
-from mccabe import PathGraphingAstVisitor as Mccabe_PathGraphingAstVisitor
 
 from pylint import checkers
 from pylint.checkers.utils import only_required_for_messages
@@ -20,6 +31,213 @@
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
+
+class ASTVisitor:
+    """Performs a depth-first walk of the AST."""
+
+    def __init__(self):
+        self.node = None
+        self._cache = {}
+
+    def default(self, node, *args):
+        for child in iter_child_nodes(node):
+            self.dispatch(child, *args)
+
+    def dispatch(self, node, *args):
+        self.node = node
+        klass = node.__class__
+        meth = self._cache.get(klass)
+        if meth is None:
+            className = klass.__name__
+            meth = getattr(self.visitor, "visit" + className, self.default)
+            self._cache[klass] = meth
+        return meth(node, *args)
+
+    def preorder(self, tree, visitor, *args):
+        """Do preorder walk of tree using visitor."""
+        self.visitor = visitor
+        visitor.visit = self.dispatch
+        self.dispatch(tree, *args)  # XXX *args make sense?
+
+
+class PathNode:
+    def __init__(self, name, look="circle"):
+        self.name = name
+        self.look = look
+
+    def to_dot(self):
+        print('node [shape=%s,label="%s"] %d;' % (self.look, self.name, self.dot_id()))
+
+    def dot_id(self):
+        return id(self)
+
+
+class Mccabe_PathGraph:
+    def __init__(self, name, entity, lineno, column=0):
+        self.name = name
+        self.entity = entity
+        self.lineno = lineno
+        self.column = column
+        self.nodes = defaultdict(list)
+
+    def connect(self, n1, n2):
+        self.nodes[n1].append(n2)
+        # Ensure that the destination node is always counted.
+        self.nodes[n2] = []
+
+    def to_dot(self):
+        print("subgraph {")
+        for node in self.nodes:
+            node.to_dot()
+        for node, nexts in self.nodes.items():
+            for next in nexts:
+                print("%s -- %s;" % (node.dot_id(), next.dot_id()))
+        print("}")
+
+    def complexity(self):
+        """Return the McCabe complexity for the graph.
+
+        V-E+2
+        """
+        num_edges = sum([len(n) for n in self.nodes.values()])
+        num_nodes = len(self.nodes)
+        return num_edges - num_nodes + 2
+
+
+class Mccabe_PathGraphingAstVisitor(ASTVisitor):
+    """A visitor for a parsed Abstract Syntax Tree which finds executable
+    statements.
+    """
+
+    def __init__(self):
+        super(Mccabe_PathGraphingAstVisitor, self).__init__()
+        self.classname = ""
+        self.graphs = {}
+        self.reset()
+
+    def reset(self):
+        self.graph = None
+        self.tail = None
+
+    def dispatch_list(self, node_list):
+        for node in node_list:
+            self.dispatch(node)
+
+    def visitFunctionDef(self, node):
+
+        if self.classname:
+            entity = "%s%s" % (self.classname, node.name)
+        else:
+            entity = node.name
+
+        name = "%d:%d: %r" % (node.lineno, node.col_offset, entity)
+
+        if self.graph is not None:
+            # closure
+            pathnode = self.appendPathNode(name)
+            self.tail = pathnode
+            self.dispatch_list(node.body)
+            bottom = PathNode("", look="point")
+            self.graph.connect(self.tail, bottom)
+            self.graph.connect(pathnode, bottom)
+            self.tail = bottom
+        else:
+            self.graph = PathGraph(name, entity, node.lineno, node.col_offset)
+            pathnode = PathNode(name)
+            self.tail = pathnode
+            self.dispatch_list(node.body)
+            self.graphs["%s%s" % (self.classname, node.name)] = self.graph
+            self.reset()
+
+    visitAsyncFunctionDef = visitFunctionDef
+
+    def visitClassDef(self, node):
+        old_classname = self.classname
+        self.classname += node.name + "."
+        self.dispatch_list(node.body)
+        self.classname = old_classname
+
+    def appendPathNode(self, name):
+        if not self.tail:
+            return
+        pathnode = PathNode(name)
+        self.graph.connect(self.tail, pathnode)
+        self.tail = pathnode
+        return pathnode
+
+    def visitSimpleStatement(self, node):
+        if node.lineno is None:
+            lineno = 0
+        else:
+            lineno = node.lineno
+        name = "Stmt %d" % lineno
+        self.appendPathNode(name)
+
+    def default(self, node, *args):
+        if isinstance(node, ast.stmt):
+            self.visitSimpleStatement(node)
+        else:
+            super(PathGraphingAstVisitor, self).default(node, *args)
+
+    def visitLoop(self, node):
+        name = "Loop %d" % node.lineno
+        self._subgraph(node, name)
+
+    visitAsyncFor = visitFor = visitWhile = visitLoop
+
+    def visitIf(self, node):
+        name = "If %d" % node.lineno
+        self._subgraph(node, name)
+
+    def _subgraph(self, node, name, extra_blocks=()):
+        """Create the subgraphs representing any `if` and `for` statements."""
+        if self.graph is None:
+            # global loop
+            self.graph = PathGraph(name, name, node.lineno, node.col_offset)
+            pathnode = PathNode(name)
+            self._subgraph_parse(node, pathnode, extra_blocks)
+            self.graphs["%s%s" % (self.classname, name)] = self.graph
+            self.reset()
+        else:
+            pathnode = self.appendPathNode(name)
+            self._subgraph_parse(node, pathnode, extra_blocks)
+
+    def _subgraph_parse(self, node, pathnode, extra_blocks):
+        """Parse the body and any `else` block of `if` and `for` statements."""
+        loose_ends = []
+        self.tail = pathnode
+        self.dispatch_list(node.body)
+        loose_ends.append(self.tail)
+        for extra in extra_blocks:
+            self.tail = pathnode
+            self.dispatch_list(extra.body)
+            loose_ends.append(self.tail)
+        if node.orelse:
+            self.tail = pathnode
+            self.dispatch_list(node.orelse)
+            loose_ends.append(self.tail)
+        else:
+            loose_ends.append(pathnode)
+        if pathnode:
+            bottom = PathNode("", look="point")
+            for le in loose_ends:
+                self.graph.connect(le, bottom)
+            self.tail = bottom
+
+    def visitTryExcept(self, node):
+        name = "TryExcept %d" % node.lineno
+        self._subgraph(node, name, extra_blocks=node.handlers)
+
+    visitTry = visitTryExcept
+
+    def visitWith(self, node):
+        name = "With %d" % node.lineno
+        self.appendPathNode(name)
+        self.dispatch_list(node.body)
+
+    visitAsyncWith = visitWith
+
+
 _StatementNodes: TypeAlias = (
     nodes.Assert
     | nodes.Assign

pyproject.toml

@@ -45,7 +45,6 @@ dependencies = [
   "dill>=0.3.6; python_version>='3.11'",
   "dill>=0.3.7; python_version>='3.12'",
   "isort>=4.2.5,!=5.13,<7",
-  "mccabe>=0.6,<0.8",
   "platformdirs>=2.2",
   "tomli>=1.1; python_version<'3.11'",
   "tomlkit>=0.10.1",
@@ -178,6 +177,7 @@ lint.ignore = [
   "RUF012", # mutable default values in class attributes
   "UP038",  # Use `X | Y` in `isinstance` call instead of `(X, Y)`
 ]
+lint.per-file-ignores."pylint/extensions/mccabe.py" = [ "UP008", "UP031" ]
 lint.pydocstyle.convention = "pep257"
 
 [tool.isort]