/usr/lib/python3/dist-packages/importmagic/symbols.py is in python3-importmagic 0.1.7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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import ast
import sys
from contextlib import contextmanager
from itertools import chain
from six import string_types
from importmagic.util import parse_ast
try:
import builtins as __builtin__
except:
import __builtin__
class _InvalidSymbol(Exception):
pass
class Scope(object):
GLOBALS = ['__name__', '__file__', '__loader__', '__package__', '__path__']
PYTHON3_BUILTINS = ['PermissionError']
ALL_BUILTINS = set(dir(__builtin__)) | set(GLOBALS) | set(PYTHON3_BUILTINS)
def __init__(self, parent=None, define_builtins=True, is_class=False):
self._parent = parent
self._definitions = set()
self._references = set()
self._children = []
self._cursors = [self]
self._cursor = self
self._define_builtins = define_builtins
self._is_class = is_class
if define_builtins:
self._define_builtin_symbols()
self._add_symbol = []
self._symbol = []
@contextmanager
def start_symbol(self):
self._add_symbol.append(self._add_symbol[-1] if self._add_symbol else self.reference)
try:
yield self
finally:
self.flush_symbol()
@contextmanager
def start_definition(self):
self._add_symbol.append(self.define)
try:
yield self
finally:
self.flush_symbol()
@contextmanager
def start_reference(self):
self._add_symbol.append(self.reference)
try:
yield self
finally:
self.flush_symbol()
def extend_symbol(self, segment, extend_only=False):
if extend_only and not self._symbol:
return
self._symbol.append(segment)
def end_symbol(self):
if self._symbol:
add = self._add_symbol[-1] if self._add_symbol else self.reference
add('.'.join(self._symbol))
self._symbol = []
def flush_symbol(self):
self.end_symbol()
if self._add_symbol:
self._add_symbol.pop()
@classmethod
def from_source(cls, src, trace=False, define_builtins=True):
scope = Scope(define_builtins=define_builtins)
visitor = UnknownSymbolVisitor(scope, trace=trace)
if isinstance(src, string_types):
src = parse_ast(src)
visitor.visit(src)
scope.flush_symbol()
return scope
def _define_builtin_symbols(self):
self._cursor._definitions.update(Scope.ALL_BUILTINS)
def define(self, name):
if '.' in name:
self.reference(name)
else:
self._cursor._definitions.add(name)
def reference(self, name):
self._cursor._references.add(name)
@contextmanager
def enter(self, is_class=False):
child = Scope(self._cursor, is_class=is_class, define_builtins=self._define_builtins)
self._cursor._children.append(child)
self._cursors.append(child)
self._cursor = child
try:
yield child
finally:
child.end_symbol()
self._cursors.pop()
self._cursor = self._cursors[-1]
def find_unresolved_and_unreferenced_symbols(self):
"""Find any unresolved symbols, and unreferenced symbols from this scope.
:returns: ({unresolved}, {unreferenced})
"""
unresolved = set()
unreferenced = self._definitions.copy()
self._collect_unresolved_and_unreferenced(set(), set(), unresolved, unreferenced,
frozenset(self._definitions), start=True)
return unresolved, unreferenced - Scope.ALL_BUILTINS
def _collect_unresolved_and_unreferenced(self, definitions, definitions_excluding_top,
unresolved, unreferenced, top, start=False):
scope_definitions = definitions | self._definitions
scope_definitions_excluding_top = definitions_excluding_top | (set() if start else self._definitions)
# When we're in a class, don't export definitions to descendant scopes
if not self._is_class:
definitions = scope_definitions
definitions_excluding_top = scope_definitions_excluding_top
for reference in self._references:
symbols = set(_symbol_series(reference))
# Symbol has no definition anywhere in ancestor scopes.
if symbols.isdisjoint(scope_definitions):
unresolved.add(reference)
# Symbol is referenced only in the top level scope.
elif not symbols.isdisjoint(top) and symbols.isdisjoint(scope_definitions_excluding_top):
unreferenced -= symbols
# Recurse
for child in self._children:
child._collect_unresolved_and_unreferenced(
definitions, definitions_excluding_top, unresolved, unreferenced, top,
)
def __repr__(self):
return 'Scope(definitions=%r, references=%r, children=%r)' \
% (self._definitions - Scope.ALL_BUILTINS, self._references, self._children)
def _symbol_series(s):
tokens = s.split('.')
return ['.'.join(tokens[:n + 1]) for n in range(len(tokens))]
class UnknownSymbolVisitor(ast.NodeVisitor):
def __init__(self, scope=None, trace=False):
super(UnknownSymbolVisitor, self).__init__()
self._scope = scope or Scope()
self._trace = trace
def visit(self, node):
if node is None:
return
elif isinstance(node, list):
for subnode in node:
self.visit(subnode)
return
if self._trace:
print(node, vars(node))
method = getattr(self, 'visit_%s' % node.__class__.__name__, None)
if method is not None:
try:
method(node)
except Exception:
# print >> sys.stderr, node, vars(node)
raise
else:
self.generic_visit(node)
self._scope.end_symbol()
def visit_Raise(self, node):
if hasattr(node, 'type'): # Python 2: raise A[, B[, C]]
with self._scope.start_reference():
self.visit(node.type)
with self._scope.start_reference():
self.visit(node.inst)
with self._scope.start_reference():
self.visit(node.tback)
else: # Python 3: raise A[ from B]
with self._scope.start_reference():
self.visit(node.exc)
with self._scope.start_reference():
self.visit(node.cause)
def visit_TryExcept(self, node):
for sub in node.body:
with self._scope.start_reference():
self.visit(sub)
self.visit(node.handlers)
for n in node.orelse:
with self._scope.start_reference():
self.visit(n)
def visit_ExceptHandler(self, node):
with self._scope.start_reference():
self.visit(node.type)
with self._scope.start_definition():
if isinstance(node.name, str):
# Python 3
self._scope.extend_symbol(node.name)
else:
self.visit(node.name)
for n in node.body:
with self._scope.start_reference():
self.visit(n)
def visit_Return(self, node):
with self._scope.start_reference():
self.visit(node.value)
def visit_If(self, node):
with self._scope.start_reference():
self.visit(node.test)
for child in node.body:
with self._scope.start_reference():
self.visit(child)
for child in node.orelse:
with self._scope.start_reference():
self.visit(child)
def visit_While(self, node):
return self.visit_If(node)
def visit_FunctionDef(self, node):
self._scope.define(node.name)
self.visit_Lambda(node)
def visit_Lambda(self, node):
for decorator in getattr(node, 'decorator_list', []):
with self._scope.start_reference() as scope:
self.visit(decorator)
with self._scope.enter() as scope:
with scope.start_definition():
args = node.args
for arg in [args.kwarg, args.vararg]:
if arg:
# arg is either an "arg" object (Python 3.4+) or a str
scope.define(arg.arg if hasattr(arg, 'arg') else arg)
# kwonlyargs was added in Python 3
for arg in args.args + getattr(args, 'kwonlyargs', []):
scope.define(arg.id if hasattr(arg, 'id') else arg.arg)
for default in args.defaults:
self.visit(default)
body = [node.body] if isinstance(node, ast.Lambda) else node.body
with scope.start_reference():
for statement in body:
self.visit(statement)
def visit_ListComp(self, node):
return self.visit_GeneratorExp(node)
def visit_Print(self, node):
for value in node.values:
with self._scope.start_reference():
self.visit(value)
if node.dest:
with self._scope.start_reference():
self.visit(node.dest)
def visit_GeneratorExp(self, node):
with self._scope.start_reference():
self.visit(node.elt)
for elt in node.generators:
self.visit(elt)
def visit_comprehension(self, node):
with self._scope.start_definition():
self.visit(node.target)
with self._scope.start_reference():
self.visit(node.iter)
for elt in node.ifs:
with self._scope.start_reference():
self.visit(elt)
def visit_Assign(self, node):
for target in node.targets:
with self._scope.start_definition():
self.visit(target)
with self._scope.start_reference():
self.visit(node.value)
def visit_ClassDef(self, node):
for decorator in getattr(node, 'decorator_list', []):
with self._scope.start_reference():
self.visit(decorator)
self._scope.define(node.name)
for base in node.bases:
with self._scope.start_reference():
self.visit(base)
with self._scope.enter(is_class=True):
for body in node.body:
with self._scope.start_reference():
self.visit(body)
def visit_ImportFrom(self, node):
for name in node.names:
if name.name == '*':
# TODO: Do something?
continue
symbol = name.asname or name.name.split('.')[0]
self._scope.define(symbol)
# Explicitly add a reference for __future__ imports so they don't
# get pruned.
if node.module == '__future__':
self._scope.reference(symbol)
self.generic_visit(node)
def visit_Import(self, node):
for name in node.names:
self._scope.define(name.asname or name.name)
self.generic_visit(node)
def visit_With(self, node):
if hasattr(node, 'items'):
for item in node.items:
self._visit_withitem(item)
else:
self._visit_withitem(node)
with self._scope.start_reference():
self.visit(node.body)
def _visit_withitem(self, node):
if node.optional_vars:
with self._scope.start_definition():
self.visit(node.optional_vars)
with self._scope.start_reference():
self.visit(node.context_expr)
def visit_For(self, node):
with self._scope.start_definition():
self.visit(node.target)
with self._scope.start_reference():
self.visit(node.iter)
with self._scope.start_reference():
self.visit(node.body)
with self._scope.start_reference():
self.visit(node.orelse)
def visit_Attribute(self, node, chain=False):
if isinstance(node.value, ast.Name):
self._scope.extend_symbol(node.value.id)
self._scope.extend_symbol(node.attr)
if not chain:
self._scope.end_symbol()
elif isinstance(node.value, ast.Attribute):
self.visit_Attribute(node.value, chain=True)
self._scope.extend_symbol(node.attr, extend_only=True)
else:
self._scope.end_symbol()
self.visit(node.value)
self._scope.end_symbol()
def visit_Subscript(self, node):
self._scope.end_symbol()
with self._scope.start_reference():
self.visit(node.value)
self.visit(node.slice)
def visit_Call(self, node):
with self._scope.start_reference():
self.visit(node.func)
# Python 3.5 AST removed starargs and kwargs
additional = []
if getattr(node, 'starargs', None):
additional.append(node.starargs)
if getattr(node, 'kwargs', None):
additional.append(node.kwargs)
for arg in chain(node.args, node.keywords, additional):
with self._scope.start_reference():
self.visit(arg)
def visit_Name(self, node):
self._scope.extend_symbol(node.id)
self._scope.end_symbol()
if __name__ == '__main__':
with open(sys.argv[1]) as fd:
scope = Scope.from_source(fd.read())
unresolved, unreferenced = scope.find_unresolved_and_unreferenced_symbols()
from pprint import pprint
pprint(unresolved)
pprint(unreferenced)
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