430 lines
12 KiB
Python
430 lines
12 KiB
Python
"""This module includes tests of the code object representation.
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>>> def f(x):
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... def g(y):
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... return x + y
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... return g
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...
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>>> dump(f.__code__)
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name: f
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argcount: 1
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posonlyargcount: 0
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kwonlyargcount: 0
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names: ()
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varnames: ('x', 'g')
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cellvars: ('x',)
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freevars: ()
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nlocals: 2
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flags: 3
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consts: ('None', '<code object g>', "'f.<locals>.g'")
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>>> dump(f(4).__code__)
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name: g
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argcount: 1
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posonlyargcount: 0
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kwonlyargcount: 0
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names: ()
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varnames: ('y',)
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cellvars: ()
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freevars: ('x',)
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nlocals: 1
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flags: 19
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consts: ('None',)
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>>> def h(x, y):
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... a = x + y
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... b = x - y
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... c = a * b
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... return c
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...
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>>> dump(h.__code__)
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name: h
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argcount: 2
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posonlyargcount: 0
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kwonlyargcount: 0
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names: ()
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varnames: ('x', 'y', 'a', 'b', 'c')
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cellvars: ()
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freevars: ()
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nlocals: 5
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flags: 67
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consts: ('None',)
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>>> def attrs(obj):
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... print(obj.attr1)
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... print(obj.attr2)
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... print(obj.attr3)
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>>> dump(attrs.__code__)
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name: attrs
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argcount: 1
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posonlyargcount: 0
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kwonlyargcount: 0
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names: ('print', 'attr1', 'attr2', 'attr3')
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varnames: ('obj',)
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cellvars: ()
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freevars: ()
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nlocals: 1
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flags: 67
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consts: ('None',)
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>>> def optimize_away():
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... 'doc string'
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... 'not a docstring'
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... 53
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... 0x53
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>>> dump(optimize_away.__code__)
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name: optimize_away
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argcount: 0
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posonlyargcount: 0
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kwonlyargcount: 0
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names: ()
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varnames: ()
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cellvars: ()
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freevars: ()
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nlocals: 0
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flags: 67
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consts: ("'doc string'", 'None')
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>>> def keywordonly_args(a,b,*,k1):
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... return a,b,k1
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...
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>>> dump(keywordonly_args.__code__)
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name: keywordonly_args
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argcount: 2
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posonlyargcount: 0
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kwonlyargcount: 1
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names: ()
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varnames: ('a', 'b', 'k1')
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cellvars: ()
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freevars: ()
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nlocals: 3
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flags: 67
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consts: ('None',)
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>>> def posonly_args(a,b,/,c):
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... return a,b,c
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...
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>>> dump(posonly_args.__code__)
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name: posonly_args
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argcount: 1
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posonlyargcount: 2
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kwonlyargcount: 0
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names: ()
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varnames: ('a', 'b', 'c')
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cellvars: ()
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freevars: ()
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nlocals: 3
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flags: 67
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consts: ('None',)
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"""
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import inspect
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import sys
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import threading
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import unittest
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import weakref
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import opcode
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try:
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import ctypes
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except ImportError:
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ctypes = None
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from test.support import (run_doctest, run_unittest, cpython_only,
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check_impl_detail)
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def consts(t):
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"""Yield a doctest-safe sequence of object reprs."""
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for elt in t:
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r = repr(elt)
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if r.startswith("<code object"):
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yield "<code object %s>" % elt.co_name
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else:
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yield r
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def dump(co):
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"""Print out a text representation of a code object."""
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for attr in ["name", "argcount", "posonlyargcount",
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"kwonlyargcount", "names", "varnames",
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"cellvars", "freevars", "nlocals", "flags"]:
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print("%s: %s" % (attr, getattr(co, "co_" + attr)))
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print("consts:", tuple(consts(co.co_consts)))
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# Needed for test_closure_injection below
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# Defined at global scope to avoid implicitly closing over __class__
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def external_getitem(self, i):
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return f"Foreign getitem: {super().__getitem__(i)}"
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class CodeTest(unittest.TestCase):
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@cpython_only
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def test_newempty(self):
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import _testcapi
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co = _testcapi.code_newempty("filename", "funcname", 15)
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self.assertEqual(co.co_filename, "filename")
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self.assertEqual(co.co_name, "funcname")
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self.assertEqual(co.co_firstlineno, 15)
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@cpython_only
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def test_closure_injection(self):
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# From https://bugs.python.org/issue32176
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from types import FunctionType, CodeType
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def create_closure(__class__):
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return (lambda: __class__).__closure__
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def new_code(c):
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'''A new code object with a __class__ cell added to freevars'''
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return CodeType(
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c.co_argcount, c.co_posonlyargcount, c.co_kwonlyargcount, c.co_nlocals,
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c.co_stacksize, c.co_flags, c.co_code, c.co_consts, c.co_names,
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c.co_varnames, c.co_filename, c.co_name, c.co_firstlineno,
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c.co_lnotab, c.co_freevars + ('__class__',), c.co_cellvars)
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def add_foreign_method(cls, name, f):
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code = new_code(f.__code__)
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assert not f.__closure__
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closure = create_closure(cls)
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defaults = f.__defaults__
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setattr(cls, name, FunctionType(code, globals(), name, defaults, closure))
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class List(list):
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pass
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add_foreign_method(List, "__getitem__", external_getitem)
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# Ensure the closure injection actually worked
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function = List.__getitem__
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class_ref = function.__closure__[0].cell_contents
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self.assertIs(class_ref, List)
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# Ensure the code correctly indicates it accesses a free variable
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self.assertFalse(function.__code__.co_flags & inspect.CO_NOFREE,
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hex(function.__code__.co_flags))
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# Ensure the zero-arg super() call in the injected method works
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obj = List([1, 2, 3])
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self.assertEqual(obj[0], "Foreign getitem: 1")
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def isinterned(s):
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return s is sys.intern(('_' + s + '_')[1:-1])
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class CodeConstsTest(unittest.TestCase):
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def find_const(self, consts, value):
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for v in consts:
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if v == value:
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return v
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self.assertIn(value, consts) # raises an exception
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self.fail('Should never be reached')
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def assertIsInterned(self, s):
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if not isinterned(s):
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self.fail('String %r is not interned' % (s,))
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def assertIsNotInterned(self, s):
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if isinterned(s):
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self.fail('String %r is interned' % (s,))
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@cpython_only
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def test_interned_string(self):
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co = compile('res = "str_value"', '?', 'exec')
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v = self.find_const(co.co_consts, 'str_value')
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self.assertIsInterned(v)
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@cpython_only
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def test_interned_string_in_tuple(self):
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co = compile('res = ("str_value",)', '?', 'exec')
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v = self.find_const(co.co_consts, ('str_value',))
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self.assertIsInterned(v[0])
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@cpython_only
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def test_interned_string_in_frozenset(self):
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co = compile('res = a in {"str_value"}', '?', 'exec')
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v = self.find_const(co.co_consts, frozenset(('str_value',)))
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self.assertIsInterned(tuple(v)[0])
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@cpython_only
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def test_interned_string_default(self):
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def f(a='str_value'):
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return a
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self.assertIsInterned(f())
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@cpython_only
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def test_interned_string_with_null(self):
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co = compile(r'res = "str\0value!"', '?', 'exec')
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v = self.find_const(co.co_consts, 'str\0value!')
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self.assertIsNotInterned(v)
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class CodeWeakRefTest(unittest.TestCase):
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def test_basic(self):
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# Create a code object in a clean environment so that we know we have
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# the only reference to it left.
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namespace = {}
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exec("def f(): pass", globals(), namespace)
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f = namespace["f"]
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del namespace
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self.called = False
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def callback(code):
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self.called = True
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# f is now the last reference to the function, and through it, the code
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# object. While we hold it, check that we can create a weakref and
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# deref it. Then delete it, and check that the callback gets called and
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# the reference dies.
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coderef = weakref.ref(f.__code__, callback)
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self.assertTrue(bool(coderef()))
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del f
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self.assertFalse(bool(coderef()))
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self.assertTrue(self.called)
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if check_impl_detail(cpython=True) and ctypes is not None:
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py = ctypes.pythonapi
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freefunc = ctypes.CFUNCTYPE(None,ctypes.c_voidp)
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RequestCodeExtraIndex = py._PyEval_RequestCodeExtraIndex
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RequestCodeExtraIndex.argtypes = (freefunc,)
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RequestCodeExtraIndex.restype = ctypes.c_ssize_t
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SetExtra = py._PyCode_SetExtra
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SetExtra.argtypes = (ctypes.py_object, ctypes.c_ssize_t, ctypes.c_voidp)
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SetExtra.restype = ctypes.c_int
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GetExtra = py._PyCode_GetExtra
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GetExtra.argtypes = (ctypes.py_object, ctypes.c_ssize_t,
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ctypes.POINTER(ctypes.c_voidp))
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GetExtra.restype = ctypes.c_int
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LAST_FREED = None
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def myfree(ptr):
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global LAST_FREED
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LAST_FREED = ptr
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FREE_FUNC = freefunc(myfree)
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FREE_INDEX = RequestCodeExtraIndex(FREE_FUNC)
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class CoExtra(unittest.TestCase):
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def get_func(self):
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# Defining a function causes the containing function to have a
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# reference to the code object. We need the code objects to go
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# away, so we eval a lambda.
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return eval('lambda:42')
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def test_get_non_code(self):
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f = self.get_func()
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self.assertRaises(SystemError, SetExtra, 42, FREE_INDEX,
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ctypes.c_voidp(100))
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self.assertRaises(SystemError, GetExtra, 42, FREE_INDEX,
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ctypes.c_voidp(100))
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def test_bad_index(self):
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f = self.get_func()
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self.assertRaises(SystemError, SetExtra, f.__code__,
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FREE_INDEX+100, ctypes.c_voidp(100))
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self.assertEqual(GetExtra(f.__code__, FREE_INDEX+100,
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ctypes.c_voidp(100)), 0)
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def test_free_called(self):
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# Verify that the provided free function gets invoked
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# when the code object is cleaned up.
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f = self.get_func()
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SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(100))
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del f
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self.assertEqual(LAST_FREED, 100)
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def test_get_set(self):
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# Test basic get/set round tripping.
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f = self.get_func()
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extra = ctypes.c_voidp()
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SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(200))
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# reset should free...
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SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(300))
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self.assertEqual(LAST_FREED, 200)
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extra = ctypes.c_voidp()
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GetExtra(f.__code__, FREE_INDEX, extra)
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self.assertEqual(extra.value, 300)
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del f
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def test_free_different_thread(self):
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# Freeing a code object on a different thread then
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# where the co_extra was set should be safe.
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f = self.get_func()
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class ThreadTest(threading.Thread):
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def __init__(self, f, test):
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super().__init__()
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self.f = f
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self.test = test
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def run(self):
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del self.f
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self.test.assertEqual(LAST_FREED, 500)
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SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(500))
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tt = ThreadTest(f, self)
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del f
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tt.start()
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tt.join()
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self.assertEqual(LAST_FREED, 500)
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@cpython_only
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def test_clean_stack_on_return(self):
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def f(x):
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return x
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code = f.__code__
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ct = type(f.__code__)
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# Insert an extra LOAD_FAST, this duplicates the value of
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# 'x' in the stack, leaking it if the frame is not properly
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# cleaned up upon exit.
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bytecode = list(code.co_code)
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bytecode.insert(-2, opcode.opmap['LOAD_FAST'])
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bytecode.insert(-2, 0)
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c = ct(code.co_argcount, code.co_posonlyargcount,
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code.co_kwonlyargcount, code.co_nlocals, code.co_stacksize+1,
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code.co_flags, bytes(bytecode),
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code.co_consts, code.co_names, code.co_varnames,
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code.co_filename, code.co_name, code.co_firstlineno,
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code.co_lnotab, code.co_freevars, code.co_cellvars)
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new_function = type(f)(c, f.__globals__, 'nf', f.__defaults__, f.__closure__)
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class Var:
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pass
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the_object = Var()
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var = weakref.ref(the_object)
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new_function(the_object)
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# Check if the_object is leaked
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del the_object
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assert var() is None
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def test_main(verbose=None):
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from test import test_code
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run_doctest(test_code, verbose)
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tests = [CodeTest, CodeConstsTest, CodeWeakRefTest]
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if check_impl_detail(cpython=True) and ctypes is not None:
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tests.append(CoExtra)
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run_unittest(*tests)
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if __name__ == "__main__":
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test_main()
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