cpython/Lib/test/test_code.py
Guido van Rossum 62bd97303e
Fix a SystemError in code.replace() (#27771)
While the comment said 'We don't bother resizing localspluskinds',
this would cause .replace() to crash when it happened.
(Also types.CodeType(), but testing that is tedious, and this tests all
code paths.)
2021-08-16 11:34:23 -07:00

620 lines
19 KiB
Python

"""This module includes tests of the code object representation.
>>> def f(x):
... def g(y):
... return x + y
... return g
...
>>> dump(f.__code__)
name: f
argcount: 1
posonlyargcount: 0
kwonlyargcount: 0
names: ()
varnames: ('x', 'g')
cellvars: ('x',)
freevars: ()
nlocals: 2
flags: 3
consts: ('None', '<code object g>')
>>> dump(f(4).__code__)
name: g
argcount: 1
posonlyargcount: 0
kwonlyargcount: 0
names: ()
varnames: ('y',)
cellvars: ()
freevars: ('x',)
nlocals: 1
flags: 19
consts: ('None',)
>>> def h(x, y):
... a = x + y
... b = x - y
... c = a * b
... return c
...
>>> dump(h.__code__)
name: h
argcount: 2
posonlyargcount: 0
kwonlyargcount: 0
names: ()
varnames: ('x', 'y', 'a', 'b', 'c')
cellvars: ()
freevars: ()
nlocals: 5
flags: 3
consts: ('None',)
>>> def attrs(obj):
... print(obj.attr1)
... print(obj.attr2)
... print(obj.attr3)
>>> dump(attrs.__code__)
name: attrs
argcount: 1
posonlyargcount: 0
kwonlyargcount: 0
names: ('print', 'attr1', 'attr2', 'attr3')
varnames: ('obj',)
cellvars: ()
freevars: ()
nlocals: 1
flags: 3
consts: ('None',)
>>> def optimize_away():
... 'doc string'
... 'not a docstring'
... 53
... 0x53
>>> dump(optimize_away.__code__)
name: optimize_away
argcount: 0
posonlyargcount: 0
kwonlyargcount: 0
names: ()
varnames: ()
cellvars: ()
freevars: ()
nlocals: 0
flags: 3
consts: ("'doc string'", 'None')
>>> def keywordonly_args(a,b,*,k1):
... return a,b,k1
...
>>> dump(keywordonly_args.__code__)
name: keywordonly_args
argcount: 2
posonlyargcount: 0
kwonlyargcount: 1
names: ()
varnames: ('a', 'b', 'k1')
cellvars: ()
freevars: ()
nlocals: 3
flags: 3
consts: ('None',)
>>> def posonly_args(a,b,/,c):
... return a,b,c
...
>>> dump(posonly_args.__code__)
name: posonly_args
argcount: 3
posonlyargcount: 2
kwonlyargcount: 0
names: ()
varnames: ('a', 'b', 'c')
cellvars: ()
freevars: ()
nlocals: 3
flags: 3
consts: ('None',)
"""
import inspect
import sys
import threading
import unittest
import textwrap
import weakref
try:
import ctypes
except ImportError:
ctypes = None
from test.support import (run_doctest, run_unittest, cpython_only,
check_impl_detail, requires_debug_ranges)
from test.support.script_helper import assert_python_ok
def consts(t):
"""Yield a doctest-safe sequence of object reprs."""
for elt in t:
r = repr(elt)
if r.startswith("<code object"):
yield "<code object %s>" % elt.co_name
else:
yield r
def dump(co):
"""Print out a text representation of a code object."""
for attr in ["name", "argcount", "posonlyargcount",
"kwonlyargcount", "names", "varnames",
"cellvars", "freevars", "nlocals", "flags"]:
print("%s: %s" % (attr, getattr(co, "co_" + attr)))
print("consts:", tuple(consts(co.co_consts)))
# Needed for test_closure_injection below
# Defined at global scope to avoid implicitly closing over __class__
def external_getitem(self, i):
return f"Foreign getitem: {super().__getitem__(i)}"
class CodeTest(unittest.TestCase):
@cpython_only
def test_newempty(self):
import _testcapi
co = _testcapi.code_newempty("filename", "funcname", 15)
self.assertEqual(co.co_filename, "filename")
self.assertEqual(co.co_name, "funcname")
self.assertEqual(co.co_firstlineno, 15)
@cpython_only
def test_closure_injection(self):
# From https://bugs.python.org/issue32176
from types import FunctionType
def create_closure(__class__):
return (lambda: __class__).__closure__
def new_code(c):
'''A new code object with a __class__ cell added to freevars'''
return c.replace(co_freevars=c.co_freevars + ('__class__',))
def add_foreign_method(cls, name, f):
code = new_code(f.__code__)
assert not f.__closure__
closure = create_closure(cls)
defaults = f.__defaults__
setattr(cls, name, FunctionType(code, globals(), name, defaults, closure))
class List(list):
pass
add_foreign_method(List, "__getitem__", external_getitem)
# Ensure the closure injection actually worked
function = List.__getitem__
class_ref = function.__closure__[0].cell_contents
self.assertIs(class_ref, List)
# Ensure the zero-arg super() call in the injected method works
obj = List([1, 2, 3])
self.assertEqual(obj[0], "Foreign getitem: 1")
def test_constructor(self):
def func(): pass
co = func.__code__
CodeType = type(co)
# test code constructor
return CodeType(co.co_argcount,
co.co_posonlyargcount,
co.co_kwonlyargcount,
co.co_nlocals,
co.co_stacksize,
co.co_flags,
co.co_code,
co.co_consts,
co.co_names,
co.co_varnames,
co.co_filename,
co.co_name,
co.co_qualname,
co.co_firstlineno,
co.co_lnotab,
co.co_endlinetable,
co.co_columntable,
co.co_exceptiontable,
co.co_freevars,
co.co_cellvars)
def test_qualname(self):
self.assertEqual(
CodeTest.test_qualname.__code__.co_qualname,
CodeTest.test_qualname.__qualname__
)
def test_replace(self):
def func():
x = 1
return x
code = func.__code__
# different co_name, co_varnames, co_consts
def func2():
y = 2
z = 3
return y
code2 = func2.__code__
for attr, value in (
("co_argcount", 0),
("co_posonlyargcount", 0),
("co_kwonlyargcount", 0),
("co_nlocals", 1),
("co_stacksize", 0),
("co_flags", code.co_flags | inspect.CO_COROUTINE),
("co_firstlineno", 100),
("co_code", code2.co_code),
("co_consts", code2.co_consts),
("co_names", ("myname",)),
("co_varnames", ('spam',)),
("co_freevars", ("freevar",)),
("co_cellvars", ("cellvar",)),
("co_filename", "newfilename"),
("co_name", "newname"),
("co_linetable", code2.co_linetable),
("co_endlinetable", code2.co_endlinetable),
("co_columntable", code2.co_columntable),
):
with self.subTest(attr=attr, value=value):
new_code = code.replace(**{attr: value})
self.assertEqual(getattr(new_code, attr), value)
new_code = code.replace(co_varnames=code2.co_varnames,
co_nlocals=code2.co_nlocals)
self.assertEqual(new_code.co_varnames, code2.co_varnames)
self.assertEqual(new_code.co_nlocals, code2.co_nlocals)
def test_nlocals_mismatch(self):
def func():
x = 1
return x
co = func.__code__
assert co.co_nlocals > 0;
# First we try the constructor.
CodeType = type(co)
for diff in (-1, 1):
with self.assertRaises(ValueError):
CodeType(co.co_argcount,
co.co_posonlyargcount,
co.co_kwonlyargcount,
# This is the only change.
co.co_nlocals + diff,
co.co_stacksize,
co.co_flags,
co.co_code,
co.co_consts,
co.co_names,
co.co_varnames,
co.co_filename,
co.co_name,
co.co_qualname,
co.co_firstlineno,
co.co_lnotab,
co.co_endlinetable,
co.co_columntable,
co.co_exceptiontable,
co.co_freevars,
co.co_cellvars,
)
# Then we try the replace method.
with self.assertRaises(ValueError):
co.replace(co_nlocals=co.co_nlocals - 1)
with self.assertRaises(ValueError):
co.replace(co_nlocals=co.co_nlocals + 1)
def test_shrinking_localsplus(self):
# Check that PyCode_NewWithPosOnlyArgs resizes both
# localsplusnames and localspluskinds, if an argument is a cell.
def func(arg):
return lambda: arg
code = func.__code__
newcode = code.replace(co_name="func") # Should not raise SystemError
self.assertEqual(code, newcode)
def test_empty_linetable(self):
def func():
pass
new_code = code = func.__code__.replace(co_linetable=b'')
self.assertEqual(list(new_code.co_lines()), [])
@requires_debug_ranges()
def test_co_positions_artificial_instructions(self):
import dis
namespace = {}
exec(textwrap.dedent("""\
try:
1/0
except Exception as e:
exc = e
"""), namespace)
exc = namespace['exc']
traceback = exc.__traceback__
code = traceback.tb_frame.f_code
artificial_instructions = []
for instr, positions in zip(
dis.get_instructions(code),
code.co_positions(),
strict=True
):
# If any of the positions is None, then all have to
# be None as well for the case above. There are still
# some places in the compiler, where the artificial instructions
# get assigned the first_lineno but they don't have other positions.
# There is no easy way of inferring them at that stage, so for now
# we don't support it.
self.assertTrue(positions.count(None) in [0, 4])
if not any(positions):
artificial_instructions.append(instr)
self.assertEqual(
[
(instruction.opname, instruction.argval)
for instruction in artificial_instructions
],
[
("PUSH_EXC_INFO", None),
("LOAD_CONST", None), # artificial 'None'
("STORE_NAME", "e"), # XX: we know the location for this
("DELETE_NAME", "e"),
("RERAISE", 1),
("POP_EXCEPT_AND_RERAISE", None)
]
)
def test_endline_and_columntable_none_when_no_debug_ranges(self):
# Make sure that if `-X no_debug_ranges` is used, the endlinetable and
# columntable are None.
code = textwrap.dedent("""
def f():
pass
assert f.__code__.co_endlinetable is None
assert f.__code__.co_columntable is None
""")
assert_python_ok('-X', 'no_debug_ranges', '-c', code)
def test_endline_and_columntable_none_when_no_debug_ranges_env(self):
# Same as above but using the environment variable opt out.
code = textwrap.dedent("""
def f():
pass
assert f.__code__.co_endlinetable is None
assert f.__code__.co_columntable is None
""")
assert_python_ok('-c', code, PYTHONNODEBUGRANGES='1')
# co_positions behavior when info is missing.
@requires_debug_ranges()
def test_co_positions_empty_linetable(self):
def func():
x = 1
new_code = func.__code__.replace(co_linetable=b'')
for line, end_line, column, end_column in new_code.co_positions():
self.assertIsNone(line)
self.assertEqual(end_line, new_code.co_firstlineno + 1)
@requires_debug_ranges()
def test_co_positions_empty_endlinetable(self):
def func():
x = 1
new_code = func.__code__.replace(co_endlinetable=b'')
for line, end_line, column, end_column in new_code.co_positions():
self.assertEqual(line, new_code.co_firstlineno + 1)
self.assertIsNone(end_line)
@requires_debug_ranges()
def test_co_positions_empty_columntable(self):
def func():
x = 1
new_code = func.__code__.replace(co_columntable=b'')
for line, end_line, column, end_column in new_code.co_positions():
self.assertEqual(line, new_code.co_firstlineno + 1)
self.assertEqual(end_line, new_code.co_firstlineno + 1)
self.assertIsNone(column)
self.assertIsNone(end_column)
def isinterned(s):
return s is sys.intern(('_' + s + '_')[1:-1])
class CodeConstsTest(unittest.TestCase):
def find_const(self, consts, value):
for v in consts:
if v == value:
return v
self.assertIn(value, consts) # raises an exception
self.fail('Should never be reached')
def assertIsInterned(self, s):
if not isinterned(s):
self.fail('String %r is not interned' % (s,))
def assertIsNotInterned(self, s):
if isinterned(s):
self.fail('String %r is interned' % (s,))
@cpython_only
def test_interned_string(self):
co = compile('res = "str_value"', '?', 'exec')
v = self.find_const(co.co_consts, 'str_value')
self.assertIsInterned(v)
@cpython_only
def test_interned_string_in_tuple(self):
co = compile('res = ("str_value",)', '?', 'exec')
v = self.find_const(co.co_consts, ('str_value',))
self.assertIsInterned(v[0])
@cpython_only
def test_interned_string_in_frozenset(self):
co = compile('res = a in {"str_value"}', '?', 'exec')
v = self.find_const(co.co_consts, frozenset(('str_value',)))
self.assertIsInterned(tuple(v)[0])
@cpython_only
def test_interned_string_default(self):
def f(a='str_value'):
return a
self.assertIsInterned(f())
@cpython_only
def test_interned_string_with_null(self):
co = compile(r'res = "str\0value!"', '?', 'exec')
v = self.find_const(co.co_consts, 'str\0value!')
self.assertIsNotInterned(v)
class CodeWeakRefTest(unittest.TestCase):
def test_basic(self):
# Create a code object in a clean environment so that we know we have
# the only reference to it left.
namespace = {}
exec("def f(): pass", globals(), namespace)
f = namespace["f"]
del namespace
self.called = False
def callback(code):
self.called = True
# f is now the last reference to the function, and through it, the code
# object. While we hold it, check that we can create a weakref and
# deref it. Then delete it, and check that the callback gets called and
# the reference dies.
coderef = weakref.ref(f.__code__, callback)
self.assertTrue(bool(coderef()))
del f
self.assertFalse(bool(coderef()))
self.assertTrue(self.called)
if check_impl_detail(cpython=True) and ctypes is not None:
py = ctypes.pythonapi
freefunc = ctypes.CFUNCTYPE(None,ctypes.c_voidp)
RequestCodeExtraIndex = py._PyEval_RequestCodeExtraIndex
RequestCodeExtraIndex.argtypes = (freefunc,)
RequestCodeExtraIndex.restype = ctypes.c_ssize_t
SetExtra = py._PyCode_SetExtra
SetExtra.argtypes = (ctypes.py_object, ctypes.c_ssize_t, ctypes.c_voidp)
SetExtra.restype = ctypes.c_int
GetExtra = py._PyCode_GetExtra
GetExtra.argtypes = (ctypes.py_object, ctypes.c_ssize_t,
ctypes.POINTER(ctypes.c_voidp))
GetExtra.restype = ctypes.c_int
LAST_FREED = None
def myfree(ptr):
global LAST_FREED
LAST_FREED = ptr
FREE_FUNC = freefunc(myfree)
FREE_INDEX = RequestCodeExtraIndex(FREE_FUNC)
class CoExtra(unittest.TestCase):
def get_func(self):
# Defining a function causes the containing function to have a
# reference to the code object. We need the code objects to go
# away, so we eval a lambda.
return eval('lambda:42')
def test_get_non_code(self):
f = self.get_func()
self.assertRaises(SystemError, SetExtra, 42, FREE_INDEX,
ctypes.c_voidp(100))
self.assertRaises(SystemError, GetExtra, 42, FREE_INDEX,
ctypes.c_voidp(100))
def test_bad_index(self):
f = self.get_func()
self.assertRaises(SystemError, SetExtra, f.__code__,
FREE_INDEX+100, ctypes.c_voidp(100))
self.assertEqual(GetExtra(f.__code__, FREE_INDEX+100,
ctypes.c_voidp(100)), 0)
def test_free_called(self):
# Verify that the provided free function gets invoked
# when the code object is cleaned up.
f = self.get_func()
SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(100))
del f
self.assertEqual(LAST_FREED, 100)
def test_get_set(self):
# Test basic get/set round tripping.
f = self.get_func()
extra = ctypes.c_voidp()
SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(200))
# reset should free...
SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(300))
self.assertEqual(LAST_FREED, 200)
extra = ctypes.c_voidp()
GetExtra(f.__code__, FREE_INDEX, extra)
self.assertEqual(extra.value, 300)
del f
def test_free_different_thread(self):
# Freeing a code object on a different thread then
# where the co_extra was set should be safe.
f = self.get_func()
class ThreadTest(threading.Thread):
def __init__(self, f, test):
super().__init__()
self.f = f
self.test = test
def run(self):
del self.f
self.test.assertEqual(LAST_FREED, 500)
SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(500))
tt = ThreadTest(f, self)
del f
tt.start()
tt.join()
self.assertEqual(LAST_FREED, 500)
def test_main(verbose=None):
from test import test_code
run_doctest(test_code, verbose)
tests = [CodeTest, CodeConstsTest, CodeWeakRefTest]
if check_impl_detail(cpython=True) and ctypes is not None:
tests.append(CoExtra)
run_unittest(*tests)
if __name__ == "__main__":
test_main()