139 lines
4.3 KiB
Python
139 lines
4.3 KiB
Python
|
# Test the most dynamic corner cases of Python's runtime semantics.
|
||
|
|
|
||
|
|
import builtins
|
||
|
|
import unittest
|
||
|
|
|
||
|
|
from test.support import swap_item, swap_attr
|
||
|
|
|
||
|
|
|
||
|
|
class RebindBuiltinsTests(unittest.TestCase):
|
||
|
|
|
||
|
|
"""Test all the ways that we can change/shadow globals/builtins."""
|
||
|
|
|
||
|
|
def configure_func(self, func, *args):
|
||
|
|
"""Perform TestCase-specific configuration on a function before testing.
|
||
|
|
|
||
|
|
By default, this does nothing. Example usage: spinning a function so
|
||
|
|
that a JIT will optimize it. Subclasses should override this as needed.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
func: function to configure.
|
||
|
|
*args: any arguments that should be passed to func, if calling it.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
Nothing. Work will be performed on func in-place.
|
||
|
|
"""
|
||
|
|
pass
|
||
|
|
|
||
|
|
def test_globals_shadow_builtins(self):
|
||
|
|
# Modify globals() to shadow an entry in builtins.
|
||
|
|
def foo():
|
||
|
|
return len([1, 2, 3])
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
self.assertEqual(foo(), 3)
|
||
|
|
with swap_item(globals(), "len", lambda x: 7):
|
||
|
|
self.assertEqual(foo(), 7)
|
||
|
|
|
||
|
|
def test_modify_builtins(self):
|
||
|
|
# Modify the builtins module directly.
|
||
|
|
def foo():
|
||
|
|
return len([1, 2, 3])
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
self.assertEqual(foo(), 3)
|
||
|
|
with swap_attr(builtins, "len", lambda x: 7):
|
||
|
|
self.assertEqual(foo(), 7)
|
||
|
|
|
||
|
|
def test_modify_builtins_while_generator_active(self):
|
||
|
|
# Modify the builtins out from under a live generator.
|
||
|
|
def foo():
|
||
|
|
x = range(3)
|
||
|
|
yield len(x)
|
||
|
|
yield len(x)
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
g = foo()
|
||
|
|
self.assertEqual(next(g), 3)
|
||
|
|
with swap_attr(builtins, "len", lambda x: 7):
|
||
|
|
self.assertEqual(next(g), 7)
|
||
|
|
|
||
|
|
def test_modify_builtins_from_leaf_function(self):
|
||
|
|
# Verify that modifications made by leaf functions percolate up the
|
||
|
|
# callstack.
|
||
|
|
with swap_attr(builtins, "len", len):
|
||
|
|
def bar():
|
||
|
|
builtins.len = lambda x: 4
|
||
|
|
|
||
|
|
def foo(modifier):
|
||
|
|
l = []
|
||
|
|
l.append(len(range(7)))
|
||
|
|
modifier()
|
||
|
|
l.append(len(range(7)))
|
||
|
|
return l
|
||
|
|
self.configure_func(foo, lambda: None)
|
||
|
|
|
||
|
|
self.assertEqual(foo(bar), [7, 4])
|
||
|
|
|
||
|
|
def test_cannot_change_globals_or_builtins_with_eval(self):
|
||
|
|
def foo():
|
||
|
|
return len([1, 2, 3])
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
# Note that this *doesn't* change the definition of len() seen by foo().
|
||
|
|
builtins_dict = {"len": lambda x: 7}
|
||
|
|
globals_dict = {"foo": foo, "__builtins__": builtins_dict,
|
||
|
|
"len": lambda x: 8}
|
||
|
|
self.assertEqual(eval("foo()", globals_dict), 3)
|
||
|
|
|
||
|
|
self.assertEqual(eval("foo()", {"foo": foo}), 3)
|
||
|
|
|
||
|
|
def test_cannot_change_globals_or_builtins_with_exec(self):
|
||
|
|
def foo():
|
||
|
|
return len([1, 2, 3])
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
globals_dict = {"foo": foo}
|
||
|
|
exec("x = foo()", globals_dict)
|
||
|
|
self.assertEqual(globals_dict["x"], 3)
|
||
|
|
|
||
|
|
# Note that this *doesn't* change the definition of len() seen by foo().
|
||
|
|
builtins_dict = {"len": lambda x: 7}
|
||
|
|
globals_dict = {"foo": foo, "__builtins__": builtins_dict,
|
||
|
|
"len": lambda x: 8}
|
||
|
|
|
||
|
|
exec("x = foo()", globals_dict)
|
||
|
|
self.assertEqual(globals_dict["x"], 3)
|
||
|
|
|
||
|
|
def test_cannot_replace_builtins_dict_while_active(self):
|
||
|
|
def foo():
|
||
|
|
x = range(3)
|
||
|
|
yield len(x)
|
||
|
|
yield len(x)
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
g = foo()
|
||
|
|
self.assertEqual(next(g), 3)
|
||
|
|
with swap_item(globals(), "__builtins__", {"len": lambda x: 7}):
|
||
|
|
self.assertEqual(next(g), 3)
|
||
|
|
|
||
|
|
def test_cannot_replace_builtins_dict_between_calls(self):
|
||
|
|
def foo():
|
||
|
|
return len([1, 2, 3])
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
self.assertEqual(foo(), 3)
|
||
|
|
with swap_item(globals(), "__builtins__", {"len": lambda x: 7}):
|
||
|
|
self.assertEqual(foo(), 3)
|
||
|
|
|
||
|
|
def test_eval_gives_lambda_custom_globals(self):
|
||
|
|
globals_dict = {"len": lambda x: 7}
|
||
|
|
foo = eval("lambda: len([])", globals_dict)
|
||
|
|
self.configure_func(foo)
|
||
|
|
|
||
|
|
self.assertEqual(foo(), 7)
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == "__main__":
|
||
|
|
unittest.main()
|