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# pylint: disable=unnecessary-comprehension,missing-docstring,too-few-public-methods,unnecessary-direct-lambda-call
"""Tests for loopvar-in-closure."""
from enum import Enum
def good_case():
"""No problems here."""
lst = []
for i in range(10):
lst.append(i)
def good_case2():
"""No problems here."""
return [i for i in range(10)]
def good_case3():
"""No problems here."""
lst = []
for i in range(10):
lst.append(lambda i=i: i)
def good_case4():
"""No problems here."""
lst = []
for i in range(10):
print(i)
lst.append(lambda i: i)
def good_case5():
"""No problems here."""
return (i for i in range(10))
def good_case6():
"""Accept use of the variable inside return."""
for i in range(10):
if i == 8:
return lambda: i
return lambda: -1
def good_case7():
"""Lambda defined and called in loop."""
for i in range(10):
print((lambda x: i + x)(1))
def good_case8():
"""Another eager binding of the cell variable."""
funs = []
for i in range(10):
def func(bound_i=i):
"""Ignore."""
return bound_i
funs.append(func)
return funs
def good_case9():
"""Ignore when the cell var is not defined in a loop"""
i = 10
lst = []
for _ in range(10):
lst.append(lambda: i)
return lst
def good_case10():
"""Ignore when a loop variable is shadowed by an inner function"""
lst = []
for i in range(10): # pylint: disable=unused-variable
def func():
i = 100
def func2(arg=i):
return arg
return func2
lst.append(func)
return lst
def good_case_issue3107():
"""Eager binding of cell variable when used in a non-trivial default argument expression.
"""
for i in [[2], [3]]:
next(filter(lambda j, ix=i[0]: j == ix, [1, 3]))
def good_case_issue_5012():
"""Eager binding of cell variable when used as the default value of a keyword-only argument.
https://github.com/PyCQA/pylint/issues/5012
"""
funs = []
for i in range(5):
def func(*, _i=i):
print(_i)
funs.append(func)
def func2(_i=i):
print(_i)
funs.append(func2)
return funs
def bad_case():
"""Closing over a loop variable."""
lst = []
for i in range(10):
print(i)
lst.append(lambda: i) # [cell-var-from-loop]
def bad_case2():
"""Closing over a loop variable."""
return [lambda: i for i in range(10)] # [cell-var-from-loop]
def bad_case3():
"""Closing over variable defined in loop."""
lst = []
for i in range(10):
j = i * i
lst.append(lambda: j) # [cell-var-from-loop]
return lst
def bad_case4():
"""Closing over variable defined in loop."""
lst = []
for i in range(10):
def nested():
"""Nested function."""
return i**2 # [cell-var-from-loop]
lst.append(nested)
return lst
def bad_case5():
"""Problematic case.
If this function is used as
>>> [x() for x in bad_case5()]
it behaves 'as expected', i.e. the result is range(10).
If it's used with
>>> lst = list(bad_case5())
>>> [x() for x in lst]
the result is [9] * 10 again.
"""
return (lambda: i for i in range(10)) # [cell-var-from-loop]
def bad_case6():
"""Closing over variable defined in loop."""
lst = []
for i, j in zip(range(10), range(10, 20)):
print(j)
lst.append(lambda: i) # [cell-var-from-loop]
return lst
def bad_case7():
"""Multiple variables unpacked in comprehension."""
return [
lambda: (
x # [cell-var-from-loop]
+ y) # [cell-var-from-loop]
for x, y in ((1, 2), (3, 4), (5, 6))
]
def bad_case8():
"""Closing over variable defined in loop below the function."""
lst = []
for i in range(10):
lst.append(lambda: j) # [cell-var-from-loop]
j = i * i
return lst
def bad_case9():
"""Detect when loop variable shadows an outer assignment."""
lst = []
i = 100
for i in range(10):
lst.append(lambda: i) # [cell-var-from-loop]
return lst
def bad_case10():
"""Detect when a loop variable is the default argument for a nested function"""
lst = []
for i in range(10):
def func():
def func2(arg=i): # [cell-var-from-loop]
return arg
return func2
lst.append(func)
return lst
def bad_case_issue2846():
"""Closing over variable that is used within a comprehension in the function body."""
lst_a = [
(lambda: n) # [cell-var-from-loop]
for n in range(3)
]
lst_b = [
(lambda: [n for _ in range(3)]) # [cell-var-from-loop]
for n in range(3)
]
return lst_a, lst_b
class Test(Enum):
TEST = (40, 160)
@staticmethod
def new_test(minimum=TEST[0], maximum=TEST[1]):
return minimum, maximum
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