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Flag unidiomatic-typecheck for type(x) is type(y) #10372

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f4eeff2
flag unidiomatic-typecheck for type(x) is type(y)
alexprabhat99 May 6, 2025
ec62635
added changelog
alexprabhat99 May 6, 2025
a1e7e36
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] May 6, 2025
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3 changes: 3 additions & 0 deletions doc/whatsnew/fragments/10365.bugfix
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Fixed unidiomatic-typecheck not flagged for type(x) is type(y).

Closes #10365
11 changes: 0 additions & 11 deletions pylint/checkers/base/comparison_checker.py
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Original file line number Diff line number Diff line change
Expand Up @@ -338,15 +338,4 @@ def _check_type_x_is_y(
):
return

if _is_one_arg_pos_call(right):
right_func = utils.safe_infer(right.func)
if (
isinstance(right_func, nodes.ClassDef)
and right_func.qname() == TYPE_QNAME
):
# type(x) == type(a)
right_arg = utils.safe_infer(right.args[0])
if not isinstance(right_arg, LITERAL_NODE_TYPES):
# not e.g. type(x) == type([])
return
self.add_message("unidiomatic-typecheck", node=node)
16 changes: 8 additions & 8 deletions tests/functional/u/unidiomatic_typecheck.py
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Expand Up @@ -63,14 +63,14 @@ def parameter_shadowing_inference_negatives(type):


def deliberate_subclass_check_negatives(a, b):
type(42) is type(b)
type(42) is not type(b)
type(42) == type(b)
type(42) != type(b)
type(a) is type(b)
type(a) is not type(b)
type(a) == type(b)
type(a) != type(b)
type(42) is type(b) # [unidiomatic-typecheck]
type(42) is not type(b) # [unidiomatic-typecheck]
type(42) == type(b) # [unidiomatic-typecheck]
type(42) != type(b) # [unidiomatic-typecheck]
type(a) is type(b) # [unidiomatic-typecheck]
type(a) is not type(b) # [unidiomatic-typecheck]
type(a) == type(b) # [unidiomatic-typecheck]
type(a) != type(b) # [unidiomatic-typecheck]


def type_of_literals_positives(a):
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8 changes: 8 additions & 0 deletions tests/functional/u/unidiomatic_typecheck.txt
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Expand Up @@ -10,6 +10,14 @@ unidiomatic-typecheck:16:4:16:20:simple_inference_positives:Use isinstance() rat
unidiomatic-typecheck:17:4:17:24:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:18:4:18:20:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:19:4:19:20:simple_inference_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:66:4:66:23:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:67:4:67:27:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:68:4:68:23:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:69:4:69:23:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:70:4:70:22:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:71:4:71:26:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:72:4:72:22:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:73:4:73:22:deliberate_subclass_check_negatives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:77:4:77:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:78:4:78:27:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
unidiomatic-typecheck:79:4:79:23:type_of_literals_positives:Use isinstance() rather than type() for a typecheck.:UNDEFINED
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