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Fix inconsistent used-before-assignment for partial bindings (#10975)
Signed-off-by: Emmanuel Ferdman <[email protected]>
1 parent 0e3b9eb commit b080a21

7 files changed

Lines changed: 59 additions & 41 deletions

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‎doc/whatsnew/fragments/9879.false_positive‎

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Fix ``used-before-assignment`` false positive for names bound in only some arms of an ``if/elif/else`` chain.
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Closes #9879

‎pylint/checkers/variables.py‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -740,10 +740,10 @@ def _inferred_to_define_name_raise_or_return_for_if_node(
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# Search both if and else branches
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if_branch_handles = self._branch_handles_name(name, node.body)
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else_branch_handles = self._branch_handles_name(name, node.orelse)
743-
if if_branch_handles ^ else_branch_handles:
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if if_branch_handles and else_branch_handles:
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self.names_defined_under_one_branch_only.discard(name)
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elif if_branch_handles ^ else_branch_handles:
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self.names_defined_under_one_branch_only.add(name)
745-
elif name in self.names_defined_under_one_branch_only:
746-
self.names_defined_under_one_branch_only.remove(name)
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return if_branch_handles and else_branch_handles
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def _branch_handles_name(self, name: str, body: Iterable[nodes.NodeNG]) -> bool:

‎tests/functional/r/regression_02/regression_9879.py‎

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"""Regression test for https://github.com/pylint-dev/pylint/issues/9879"""
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# pylint: disable=missing-function-docstring
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def func(mode):
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if mode == "a":
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pass
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elif mode == "b":
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x = 1
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elif mode == "c":
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pass
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else:
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assert False
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print(x) # [possibly-used-before-assignment]

‎tests/functional/r/regression_02/regression_9879.txt‎

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possibly-used-before-assignment:14:10:14:11:func:Possibly using variable 'x' before assignment:CONTROL_FLOW

‎tests/functional/u/used/used_before_assignment_typing.314.txt‎

Lines changed: 11 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -1,15 +1,15 @@
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undefined-variable:79:20:79:27:MyClass.incorrect_default_method:Undefined variable 'MyClass':UNDEFINED
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possibly-used-before-assignment:171:14:171:20:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'bisect' before assignment:INFERENCE
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possibly-used-before-assignment:172:15:172:23:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'calendar' before assignment:INFERENCE
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used-before-assignment:175:14:175:22:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'zoneinfo' before assignment:INFERENCE
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used-before-assignment:176:14:176:20:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'pprint' before assignment:INFERENCE
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used-before-assignment:177:14:177:25:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'collections' before assignment:INFERENCE
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possibly-used-before-assignment:175:14:175:22:TypeCheckingMultiBranch.defined_in_else_branch:Possibly using variable 'zoneinfo' before assignment:INFERENCE
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possibly-used-before-assignment:176:14:176:20:TypeCheckingMultiBranch.defined_in_else_branch:Possibly using variable 'pprint' before assignment:INFERENCE
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possibly-used-before-assignment:177:14:177:25:TypeCheckingMultiBranch.defined_in_else_branch:Possibly using variable 'collections' before assignment:INFERENCE
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possibly-used-before-assignment:181:14:181:19:TypeCheckingMultiBranch.defined_in_nested_if_else:Possibly using variable 'heapq' before assignment:INFERENCE
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used-before-assignment:185:14:185:19:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'types' before assignment:INFERENCE
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used-before-assignment:186:14:186:18:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'copy' before assignment:INFERENCE
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used-before-assignment:187:14:187:21:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'numbers' before assignment:INFERENCE
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used-before-assignment:188:15:188:20:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'array' before assignment:INFERENCE
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used-before-assignment:191:14:191:19:TypeCheckingMultiBranch.defined_in_loops:Using variable 'email' before assignment:INFERENCE
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used-before-assignment:192:14:192:21:TypeCheckingMultiBranch.defined_in_loops:Using variable 'mailbox' before assignment:INFERENCE
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used-before-assignment:193:14:193:23:TypeCheckingMultiBranch.defined_in_loops:Using variable 'mimetypes' before assignment:INFERENCE
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used-before-assignment:197:14:197:22:TypeCheckingMultiBranch.defined_in_with:Using variable 'binascii' before assignment:INFERENCE
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possibly-used-before-assignment:185:14:185:19:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'types' before assignment:INFERENCE
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possibly-used-before-assignment:186:14:186:18:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'copy' before assignment:INFERENCE
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possibly-used-before-assignment:187:14:187:21:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'numbers' before assignment:INFERENCE
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possibly-used-before-assignment:188:15:188:20:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'array' before assignment:INFERENCE
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possibly-used-before-assignment:191:14:191:19:TypeCheckingMultiBranch.defined_in_loops:Possibly using variable 'email' before assignment:INFERENCE
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possibly-used-before-assignment:192:14:192:21:TypeCheckingMultiBranch.defined_in_loops:Possibly using variable 'mailbox' before assignment:INFERENCE
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possibly-used-before-assignment:193:14:193:23:TypeCheckingMultiBranch.defined_in_loops:Possibly using variable 'mimetypes' before assignment:INFERENCE
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possibly-used-before-assignment:197:14:197:22:TypeCheckingMultiBranch.defined_in_with:Possibly using variable 'binascii' before assignment:INFERENCE

‎tests/functional/u/used/used_before_assignment_typing.py‎

Lines changed: 14 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -172,29 +172,29 @@ def defined_in_elif_branch(self) -> calendar.Calendar: # <3.14:[possibly-used-b
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return calendar.Calendar() # >=3.14:[possibly-used-before-assignment]
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def defined_in_else_branch(self) -> urlopen:
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print(zoneinfo) # [used-before-assignment]
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print(pprint()) # [used-before-assignment]
177-
print(collections()) # [used-before-assignment]
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print(zoneinfo) # [possibly-used-before-assignment]
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print(pprint()) # [possibly-used-before-assignment]
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print(collections()) # [possibly-used-before-assignment]
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return urlopen
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def defined_in_nested_if_else(self) -> heapq: # <3.14:[possibly-used-before-assignment]
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print(heapq) # >=3.14:[possibly-used-before-assignment]
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return heapq
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184-
def defined_in_try_except(self) -> array: # <3.14:[used-before-assignment]
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print(types) # [used-before-assignment]
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print(copy) # [used-before-assignment]
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print(numbers) # [used-before-assignment]
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return array # >=3.14:[used-before-assignment]
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def defined_in_try_except(self) -> array: # <3.14:[possibly-used-before-assignment]
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print(types) # [possibly-used-before-assignment]
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print(copy) # [possibly-used-before-assignment]
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print(numbers) # [possibly-used-before-assignment]
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return array # >=3.14:[possibly-used-before-assignment]
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190-
def defined_in_loops(self) -> json: # <3.14:[used-before-assignment]
191-
print(email) # [used-before-assignment]
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print(mailbox) # [used-before-assignment]
193-
print(mimetypes) # [used-before-assignment]
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def defined_in_loops(self) -> json: # <3.14:[possibly-used-before-assignment]
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print(email) # [possibly-used-before-assignment]
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print(mailbox) # [possibly-used-before-assignment]
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print(mimetypes) # [possibly-used-before-assignment]
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return json
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196-
def defined_in_with(self) -> base64: # <3.14:[used-before-assignment]
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print(binascii) # [used-before-assignment]
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def defined_in_with(self) -> base64: # <3.14:[possibly-used-before-assignment]
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print(binascii) # [possibly-used-before-assignment]
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return base64
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‎tests/functional/u/used/used_before_assignment_typing.txt‎

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Original file line numberDiff line numberDiff line change
@@ -5,17 +5,17 @@ used-before-assignment:140:35:140:39:MyFourthClass.is_close:Using variable 'math
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used-before-assignment:153:20:153:28:VariableAnnotationsGuardedByTypeChecking:Using variable 'datetime' before assignment:INFERENCE
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possibly-used-before-assignment:170:40:170:48:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'calendar' before assignment:INFERENCE
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possibly-used-before-assignment:171:14:171:20:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'bisect' before assignment:INFERENCE
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used-before-assignment:175:14:175:22:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'zoneinfo' before assignment:INFERENCE
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used-before-assignment:176:14:176:20:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'pprint' before assignment:INFERENCE
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used-before-assignment:177:14:177:25:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'collections' before assignment:INFERENCE
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possibly-used-before-assignment:175:14:175:22:TypeCheckingMultiBranch.defined_in_else_branch:Possibly using variable 'zoneinfo' before assignment:INFERENCE
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possibly-used-before-assignment:176:14:176:20:TypeCheckingMultiBranch.defined_in_else_branch:Possibly using variable 'pprint' before assignment:INFERENCE
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possibly-used-before-assignment:177:14:177:25:TypeCheckingMultiBranch.defined_in_else_branch:Possibly using variable 'collections' before assignment:INFERENCE
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possibly-used-before-assignment:180:43:180:48:TypeCheckingMultiBranch.defined_in_nested_if_else:Possibly using variable 'heapq' before assignment:INFERENCE
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used-before-assignment:184:39:184:44:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'array' before assignment:INFERENCE
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used-before-assignment:185:14:185:19:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'types' before assignment:INFERENCE
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used-before-assignment:186:14:186:18:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'copy' before assignment:INFERENCE
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used-before-assignment:187:14:187:21:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'numbers' before assignment:INFERENCE
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used-before-assignment:190:34:190:38:TypeCheckingMultiBranch.defined_in_loops:Using variable 'json' before assignment:INFERENCE
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used-before-assignment:191:14:191:19:TypeCheckingMultiBranch.defined_in_loops:Using variable 'email' before assignment:INFERENCE
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used-before-assignment:192:14:192:21:TypeCheckingMultiBranch.defined_in_loops:Using variable 'mailbox' before assignment:INFERENCE
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used-before-assignment:193:14:193:23:TypeCheckingMultiBranch.defined_in_loops:Using variable 'mimetypes' before assignment:INFERENCE
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used-before-assignment:196:33:196:39:TypeCheckingMultiBranch.defined_in_with:Using variable 'base64' before assignment:INFERENCE
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used-before-assignment:197:14:197:22:TypeCheckingMultiBranch.defined_in_with:Using variable 'binascii' before assignment:INFERENCE
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possibly-used-before-assignment:184:39:184:44:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'array' before assignment:INFERENCE
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possibly-used-before-assignment:185:14:185:19:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'types' before assignment:INFERENCE
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possibly-used-before-assignment:186:14:186:18:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'copy' before assignment:INFERENCE
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possibly-used-before-assignment:187:14:187:21:TypeCheckingMultiBranch.defined_in_try_except:Possibly using variable 'numbers' before assignment:INFERENCE
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possibly-used-before-assignment:190:34:190:38:TypeCheckingMultiBranch.defined_in_loops:Possibly using variable 'json' before assignment:INFERENCE
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possibly-used-before-assignment:191:14:191:19:TypeCheckingMultiBranch.defined_in_loops:Possibly using variable 'email' before assignment:INFERENCE
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possibly-used-before-assignment:192:14:192:21:TypeCheckingMultiBranch.defined_in_loops:Possibly using variable 'mailbox' before assignment:INFERENCE
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possibly-used-before-assignment:193:14:193:23:TypeCheckingMultiBranch.defined_in_loops:Possibly using variable 'mimetypes' before assignment:INFERENCE
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possibly-used-before-assignment:196:33:196:39:TypeCheckingMultiBranch.defined_in_with:Possibly using variable 'base64' before assignment:INFERENCE
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possibly-used-before-assignment:197:14:197:22:TypeCheckingMultiBranch.defined_in_with:Possibly using variable 'binascii' before assignment:INFERENCE

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