mirror of
https://github.com/github/codeql.git
synced 2026-01-30 14:52:57 +01:00
47 lines
1.6 KiB
Plaintext
47 lines
1.6 KiB
Plaintext
/**
|
|
* @name Inconsistent equality and hashing
|
|
* @description Defining equality for a class without also defining hashability (or vice-versa) violates the object model.
|
|
* @kind problem
|
|
* @tags reliability
|
|
* correctness
|
|
* external/cwe/cwe-581
|
|
* @problem.severity warning
|
|
* @sub-severity high
|
|
* @precision very-high
|
|
* @id py/equals-hash-mismatch
|
|
*/
|
|
|
|
import python
|
|
|
|
FunctionObject defines_equality(ClassObject c, string name) {
|
|
(name = "__eq__" or major_version() = 2 and name = "__cmp__")
|
|
and
|
|
result = c.declaredAttribute(name)
|
|
}
|
|
|
|
FunctionObject implemented_method(ClassObject c, string name) {
|
|
result = defines_equality(c, name)
|
|
or
|
|
result = c.declaredAttribute("__hash__") and name = "__hash__"
|
|
}
|
|
|
|
string unimplemented_method(ClassObject c) {
|
|
not exists(defines_equality(c, _)) and
|
|
(result = "__eq__" and major_version() = 3 or major_version() = 2 and result = "__eq__ or __cmp__")
|
|
or
|
|
/* Python 3 automatically makes classes unhashable if __eq__ is defined, but __hash__ is not */
|
|
not c.declaresAttribute(result) and result = "__hash__" and major_version() = 2
|
|
}
|
|
|
|
predicate violates_hash_contract(ClassObject c, string present, string missing, Object method) {
|
|
not c.unhashable() and
|
|
missing = unimplemented_method(c) and
|
|
method = implemented_method(c, present) and
|
|
not c.unknowableAttributes()
|
|
}
|
|
|
|
from ClassObject c, string present, string missing, FunctionObject method
|
|
where violates_hash_contract(c, present, missing, method) and
|
|
exists(c.getPyClass()) // Suppress results that aren't from source
|
|
select method, "Class $@ implements " + present + " but does not define " + missing + ".", c, c.getName()
|