Python: Port InconsistentMRO.ql

For this one we actually lose a test result. However, this is kind of to
be expected since we no longer have the "precise" MRO that the points-to
analysis computes.

Honestly, I'm on the fence about even keeping this query at all. It
seems like it might be superfluous in a world with good Python type
checking.
This commit is contained in:
Taus
2026-02-20 15:29:48 +00:00
parent 16683aee0e
commit adbc4a7777
3 changed files with 14 additions and 10 deletions

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@@ -12,19 +12,24 @@
*/
import python
private import LegacyPointsTo
private import semmle.python.dataflow.new.internal.DataFlowDispatch
ClassObject left_base(ClassObject type, ClassObject base) {
exists(int i | i > 0 and type.getBaseType(i) = base and result = type.getBaseType(i - 1))
/**
* Gets the `i`th base class of `cls`, if it can be resolved to a user-defined class.
*/
Class getBaseType(Class cls, int i) { cls.getBase(i) = classTracker(result).asExpr() }
Class left_base(Class type, Class base) {
exists(int i | i > 0 and getBaseType(type, i) = base and result = getBaseType(type, i - 1))
}
predicate invalid_mro(ClassObject t, ClassObject left, ClassObject right) {
t.isNewStyle() and
predicate invalid_mro(Class t, Class left, Class right) {
DuckTyping::isNewStyle(t) and
left = left_base(t, right) and
left = right.getAnImproperSuperType()
left = getADirectSuperclass*(right)
}
from ClassObject t, ClassObject left, ClassObject right
from Class t, Class left, Class right
where invalid_mro(t, left, right)
select t,
"Construction of class " + t.getName() +

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@@ -1 +1 @@
| inconsistent_mro.py:9:1:9:14 | class Z | Construction of class Z can fail due to invalid method resolution order(MRO) for bases $@ and $@. | inconsistent_mro.py:3:1:3:16 | class X | X | inconsistent_mro.py:6:1:6:11 | class Y | Y |
| inconsistent_mro.py:9:1:9:14 | Class Z | Construction of class Z can fail due to invalid method resolution order(MRO) for bases $@ and $@. | inconsistent_mro.py:3:1:3:16 | Class X | X | inconsistent_mro.py:6:1:6:11 | Class Y | Y |

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@@ -1,2 +1 @@
| inconsistent_mro.py:9:1:9:14 | class Z | Construction of class Z can fail due to invalid method resolution order(MRO) for bases $@ and $@. | inconsistent_mro.py:3:1:3:16 | class X | X | inconsistent_mro.py:6:1:6:11 | class Y | Y |
| inconsistent_mro.py:16:1:16:19 | class N | Construction of class N can fail due to invalid method resolution order(MRO) for bases $@ and $@. | file://:Compiled Code:0:0:0:0 | builtin-class object | object | inconsistent_mro.py:12:1:12:8 | class O | O |
| inconsistent_mro.py:9:1:9:14 | Class Z | Construction of class Z can fail due to invalid method resolution order(MRO) for bases $@ and $@. | inconsistent_mro.py:3:1:3:16 | Class X | X | inconsistent_mro.py:6:1:6:11 | Class Y | Y |