mirror of
https://github.com/github/codeql.git
synced 2025-12-24 20:56:33 +01:00
f07a7bf8cf
Will need subsequent PRs fixing up test failures (due to deprecated methods moving around), but other than that everything should be straight-forward.
37 lines
1.3 KiB
Plaintext
37 lines
1.3 KiB
Plaintext
/**
|
|
* @name Nested loops with same variable reused after inner loop body
|
|
* @description Redefining a variable in an inner loop and then using
|
|
* the variable in an outer loop causes unexpected behavior.
|
|
* @kind problem
|
|
* @tags maintainability
|
|
* correctness
|
|
* @problem.severity error
|
|
* @sub-severity low
|
|
* @precision very-high
|
|
* @id py/nested-loops-with-same-variable-reused
|
|
*/
|
|
|
|
import python
|
|
|
|
predicate loop_variable_ssa(For f, Variable v, SsaVariable s) {
|
|
f.getTarget().getAFlowNode() = s.getDefinition() and v = s.getVariable()
|
|
}
|
|
|
|
predicate variableUsedInNestedLoops(For inner, For outer, Variable v, Name n) {
|
|
/* Ignore cases where there is no use of the variable or the only use is in the inner loop. */
|
|
outer.contains(n) and
|
|
not inner.contains(n) and
|
|
/* Only treat loops in body as inner loops. Loops in the else clause are ignored. */
|
|
outer.getBody().contains(inner) and
|
|
exists(SsaVariable s |
|
|
loop_variable_ssa(inner, v, s.getAnUltimateDefinition()) and
|
|
loop_variable_ssa(outer, v, _) and
|
|
s.getAUse().getNode() = n
|
|
)
|
|
}
|
|
|
|
from For inner, For outer, Variable v, Name n
|
|
where variableUsedInNestedLoops(inner, outer, v, n)
|
|
select inner, "Nested for statement $@ loop variable '" + v.getId() + "' of enclosing $@.", n,
|
|
"uses", outer, "for statement"
|