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Merge pull request #2894 from BekaValentine/python-objectapi-to-valueapi-iscomparisons

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Python: ObjectAPI to ValueAPI: IsComparisons
This commit is contained in:
Calum Grant
2020-03-03 17:25:24 +00:00
committed by GitHub
parent a576f3fa54 9601c41fe5
commit 464a034c7d
1 changed files with 14 additions and 15 deletions
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29
python/ql/src/Expressions/IsComparisons.qll
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@@ -28,14 +28,14 @@ predicate probablySingleton(ClassValue cls) {
predicate invalid_to_use_is_portably(ClassValue c) {
overrides_eq_or_cmp(c) and
/* Exclude type/builtin-function/bool as it is legitimate to compare them using 'is' but they implement __eq__ */
// Exclude type/builtin-function/bool as it is legitimate to compare them using 'is' but they implement __eq__
not c = Value::named("type") and not c = ClassValue::builtinFunction() and not c = Value::named("bool") and
/* OK to compare with 'is' if a singleton */
// OK to compare with 'is' if a singleton
not probablySingleton(c)
}
predicate simple_constant(ControlFlowNode f) {
exists(Object obj | f.refersTo(obj) | obj = theTrueObject() or obj = theFalseObject() or obj = theNoneObject())
exists(Value val | f.pointsTo(val) | val = Value::named("True") or val = Value::named("False") or val = Value::named("None"))
}
private predicate cpython_interned_value(Expr e) {
@@ -66,14 +66,14 @@ private predicate universally_interned_value(Expr e) {
predicate cpython_interned_constant(Expr e) {
exists(Expr const |
e.refersTo(_, const) |
e.pointsTo(_, const) |
cpython_interned_value(const)
)
}
predicate universally_interned_constant(Expr e) {
exists(Expr const |
e.refersTo(_, const) |
e.pointsTo(_, const) |
universally_interned_value(const)
)
}
@@ -95,7 +95,7 @@ private predicate comparison_one_type(Compare comp, Cmpop op, ClassValue cls) {
}
predicate invalid_portable_is_comparison(Compare comp, Cmpop op, ClassValue cls) {
/* OK to use 'is' when defining '__eq__' */
// OK to use 'is' when defining '__eq__'
not exists(Function eq | eq.getName() = "__eq__" or eq.getName() = "__ne__" | eq = comp.getScope().getScope*())
and
(
@@ -107,24 +107,24 @@ predicate invalid_portable_is_comparison(Compare comp, Cmpop op, ClassValue cls)
)
)
and
/* OK to use 'is' when comparing items from a known set of objects */
not exists(Expr left, Expr right, Object obj |
// OK to use 'is' when comparing items from a known set of objects
not exists(Expr left, Expr right, Value val |
comp.compares(left, op, right) and
exists(ImmutableLiteral il | il.getLiteralObject() = obj) |
left.refersTo(obj) and right.refersTo(obj)
exists(ImmutableLiteral il | il.getLiteralValue() = val) |
left.pointsTo(val) and right.pointsTo(val)
or
/* Simple constant in module, probably some sort of sentinel */
// Simple constant in module, probably some sort of sentinel
exists(AstNode origin |
not left.refersTo(_) and right.refersTo(obj, origin) and
not left.pointsTo(_) and right.pointsTo(val, origin) and
origin.getScope().getEnclosingModule() = comp.getScope().getEnclosingModule()
)
)
and
/* OK to use 'is' when comparing with a member of an enum */
// OK to use 'is' when comparing with a member of an enum
not exists(Expr left, Expr right, AstNode origin |
comp.compares(left, op, right) and
enum_member(origin) |
left.refersTo(_, origin) or right.refersTo(_, origin)
left.pointsTo(_, origin) or right.pointsTo(_, origin)
)
}
@@ -135,4 +135,3 @@ private predicate enum_member(AstNode obj) {
asgn.getValue() = obj
)
}