Merge pull request github#3410 from RasmusWL/python-fix-3397

Python: More safe methods for py/modification-of-default-value

Author: tausbn

python/ql/src/Functions/ModificationOfParameterWithDefault.ql

@@ -25,7 +25,10 @@ predicate safe_method(string name) {
     name = "values" or
     name = "iteritems" or
     name = "iterkeys" or
-    name = "itervalues"
+    name = "itervalues" or
+    name = "__contains__" or
+    name = "__getitem__" or
+    name = "__getattribute__"
 }
 
 /** Gets the truthiness (non emptyness) of the default of `p` if that value is mutable */

python/ql/test/query-tests/Functions/general/functions_test.py

@@ -193,3 +193,8 @@ def list_default(x=[1,2,3,4]):
 
 def tuple_default(x=(1,2)):
     do_stuff_based_on_type(x)
+
+# Modification of parameter with default (safe method)
+
+def safe_method(x=[]):
+    return x.count(42)