Merge pull request github#3460 from yoff/boolDefault

Python: __bool__ does not raise TypeError by default

Author: RasmusWL

python/ql/src/Functions/IncorrectRaiseInSpecialMethod.ql

@@ -82,8 +82,6 @@ private predicate ordering_method(string name) {
 private predicate cast_method(string name) {
     name = "__nonzero__" and major_version() = 2
     or
-    name = "__bool__"
-    or
     name = "__int__"
     or
     name = "__float__"
@@ -118,6 +116,8 @@ predicate preferred_raise(string name, ClassObject ex) {
     ordering_method(name) and ex = theTypeErrorType()
     or
     arithmetic_method(name) and ex = Object::builtin("ArithmeticError")
+    or
+    name = "__bool__" and ex = theTypeErrorType()
 }
 
 predicate no_need_to_raise(string name, string message) {

python/ql/test/query-tests/Functions/general/IncorrectRaiseInSpecialMethod.expected

@@ -1,2 +1,3 @@
 | protocols.py:98:5:98:33 | Function __getitem__ | Function always raises $@; raise LookupError instead | file://:Compiled Code:0:0:0:0 | builtin-class ZeroDivisionError | builtin-class ZeroDivisionError |
 | protocols.py:101:5:101:26 | Function __getattr__ | Function always raises $@; raise AttributeError instead | file://:Compiled Code:0:0:0:0 | builtin-class ZeroDivisionError | builtin-class ZeroDivisionError |
+| protocols.py:104:5:104:23 | Function __bool__ | Function always raises $@; raise TypeError instead | file://:Compiled Code:0:0:0:0 | builtin-class ZeroDivisionError | builtin-class ZeroDivisionError |

python/ql/test/query-tests/Functions/general/SignatureSpecialMethods.expected

@@ -5,5 +5,5 @@
 | om_test.py:71:5:71:19 | Function WrongSpecials.__repr__ | Too few parameters for special method __repr__, which has no parameters, but should have 1, in class $@. | om_test.py:57:1:57:28 | class WrongSpecials | WrongSpecials |
 | om_test.py:74:5:74:46 | Function WrongSpecials.__add__ | 1 default values(s) will never be used for special method __add__, in class $@. | om_test.py:57:1:57:28 | class WrongSpecials | WrongSpecials |
 | om_test.py:97:15:97:34 | Function NotOKSpecials.lambda | Too few parameters for special method __sub__, which has 1 parameter, but should have 2, in class $@. | om_test.py:95:1:95:28 | class NotOKSpecials | NotOKSpecials |
-| protocols.py:104:1:104:12 | Function f | Too few parameters for special method __add__, which has 1 parameter, but should have 2, in class $@. | protocols.py:107:1:107:29 | class MissingMethods | MissingMethods |
-| protocols.py:104:1:104:12 | Function f | Too few parameters for special method __set__, which has 1 parameter, but should have 3, in class $@. | protocols.py:107:1:107:29 | class MissingMethods | MissingMethods |
+| protocols.py:107:1:107:12 | Function f | Too few parameters for special method __add__, which has 1 parameter, but should have 2, in class $@. | protocols.py:110:1:110:29 | class MissingMethods | MissingMethods |
+| protocols.py:107:1:107:12 | Function f | Too few parameters for special method __set__, which has 1 parameter, but should have 3, in class $@. | protocols.py:110:1:110:29 | class MissingMethods | MissingMethods |

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

@@ -101,6 +101,9 @@ def __getitem__(self, index):
     def __getattr__(self):
         raise ZeroDivisionError()
 
+    def __bool__(self):
+        raise ZeroDivisionError()
+
 def f(self):
     pass
 
@@ -116,3 +119,8 @@ class OK(object):
     def __call__(self):
         yield 0
         raise StopIteration
+
+    # __bool__ returns `True` by default, so raising `TypeError` should not give an alert
+    # FP reported in https://github.com/github/codeql/issues/2388
+    def __bool__(self):
+        raise TypeError