Fix bad-super-call for non-direct parents (#6956)

Co-authored-by: Pierre Sassoulas <[email protected]>

doc/data/messages/b/bad-super-call/bad.py

@@ -2,6 +2,11 @@ class Animal:
     pass
 
 
+class Tree:
+    pass
+
+
 class Cat(Animal):
     def __init__(self):
-        super(Animal, self).__init__()  # [bad-super-call]
+        super(Tree, self).__init__()  # [bad-super-call]
+        super(Animal, self).__init__()

doc/data/messages/b/bad-super-call/details.rst

@@ -2,3 +2,6 @@ In Python 2.7, ``super()`` has to be called with its own class and ``self`` as a
 lead to a mix up of parent and child class in the code.
 
 In Python 3 the recommended way is to call ``super()`` without arguments (see also ``super-with-arguments``).
+
+One exception is calling ``super()`` on a non-direct parent class. This can be used to get a method other than the default
+method returned by the ``mro()``.

doc/data/messages/b/bad-super-call/good.py

@@ -2,6 +2,10 @@ class Animal:
     pass
 
 
+class Tree:
+    pass
+
+
 class Cat(Animal):
     def __init__(self):
-        super().__init__()
+        super(Animal, self).__init__()

doc/whatsnew/2/2.14/full.rst

@@ -5,6 +5,10 @@ What's New in Pylint 2.14.3?
 ----------------------------
 Release date: TBA
 
+* Fixed two false positives for ``bad-super-call`` for calls that refer to a non-direct parent.
+
+  Closes #4922, Closes #2903
+
 * Fixed a false positive for ``useless-super-delegation`` for subclasses that specify the number of
   of parameters against a parent that uses a variadic argument.
 

pylint/checkers/newstyle.py

@@ -108,7 +108,9 @@ def visit_functiondef(self, node: nodes.FunctionDef) -> None:
                 except astroid.InferenceError:
                     continue
 
-                if klass is not supcls:
+                # If the supcls is in the ancestors of klass super can be used to skip
+                # a step in the mro() and get a method from a higher parent
+                if klass is not supcls and all(i != supcls for i in klass.ancestors()):
                     name = None
                     # if supcls is not Uninferable, then supcls was inferred
                     # and use its name. Otherwise, try to look

tests/functional/s/super/super_checks.py

@@ -29,7 +29,7 @@ def __init__(self):
 class Py3kWrongSuper(Py3kAaaa):
     """new style"""
     def __init__(self):
-        super(NewAaaa, self).__init__()  # [bad-super-call]
+        super(NewAaaa, self).__init__()
 
 class WrongNameRegression(Py3kAaaa):
     """ test a regression with the message """
@@ -59,7 +59,7 @@ class FalsePositive(Empty):
             """The following super is in another scope than `test`."""
             def __init__(self, arg):
                 super(FalsePositive, self).__init__(arg)
-        super(object, 1).__init__() # [bad-super-call]
+        super(object, 1).__init__()
 
 
 class UnknownBases(Missing):
@@ -123,3 +123,34 @@ class SuperWithSelfClass(object):
     """self.__class__ may lead to recursion loop in derived classes"""
     def __init__(self):
         super(self.__class__, self).__init__() # [bad-super-call]
+
+
+# Reported in https://github.com/PyCQA/pylint/issues/2903
+class Parent:
+    def method(self):
+        print()
+
+
+class Child(Parent):
+    def method(self):
+        print("Child")
+        super().method()
+
+class Niece(Parent):
+    def method(self):
+        print("Niece")
+        super().method()
+
+class GrandChild(Child):
+    def method(self):
+        print("Grandchild")
+        super(GrandChild, self).method()
+        super(Child, self).method()
+        super(Niece, self).method()  # [bad-super-call]
+
+
+# Reported in https://github.com/PyCQA/pylint/issues/4922
+class AlabamaCousin(Child, Niece):
+    def method(self):
+        print("AlabamaCousin")
+        super(Child, self).method()

tests/functional/s/super/super_checks.txt

@@ -1,10 +1,8 @@
 no-member:10:8:10:29:Aaaa.hop:Super of 'Aaaa' has no 'hop' member:INFERENCE
 no-member:19:8:19:32:NewAaaa.hop:Super of 'NewAaaa' has no 'hop' member:INFERENCE
 bad-super-call:22:8:22:25:NewAaaa.__init__:Bad first argument 'Aaaa' given to super():UNDEFINED
-bad-super-call:32:8:32:28:Py3kWrongSuper.__init__:Bad first argument 'NewAaaa' given to super():UNDEFINED
 bad-super-call:37:8:37:28:WrongNameRegression.__init__:Bad first argument 'Missing' given to super():UNDEFINED
 bad-super-call:46:8:46:33:CrashSuper.__init__:Bad first argument 'NewAaaa' given to super():UNDEFINED
-bad-super-call:62:8:62:24:SuperDifferentScope.test:Bad first argument 'object' given to super():UNDEFINED
 bad-super-call:70:8:70:28:UnknownBases.__init__:Bad first argument 'Missing' given to super():UNDEFINED
 not-callable:89:8:89:54:InvalidSuperChecks.__init__:super(InvalidSuperChecks, self).not_a_method is not callable:UNDEFINED
 no-member:90:8:90:55:InvalidSuperChecks.__init__:Super of 'InvalidSuperChecks' has no 'attribute_error' member:INFERENCE
@@ -15,3 +13,4 @@ unexpected-keyword-arg:95:8:95:57:InvalidSuperChecks.__init__:Unexpected keyword
 no-member:98:8:98:55:InvalidSuperChecks.__init__:Super of 'InvalidSuperChecks' has no 'attribute_error' member:INFERENCE
 bad-super-call:120:8:120:31:SuperWithType.__init__:Bad first argument 'type' given to super():UNDEFINED
 bad-super-call:125:8:125:35:SuperWithSelfClass.__init__:Bad first argument 'self.__class__' given to super():UNDEFINED
+bad-super-call:149:8:149:26:GrandChild.method:Bad first argument 'Niece' given to super():UNDEFINED