Add new old-style-super check to flag instances of super with default arguments

7 files changed, 80 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 2e47d45fe..4fa958010 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -16,6 +16,8 @@ Release date: TBA
 
 * mixed-indentation has been removed, it is no longer useful since TabError is included directly in python3
 
+* Add `old-style-super` check for flagging instances of Python 2 style super calls.
+
    Close #2984 #3573
 
 What's New in Pylint 2.5.1?
diff --git a/doc/whatsnew/2.6.rst b/doc/whatsnew/2.6.rst
index 92a72e3c0..c00053acd 100644
--- a/doc/whatsnew/2.6.rst
+++ b/doc/whatsnew/2.6.rst
@@ -13,6 +13,8 @@ Summary -- Release highlights
 New checkers
 ============
 
+* Add `old-style-super` check for flagging instances of Python 2 style super calls.
+
 Other Changes
 =============
 
diff --git a/pylint/checkers/python3.py b/pylint/checkers/python3.py
index 11fc0eec0..0f5690020 100644
--- a/pylint/checkers/python3.py
+++ b/pylint/checkers/python3.py
@@ -598,6 +598,12 @@ class Python3Checker(checkers.BaseChecker):
             "variables will be deleted outside of the "
             "comprehension.",
         ),
+        "C1601": (
+            "Consider using Python 3 style super() without arguments",
+            "old-style-super",
+            "Emitted when calling the super builtin with the current class "
+            "and instance. On Python 3 these arguments are the default.",
+        ),
     }
 
     _bad_builtins = frozenset(
@@ -1233,12 +1239,26 @@ class Python3Checker(checkers.BaseChecker):
                     if not _in_iterating_context(node):
                         checker = "{}-builtin-not-iterating".format(node.func.name)
                         self.add_message(checker, node=node)
-                if node.func.name == "open" and node.keywords:
+                elif node.func.name == "open" and node.keywords:
                     kwargs = node.keywords
                     for kwarg in kwargs or []:
                         if kwarg.arg == "encoding":
                             self._validate_encoding(kwarg.value, node)
                             break
+                elif node.func.name == "super":
+                    if len(node.args) != 2:
+                        return
+                    if (
+                        not isinstance(node.args[1], astroid.Name)
+                        or node.args[1].name != "self"
+                    ):
+                        return
+                    if (
+                        not isinstance(node.args[1], astroid.Name)
+                        or node.args[0].name != node.scope().parent.name
+                    ):
+                        return
+                    self.add_message("old-style-super", node=node)
 
     def _validate_encoding(self, encoding, node):
         if isinstance(encoding, astroid.Const):
diff --git a/tests/checkers/unittest_python3.py b/tests/checkers/unittest_python3.py
index fdb5b26fd..e6c5b5fe1 100644
--- a/tests/checkers/unittest_python3.py
+++ b/tests/checkers/unittest_python3.py
@@ -1153,3 +1153,37 @@ class TestPython3Checker(testutils.CheckerTestCase):
         message = testutils.Message("next-method-defined", node=node)
         with self.assertAddsMessages(message):
             self.checker.visit_functiondef(node)
+
+    def test_old_style_super(self):
+        node = astroid.extract_node(
+            """
+            class Foo(object):
+                def __init__():
+                    super(Foo, self).__init__()  #@
+            """
+        ).func.expr
+        message = testutils.Message("old-style-super", node=node)
+        with self.assertAddsMessages(message):
+            self.checker.visit_call(node)
+
+    def test_super_non_default_args(self):
+        node = astroid.extract_node(
+            """
+            class Foo(object):
+                def __init__():
+                    super(Bar, self).__init__()  #@
+            """
+        ).func.expr
+        with self.assertNoMessages():
+            self.checker.visit_call(node)
+
+    def test_new_style_super(self):
+        node = astroid.extract_node(
+            """
+            class Foo(object):
+                def __init__():
+                    super().__init__()  #@
+            """
+        ).func.expr
+        with self.assertNoMessages():
+            self.checker.visit_call(node)
diff --git a/tests/functional/s/super_style.py b/tests/functional/s/super_style.py
new file mode 100644
index 000000000..342e67c4b
--- /dev/null
+++ b/tests/functional/s/super_style.py
@@ -0,0 +1,17 @@
+class Foo:
+    pass
+
+
+class Bar(Foo):
+    def __init__(self):
+        super(Bar, self).__init__()  # [old-style-super]
+
+
+class Baz(Foo):
+    def __init__(self):
+        super().__init__()
+
+
+class Qux(Foo):
+    def __init__(self):
+        super(Bar, self).__init__()
diff --git a/tests/functional/s/super_style.rc b/tests/functional/s/super_style.rc
new file mode 100644
index 000000000..cfff8dab7
--- /dev/null
+++ b/tests/functional/s/super_style.rc
@@ -0,0 +1,3 @@
+[Messages Control]
+disable=all
+enable=old-style-super
diff --git a/tests/functional/s/super_style.txt b/tests/functional/s/super_style.txt
new file mode 100644
index 000000000..50235699e
--- /dev/null
+++ b/tests/functional/s/super_style.txt
@@ -0,0 +1 @@
+old-style-super:7:Bar.__init__:Consider using Python 3 style super() without arguments