From 27543fe191430ed05646523e2a5f487c57390815 Mon Sep 17 00:00:00 2001
From: Semyon Proshev <Semyon.Proshev@jetbrains.com>
Date: Wed, 28 Sep 2016 19:39:41 +0300
Subject: [PATCH] PY-20946 Fixed: False positive: `__init_subclass__` method
 first parameter should be named "self"

Update PyMethodParametersInspection to correctly handle Python 3.6 __init_subclass__ method. This method is implicitly a @classmethod
---
 python/psi-api/src/com/jetbrains/python/PyNames.java   |  3 ++-
 .../inspections/PyMethodParametersInspection.java      |  4 +++-
 .../PyMethodParametersInspectionInitSubclass/test.py   | 10 ++++++++++
 .../com/jetbrains/python/PythonInspectionsTest.java    |  4 ++++
 4 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 python/testData/inspections/PyMethodParametersInspectionInitSubclass/test.py

diff --git a/python/psi-api/src/com/jetbrains/python/PyNames.java b/python/psi-api/src/com/jetbrains/python/PyNames.java
index f3f787a39390..651e67039aeb 100644
--- a/python/psi-api/src/com/jetbrains/python/PyNames.java
+++ b/python/psi-api/src/com/jetbrains/python/PyNames.java
@@ -170,6 +170,7 @@ public class PyNames {
   public static final String AENTER = "__aenter__";
   public static final String AEXIT = "__aexit__";
   public static final String SIZEOF = "__sizeof__";
+  public static final String INIT_SUBCLASS = "__init_subclass__";
 
   public static final String NAME = "__name__";
   public static final String ENTER = "__enter__";
@@ -434,7 +435,7 @@ public class PyNames {
 
   public static final ImmutableMap<String, BuiltinDescription> PY36_BUILTIN_METHODS = ImmutableMap.<String, BuiltinDescription>builder()
     .putAll(PY35_BUILTIN_METHODS)
-    .put("__init_subclass__", new BuiltinDescription("(cls, **kwargs)"))
+    .put(INIT_SUBCLASS, new BuiltinDescription("(cls, **kwargs)"))
     .put("__set_name__", new BuiltinDescription("(self, owner, name)"))
     .build();
 
diff --git a/python/src/com/jetbrains/python/inspections/PyMethodParametersInspection.java b/python/src/com/jetbrains/python/inspections/PyMethodParametersInspection.java
index 86b763820513..e60ba1dbee4c 100644
--- a/python/src/com/jetbrains/python/inspections/PyMethodParametersInspection.java
+++ b/python/src/com/jetbrains/python/inspections/PyMethodParametersInspection.java
@@ -205,7 +205,9 @@ public class PyMethodParametersInspection extends PyInspection {
                 );
               }
             }
-            else if (flags.isClassMethod() || PyNames.NEW.equals(methodName)) {
+            else if (flags.isClassMethod() ||
+                     PyNames.NEW.equals(methodName) ||
+                     PyNames.INIT_SUBCLASS.equals(methodName) && LanguageLevel.forElement(node).isAtLeast(LanguageLevel.PYTHON36)) {
               if (!CLS.equals(pname)) {
                 registerProblem(
                   PyUtil.sure(params[0].getNode()).getPsi(),
diff --git a/python/testData/inspections/PyMethodParametersInspectionInitSubclass/test.py b/python/testData/inspections/PyMethodParametersInspectionInitSubclass/test.py
new file mode 100644
index 000000000000..794d1177cae6
--- /dev/null
+++ b/python/testData/inspections/PyMethodParametersInspectionInitSubclass/test.py
@@ -0,0 +1,10 @@
+class QuestBase:
+    def __init_subclass__(cls, swallow, **kwargs):
+        cls.swallow = swallow
+        super().__init_subclass__(**kwargs)
+
+
+class QuestBase:
+    def __init_subclass__(<weak_warning descr="Usually first parameter of such methods is named 'cls'">self</weak_warning>, swallow, **kwargs):
+        self.swallow = swallow
+        super().__init_subclass__(**kwargs)
\ No newline at end of file
diff --git a/python/testSrc/com/jetbrains/python/PythonInspectionsTest.java b/python/testSrc/com/jetbrains/python/PythonInspectionsTest.java
index da69bbbdfa4d..76130c106c11 100644
--- a/python/testSrc/com/jetbrains/python/PythonInspectionsTest.java
+++ b/python/testSrc/com/jetbrains/python/PythonInspectionsTest.java
@@ -69,6 +69,10 @@ public class PythonInspectionsTest extends PyTestCase {
     myFixture.checkHighlighting(true, false, true);
   }
 
+  public void testPyMethodParametersInspectionInitSubclass() {
+    doHighlightingTest(PyMethodParametersInspection.class, LanguageLevel.PYTHON36);
+  }
+
   public void testPyNestedDecoratorsInspection() {
     LocalInspectionTool inspection = new PyNestedDecoratorsInspection();
     doTest(getTestName(false), inspection);