From 8a059733eb9d7140f3320cc80395d77aaf81b4e1 Mon Sep 17 00:00:00 2001
From: Ekaterina Tuzova <Ekaterina.Tuzova@jetbrains.com>
Date: Thu, 19 Sep 2013 20:27:18 +0400
Subject: [PATCH] fixed PY-8946 Classmethod docstring creation

---
 .../psi-api/src/com/jetbrains/python/PyNames.java   |  1 +
 .../documentation/PythonDocumentationProvider.java  | 13 +++++++++----
 .../jetbrains/python/editor/PythonEnterHandler.java |  4 ++--
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/python/psi-api/src/com/jetbrains/python/PyNames.java b/python/psi-api/src/com/jetbrains/python/PyNames.java
index 340a57dbda77..ca7bdadd22ff 100644
--- a/python/psi-api/src/com/jetbrains/python/PyNames.java
+++ b/python/psi-api/src/com/jetbrains/python/PyNames.java
@@ -328,6 +328,7 @@ public class PyNames {
 
   // canonical names, not forced by interpreter
   public static final String CANONICAL_SELF = "self";
+  public static final String CANONICAL_CLS = "cls";
   public static final String BASESTRING = "basestring";
 
   /**
diff --git a/python/src/com/jetbrains/python/documentation/PythonDocumentationProvider.java b/python/src/com/jetbrains/python/documentation/PythonDocumentationProvider.java
index f9dfdfd352bf..66f44a2d62a6 100644
--- a/python/src/com/jetbrains/python/documentation/PythonDocumentationProvider.java
+++ b/python/src/com/jetbrains/python/documentation/PythonDocumentationProvider.java
@@ -534,8 +534,11 @@ public class PythonDocumentationProvider extends AbstractDocumentationProvider i
     }
     String docContent = ws + generateDocumentationContentStub(function, ws, true);
     PyExpressionStatement string = elementGenerator.createDocstring("\"\"\"" + docContent + "\"\"\"");
-    if (insertPlace.getStatements().length != 0) {
-      insertPlace.addBefore(string, insertPlace.getStatements()[0]);
+    if (insertPlace != null) {
+      final PyStatement[] statements = insertPlace.getStatements();
+      if (statements.length != 0) {
+        insertPlace.addBefore(string, statements[0]);
+      }
     }
     PyStringLiteralExpression docstring = function.getDocStringExpression();
     if (editor != null && docstring != null) {
@@ -563,12 +566,14 @@ public class PythonDocumentationProvider extends AbstractDocumentationProvider i
     final StringBuilder builder = new StringBuilder(offset);
     final TypeEvalContext context = TypeEvalContext.userInitiated(function.getContainingFile());
     PySignature signature = PySignatureCacheManager.getInstance(function.getProject()).findSignature(function);
-
+    final PyDecoratorList decoratorList = function.getDecoratorList();
+    final PyDecorator classMethod = decoratorList == null ? null : decoratorList.findDecorator(PyNames.CLASSMETHOD);
     for (PyParameter p : PyUtil.getParameters(function, context)) {
       final String parameterName = p.getName();
       if (p.getText().equals(PyNames.CANONICAL_SELF) || parameterName == null) {
         continue;
       }
+      if (classMethod != null && parameterName.equals(PyNames.CANONICAL_CLS)) continue;
       String argType = signature == null ? null : signature.getArgTypeQualifiedName(parameterName);
 
       if (argType == null) {
@@ -583,7 +588,7 @@ public class PythonDocumentationProvider extends AbstractDocumentationProvider i
         builder.append("type ");
         builder.append(parameterName);
         builder.append(": ");
-        if (signature != null) {
+        if (signature != null && argType != null) {
           builder.append(PySignatureUtil.getShortestImportableName(function, argType));
         }
         builder.append(offset);
diff --git a/python/src/com/jetbrains/python/editor/PythonEnterHandler.java b/python/src/com/jetbrains/python/editor/PythonEnterHandler.java
index 967c285fe5db..e32fcb79c340 100644
--- a/python/src/com/jetbrains/python/editor/PythonEnterHandler.java
+++ b/python/src/com/jetbrains/python/editor/PythonEnterHandler.java
@@ -230,13 +230,13 @@ public class PythonEnterHandler extends EnterHandlerDelegateAdapter {
     if (fun != null) {
       String docStub = provider.generateDocumentationContentStub(fun, false);
       docStub += element.getParent().getText().substring(0,3);
-      if (docStub != null && docStub.length() != 0) {
+      if (docStub.length() != 0) {
         editor.getDocument().insertString(editor.getCaretModel().getOffset(), docStub);
         return;
       }
     }
     PyElement klass = PsiTreeUtil.getParentOfType(element, PyClass.class, PyFile.class);
-    if (klass != null) {
+    if (klass != null && element != null) {
       editor.getDocument().insertString(editor.getCaretModel().getOffset(),
                       PythonDocCommentUtil.generateDocForClass(klass, element.getParent().getText().substring(0, 3)));
     }