fixed PY-9405 Method can be static: handle existing decorators

python/psi-api/src/com/jetbrains/python/psi/PyElementGenerator.java

@@ -91,4 +91,7 @@ public abstract class PyElementGenerator {
 
   public abstract PyExpressionStatement createDocstring(String content);
   public abstract PyPassStatement createPassStatement();
+
+  @NotNull
+  public abstract PyDecoratorList createDecoratorList(@NotNull final String... decoratorTexts);
 }

python/src/com/jetbrains/python/inspections/quickfix/PyMakeMethodStaticQuickFix.java

@@ -10,6 +10,9 @@ import com.jetbrains.python.psi.*;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * User: ktisha
  */
@@ -32,18 +35,26 @@ public class PyMakeMethodStaticQuickFix implements LocalQuickFix {
     final PsiElement element = descriptor.getPsiElement();
     final PyFunction problemFunction = PsiTreeUtil.getParentOfType(element, PyFunction.class);
     if (problemFunction == null) return;
-    if (!PyUtil.deleteParameter(problemFunction, 0)) return;
+    PyUtil.deleteParameter(problemFunction, 0);
+
+    final PyDecoratorList problemDecoratorList = problemFunction.getDecoratorList();
+    List<String> decoTexts = new ArrayList<String>();
+    decoTexts.add("@staticmethod");
+    if (problemDecoratorList != null) {
+      final PyDecorator[] decorators = problemDecoratorList.getDecorators();
+      for (PyDecorator deco : decorators) {
+        decoTexts.add(deco.getText());
+      }
+    }
 
     PyElementGenerator generator = PyElementGenerator.getInstance(project);
-    final PyFunction function =
+    final PyDecoratorList decoratorList = generator.createDecoratorList(decoTexts.toArray(new String[decoTexts.size()]));
-      generator.createFromText(LanguageLevel.forElement(problemFunction), PyFunction.class, "@staticmethod\ndef foo():\n\tpass");
-    final PyDecoratorList decoratorList = function.getDecoratorList();
-    assert decoratorList != null;
-    final PyDecorator[] decorators = decoratorList.getDecorators();
-    final PyDecorator decorator = decorators[0];
-    problemFunction.addBefore(decorator, problemFunction.getFirstChild());
-
-
 
+    if (problemDecoratorList != null) {
+      problemDecoratorList.replace(decoratorList);
+    }
+    else {
+      problemFunction.addBefore(decoratorList, problemFunction.getFirstChild());
+    }
   }
 }

python/src/com/jetbrains/python/psi/impl/PyElementGeneratorImpl.java

@@ -324,6 +324,22 @@ public class PyElementGeneratorImpl extends PyElementGenerator {
     return (PyPassStatement)statementList.getStatements()[0];
   }
 
+  @NotNull
+  @Override
+  public PyDecoratorList createDecoratorList(@NotNull final String... decoratorTexts) {
+    assert decoratorTexts.length > 0;
+    StringBuilder functionText = new StringBuilder();
+    for (String decoText : decoratorTexts) {
+      functionText.append(decoText).append("\n");
+    }
+    functionText.append("def foo():\n\tpass");
+    final PyFunction function = createFromText(LanguageLevel.getDefault(), PyFunction.class,
+                                               functionText.toString());
+    final PyDecoratorList decoratorList = function.getDecoratorList();
+    assert decoratorList != null;
+    return decoratorList;
+  }
+
   private PyStatementList createPassStatementList() {
     final PyFunction function = createFromText(LanguageLevel.getDefault(), PyFunction.class, "def foo():\n\tpass");
     return function.getStatementList();

python/testData/quickFixes/PyMakeMethodStaticQuickFixTest/decoWithParams.py

@@ -0,0 +1,10 @@
+__author__ = 'ktisha'
+
+def foo(x):
+  return x
+
+class A():
+
+    @accepts(int, int)
+    def my_<caret>method(self):
+        print "Smth"

python/testData/quickFixes/PyMakeMethodStaticQuickFixTest/decoWithParams_after.py

@@ -0,0 +1,11 @@
+__author__ = 'ktisha'
+
+def foo(x):
+  return x
+
+class A():
+
+    @staticmethod
+    @accepts(int, int)
+    def my_<caret>method():
+        print "Smth"

python/testData/quickFixes/PyMakeMethodStaticQuickFixTest/functionWithDeco.py

@@ -0,0 +1,10 @@
+__author__ = 'ktisha'
+
+def foo(x):
+  return x
+
+class A():
+
+    @my_deco
+    def my_<caret>method(self):
+        print "Smth"

python/testData/quickFixes/PyMakeMethodStaticQuickFixTest/functionWithDeco_after.py

@@ -0,0 +1,11 @@
+__author__ = 'ktisha'
+
+def foo(x):
+  return x
+
+class A():
+
+    @staticmethod
+    @my_deco
+    def my_method():
+        print "Smth"

python/testData/quickFixes/PyMakeMethodStaticQuickFixTest/noSelf.py

@@ -0,0 +1,8 @@
+__author__ = 'ktisha'
+
+class Child(Base):
+    def __init__(self):
+        super(Child, self).__init__()
+
+    def <caret>f():
+        test = 1

python/testData/quickFixes/PyMakeMethodStaticQuickFixTest/noSelf_after.py

@@ -0,0 +1,9 @@
+__author__ = 'ktisha'
+
+class Child(Base):
+    def __init__(self):
+        super(Child, self).__init__()
+
+    @staticmethod
+    def f():
+        test = 1

python/testSrc/com/jetbrains/python/quickFixes/PyMakeMethodStaticQuickFixTest.java

@@ -20,4 +20,16 @@ public class PyMakeMethodStaticQuickFixTest extends PyQuickFixTestCase {
     doInspectionTest(PyMethodMayBeStaticInspection.class, PyBundle.message("QFIX.NAME.make.static"));
   }
 
+  public void testFunctionWithDeco() {
+    doInspectionTest(PyMethodMayBeStaticInspection.class, PyBundle.message("QFIX.NAME.make.static"));
+  }
+
+  public void testDecoWithParams() {
+    doInspectionTest(PyMethodMayBeStaticInspection.class, PyBundle.message("QFIX.NAME.make.static"));
+  }
+
+  public void testNoSelf() {
+    doInspectionTest(PyMethodMayBeStaticInspection.class, PyBundle.message("QFIX.NAME.make.static"));
+  }
+
 }