implemented W0232: Class has no __init__ method

extracted logic for "add element to statement list" into PyUtil
reused in PyMoveAttributeToInitQuickFix and PyClassHasNoInitInspection

reused AddMethodQuickFix in PyClassHasNoInitInspection

python/src/META-INF/python-plugin-common.xml

@@ -317,6 +317,7 @@
     <localInspection language="Python" shortName="PyPackageRequirementsInspection" bundle="com.jetbrains.python.PyBundle" key="INSP.NAME.requirements" groupKey="INSP.GROUP.python" enabledByDefault="true"  level="WARNING" implementationClass="com.jetbrains.python.inspections.PyPackageRequirementsInspection"/>
     <localInspection language="Python" shortName="PyPep8Inspection" displayName="PEP 8 coding style violation" groupKey="INSP.GROUP.python" enabledByDefault="true" level="WEAK WARNING" implementationClass="com.jetbrains.python.inspections.PyPep8Inspection"/>
     <localInspection language="Python" shortName="PyAttributeOutsideInitInspection" displayName="Instance attribute defined outside _init_" groupKey="INSP.GROUP.python" enabledByDefault="true" level="WEAK WARNING" implementationClass="com.jetbrains.python.inspections.PyAttributeOutsideInitInspection"/>
+    <localInspection language="Python" shortName="PyClassHasNoInitInspection" displayName="Class has no __init__ method" groupKey="INSP.GROUP.python" enabledByDefault="true" level="WEAK WARNING" implementationClass="com.jetbrains.python.inspections.PyClassHasNoInitInspection"/>
     <localInspection language="Python" shortName="PyProtectedMemberInspection" displayName="Access to a protected member of a class" groupKey="INSP.GROUP.python" enabledByDefault="true" level="WEAK WARNING" implementationClass="com.jetbrains.python.inspections.PyProtectedMemberInspection"/>
     <localInspection language="Python" shortName="PyDocstringTypesInspection" bundle="com.jetbrains.python.PyBundle" key="INSP.NAME.docstring.types" groupKey="INSP.GROUP.python" enabledByDefault="true"  level="WEAK WARNING" implementationClass="com.jetbrains.python.inspections.PyDocstringTypesInspection"/>
     <localInspection language="Python" shortName="PyShadowingBuiltinsInspection" displayName="Shadowing built-ins" groupKey="INSP.GROUP.python" enabledByDefault="true"  level="WARNING" implementationClass="com.jetbrains.python.inspections.PyShadowingBuiltinsInspection"/>

python/src/com/jetbrains/python/PyBundle.properties

@@ -471,6 +471,11 @@ INSP.NAME.decorator.outside.class=Class specific decorator on method outside cla
 # PyPackageRequirementsInspection
 INSP.NAME.requirements=Package requirements
 
+# PyClassHasNoInitInspection
+INSP.NAME.class.has.no.init=Class has no __init__ method
+INSP.class.has.no.init=Class has no __init__ method
+INSP.parent.$0.has.no.init=Parent {0} has no __init__ method
+
 
 # Refactoring
 # introduce

python/src/com/jetbrains/python/inspections/PyAttributeOutsideInitInspection.java

@@ -51,7 +51,7 @@ public class PyAttributeOutsideInitInspection extends PyInspection {
       if (containingClass == null) return;
 
       Map<String, PyTargetExpression> attributesInInit = new HashMap<String, PyTargetExpression>();
-      final PyFunction initMethod = containingClass.findMethodByName(PyNames.INIT, true);
+      final PyFunction initMethod = containingClass.findMethodByName(PyNames.INIT, false);
       if (initMethod != null)
         PyClassImpl.collectInstanceAttributes(initMethod, attributesInInit);
 

python/src/com/jetbrains/python/inspections/PyClassHasNoInitInspection.java

@@ -0,0 +1,57 @@
+package com.jetbrains.python.inspections;
+
+import com.intellij.codeInspection.LocalInspectionToolSession;
+import com.intellij.codeInspection.ProblemsHolder;
+import com.intellij.psi.PsiElementVisitor;
+import com.jetbrains.python.PyBundle;
+import com.jetbrains.python.PyNames;
+import com.jetbrains.python.inspections.quickfix.AddMethodQuickFix;
+import com.jetbrains.python.psi.PyClass;
+import com.jetbrains.python.psi.PyFunction;
+import com.jetbrains.python.psi.types.PyClassTypeImpl;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * User: ktisha
+ * See pylint W0232
+ */
+public class PyClassHasNoInitInspection extends PyInspection {
+  @Nls
+  @NotNull
+  @Override
+  public String getDisplayName() {
+    return PyBundle.message("INSP.NAME.class.has.no.init");
+  }
+
+  @NotNull
+  @Override
+  public PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder,
+                                        boolean isOnTheFly,
+                                        @NotNull LocalInspectionToolSession session) {
+    return new Visitor(holder, session);
+  }
+
+  private static class Visitor extends PyInspectionVisitor {
+    public Visitor(@Nullable ProblemsHolder holder, @NotNull LocalInspectionToolSession session) {
+      super(holder, session);
+    }
+
+    @Override
+    public void visitPyClass(PyClass node) {
+      final PyFunction init = node.findMethodByName(PyNames.INIT, false);
+      if (init == null) {
+        registerProblem(node.getNameIdentifier(), PyBundle.message("INSP.class.has.no.init"),
+                        new AddMethodQuickFix("__init__", new PyClassTypeImpl(node, false), false));
+      }
+      for (PyClass ancestor : node.iterateAncestorClasses()) {
+        final PyFunction ancestorInit = ancestor.findMethodByName(PyNames.INIT, false);
+        if (ancestorInit == null) {
+          registerProblem(node.getNameIdentifier(), PyBundle.message("INSP.parent.$0.has.no.init", ancestor.getName()),
+                          new AddMethodQuickFix("__init__", new PyClassTypeImpl(ancestor, false), false));
+        }
+      }
+    }
+  }
+}

python/src/com/jetbrains/python/inspections/PyUnresolvedReferencesInspection.java

@@ -684,7 +684,7 @@ public class PyUnresolvedReferencesInspection extends PyInspection {
           return true;
         }
         final String docString = cls.getDocStringValue();
-        if (docString != null && docString.indexOf("@DynamicAttrs") != -1) {
+        if (docString != null && docString.contains("@DynamicAttrs")) {
           return true;
         }
       }
@@ -697,7 +697,7 @@ public class PyUnresolvedReferencesInspection extends PyInspection {
         PyClass cls = ((PyClassType)qtype).getPyClass();
         if (!PyBuiltinCache.getInstance(element).hasInBuiltins(cls)) {
           if (element.getParent() instanceof PyCallExpression) {
-            actions.add(new AddMethodQuickFix(refText, (PyClassType)qtype));
+            actions.add(new AddMethodQuickFix(refText, (PyClassType)qtype, true));
           }
           else if (!(reference instanceof PyOperatorReference)) {
             actions.add(new AddFieldQuickFix(refText, cls, "None"));

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

@@ -29,11 +29,14 @@ import static com.jetbrains.python.psi.PyUtil.sure;
 public class AddMethodQuickFix implements LocalQuickFix {
 
   private PyClassType myQualifierType;
+  private final boolean myReplaceUsage;
   private String myIdentifier;
 
-  public AddMethodQuickFix(String identifier, PyClassType qualifierType) {
+  public AddMethodQuickFix(String identifier, PyClassType qualifierType,
+                           boolean replaceUsage) {
     myIdentifier = identifier;
     myQualifierType = qualifierType;
+    myReplaceUsage = replaceUsage;
   }
 
   @NotNull
@@ -62,10 +65,12 @@ public class AddMethodQuickFix implements LocalQuickFix {
       PyFunctionBuilder builder = new PyFunctionBuilder(item_name);
       PsiElement pe = problem_elt.getParent();
       String deco_name = null; // set to non-null to add a decorator
-      sure(pe instanceof PyCallExpression);
-      PyArgumentList arglist = ((PyCallExpression)pe).getArgumentList();
-      sure(arglist);
-      final PyExpression[] args = arglist.getArguments();
+      PyExpression[] args = new PyExpression[0];
+      if (pe instanceof PyCallExpression) {
+        PyArgumentList arglist = ((PyCallExpression)pe).getArgumentList();
+        sure(arglist);
+        args = arglist.getArguments();
+      }
       boolean made_instance = false;
       if (call_by_class) {
         if (args.length > 0) {
@@ -107,17 +112,10 @@ public class AddMethodQuickFix implements LocalQuickFix {
         PyDecoratorList deco_list = generator.createFromText(LanguageLevel.getDefault(), PyDecoratorList.class, "@" + deco_name + "\ndef foo(): pass", new int[]{0, 0});
         meth.addBefore(deco_list, meth.getFirstChild()); // in the very beginning
       }
-      
-      final PsiElement first_stmt = cls_stmt_list.getFirstChild();
-      if (first_stmt == cls_stmt_list.getLastChild() && first_stmt instanceof PyPassStatement) {
-        // replace the lone 'pass'
-        meth = (PyFunction) first_stmt.replace(meth);
-      }
-      else {
-        // add ourselves to the bottom
-        meth = (PyFunction) cls_stmt_list.add(meth);
-      }
-      showTemplateBuilder(meth);
+
+      meth = (PyFunction)PyUtil.addElementToStatementList(meth, cls_stmt_list);
+      if (myReplaceUsage)
+        showTemplateBuilder(meth);
     }
     catch (IncorrectOperationException ignored) {
       // we failed. tell about this
@@ -138,7 +136,9 @@ public class AddMethodQuickFix implements LocalQuickFix {
       }
     );
 
-    builder.replaceElement(method.getStatementList(), PyNames.PASS);
+    final PyStatementList statementList = method.getStatementList();
+    if (statementList == null) return;
+    builder.replaceElement(statementList, PyNames.PASS);
 
     builder.run();
   }

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

@@ -46,42 +46,21 @@ public class PyMoveAttributeToInitQuickFix implements LocalQuickFix {
   }
 
   private static boolean addDefinition(PsiElement copy, PyClass containingClass) {
-    PyFunction init = containingClass.findMethodByName(PyNames.INIT, true);
+    PyFunction init = containingClass.findMethodByName(PyNames.INIT, false);
 
     if (init == null) {
       final PyStatementList classStatementList = containingClass.getStatementList();
-      final PyStatement[] statements = classStatementList.getStatements();
       init = PyElementGenerator.getInstance(containingClass.getProject()).createFromText(LanguageLevel.forElement(containingClass),
                                                                                          PyFunction.class,
                                                                                          "def __init__(self):\n\t" +
                                                                                          copy.getText());
-      if (statements.length > 0) {
-        final PyStatement statement = statements[0];
-        if (statement instanceof PyExpressionStatement &&
-            ((PyExpressionStatement)statement).getExpression() == containingClass.getDocStringExpression())
-          classStatementList.addAfter(init, statement);
-        else
-          classStatementList.addBefore(init, statement);
-      }
-      else {
-        classStatementList.add(init);
-      }
+      PyUtil.addElementToStatementList(init, classStatementList);
       return true;
     }
+
     final PyStatementList statementList = init.getStatementList();
     if (statementList == null) return false;
-
-    final PyStatement[] statements = statementList.getStatements();
-    if (statements.length == 1) {
-      final PyStatement firstStatement = statements[0];
-      if (firstStatement instanceof PyPassStatement) {
-        firstStatement.replace(copy);
-      }
-      else
-        statementList.addAfter(copy, statements[statements.length - 1]);
-    }
-    else
-      statementList.addAfter(copy, statements[statements.length - 1]);
+    PyUtil.addElementToStatementList(copy, statementList);
     return true;
   }
 

python/src/com/jetbrains/python/psi/PyUtil.java

@@ -1202,5 +1202,30 @@ public class PyUtil {
     return element instanceof PsiWhiteSpace ? null : element;
   }
 
+
+  public static PsiElement addElementToStatementList(@NotNull PsiElement element, @NotNull PyStatementList statementList) {
+    final PsiElement firstChild = statementList.getFirstChild();
+    if (firstChild == statementList.getLastChild() && firstChild instanceof PyPassStatement) {
+      element = firstChild.replace(element);
+    }
+    else {
+      final PyStatement[] statements = statementList.getStatements();
+      String name = element instanceof PsiNamedElement ? ((PsiNamedElement)element).getName() : "";
+      if (PyNames.INIT.equals(name) && statements.length > 0) {
+        final PyDocStringOwner docStringOwner = PsiTreeUtil.getParentOfType(statementList, PyDocStringOwner.class);
+        final PyStatement firstStatement = statements[0];
+        if (docStringOwner != null && firstStatement instanceof PyExpressionStatement &&
+            ((PyExpressionStatement)firstStatement).getExpression() == docStringOwner.getDocStringExpression()) {
+          element = statementList.addAfter(element, firstStatement);
+        }
+        else
+          element = statementList.addBefore(element, firstStatement);
+      }
+      else {
+        element = statementList.add(element);
+      }
+    }
+    return element;
+  }
 }
 

python/testData/inspections/PyClassHasNoInitInspection/class.py

@@ -0,0 +1,4 @@
+__author__ = 'ktisha'
+class <weak_warning descr="Class has no __init__ method">A</weak_warning>:
+    def foo(self):
+        self.b = 1

python/testData/inspections/PyClassHasNoInitInspection/parentClass.py

@@ -0,0 +1,9 @@
+__author__ = 'ktisha'
+class <weak_warning descr="Class has no __init__ method">A</weak_warning>:
+    def foo(self):
+        self.b = 1
+
+class <weak_warning descr="Parent A has no __init__ method">B</weak_warning>(A):
+    def __init__(self):
+        self.b = 2
+

python/testData/inspections/PyClassHasNoInitInspection/trueNegative.py

@@ -0,0 +1,7 @@
+__author__ = 'ktisha'
+class A:
+    def __init__(self):
+        self._a = 1
+
+    def foo(self):
+        self.b = 1

python/testData/quickFixes/AddMethodQuickFixTest/addInit.py

@@ -0,0 +1,4 @@
+__author__ = 'ktisha'
+class <caret>A(object):
+    def foo(self):
+        self.b = 1

python/testData/quickFixes/AddMethodQuickFixTest/addInit_after.py

@@ -0,0 +1,7 @@
+__author__ = 'ktisha'
+class A(object):
+    def __init__(self):
+        pass
+
+    def foo(self):
+        self.b = 1

python/testSrc/com/jetbrains/python/PyQuickFixTest.java

@@ -115,16 +115,6 @@ public class PyQuickFixTest extends PyTestCase {
                      true, true);
   }
 
-  public void testAddMethodFromInstance() {
-    doInspectionTest("AddMethodFromInstance.py", PyUnresolvedReferencesInspection.class, PyBundle.message("QFIX.NAME.add.method.$0.to.class.$1", "y", "A"),
-                     true, true);
-  }
-
-  public void testAddMethodFromMethod() {
-    doInspectionTest("AddMethodFromMethod.py", PyUnresolvedReferencesInspection.class, PyBundle.message("QFIX.NAME.add.method.$0.to.class.$1", "y", "A"),
-                     true, true);
-  }
-
   public void testRemoveTrailingSemicolon() {
     doInspectionTest("RemoveTrailingSemicolon.py", PyTrailingSemicolonInspection.class, PyBundle.message("QFIX.remove.trailing.semicolon"),
                      true, true);

python/testSrc/com/jetbrains/python/inspections/PyClassHasNoInitInspectionTest.java

@@ -0,0 +1,27 @@
+package com.jetbrains.python.inspections;
+
+import com.jetbrains.python.fixtures.PyTestCase;
+
+/**
+ * User: ktisha
+ */
+public class PyClassHasNoInitInspectionTest extends PyTestCase {
+
+  public void testClass() {
+    doTest();
+  }
+
+  public void testTrueNegative() {
+    doTest();
+  }
+
+  public void testParentClass() {
+    doTest();
+  }
+
+  private void doTest() {
+    myFixture.configureByFile("inspections/PyClassHasNoInitInspection/" + getTestName(true) + ".py");
+    myFixture.enableInspections(PyClassHasNoInitInspection.class);
+    myFixture.checkHighlighting(false, false, true);
+  }
+}

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

@@ -0,0 +1,24 @@
+package com.jetbrains.python.quickFixes;
+
+import com.jetbrains.python.PyBundle;
+import com.jetbrains.python.inspections.PyClassHasNoInitInspection;
+import com.jetbrains.python.inspections.PyUnresolvedReferencesInspection;
+
+/**
+ * User: ktisha
+ */
+public class AddMethodQuickFixTest extends PyQuickFixTestCase {
+
+  public void testAddInit() {
+    doInspectionTest(PyClassHasNoInitInspection.class, PyBundle.message("QFIX.NAME.add.method.$0.to.class.$1", "__init__", "A"));
+  }
+
+  public void testAddMethodFromInstance() {
+    doInspectionTest(PyUnresolvedReferencesInspection.class, PyBundle.message("QFIX.NAME.add.method.$0.to.class.$1", "y", "A"));
+  }
+
+  public void testAddMethodFromMethod() {
+    doInspectionTest(PyUnresolvedReferencesInspection.class, PyBundle.message("QFIX.NAME.add.method.$0.to.class.$1", "y", "A"));
+  }
+
+}

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

@@ -1,57 +1,33 @@
 package com.jetbrains.python.quickFixes;
 
-import com.intellij.codeInsight.intention.IntentionAction;
 import com.intellij.testFramework.TestDataPath;
 import com.jetbrains.python.PyBundle;
-import com.jetbrains.python.PythonTestUtil;
-import com.jetbrains.python.fixtures.PyTestCase;
 import com.jetbrains.python.inspections.PyAttributeOutsideInitInspection;
-import org.jetbrains.annotations.NonNls;
 
 /**
  * User: ktisha
  */
 @TestDataPath("$CONTENT_ROOT/../testData/quickFixes/PyMoveAttributeToInitQuickFixTest")
-public class PyMoveAttributeToInitQuickFixTest extends PyTestCase {
+public class PyMoveAttributeToInitQuickFixTest extends PyQuickFixTestCase {
 
   public void testMoveToInit() {
-    doInspectionTest(PyAttributeOutsideInitInspection.class, true);
+    doInspectionTest(PyAttributeOutsideInitInspection.class, PyBundle.message("QFIX.move.attribute"));
   }
 
   public void testCreateInit() {
-    doInspectionTest(PyAttributeOutsideInitInspection.class, true);
+    doInspectionTest(PyAttributeOutsideInitInspection.class, PyBundle.message("QFIX.move.attribute"));
   }
 
   public void testAddPass() {
-    doInspectionTest(PyAttributeOutsideInitInspection.class, true);
+    doInspectionTest(PyAttributeOutsideInitInspection.class, PyBundle.message("QFIX.move.attribute"));
   }
 
   public void testRemovePass() {
-    doInspectionTest(PyAttributeOutsideInitInspection.class, true);
+    doInspectionTest(PyAttributeOutsideInitInspection.class, PyBundle.message("QFIX.move.attribute"));
   }
 
   public void testSkipDocstring() {
-    doInspectionTest(PyAttributeOutsideInitInspection.class, true);
-  }
-
-  @Override
-  @NonNls
-  protected String getTestDataPath() {
-    return PythonTestUtil.getTestDataPath() + "/quickFixes/PyMoveAttributeToInitQuickFixTest";
-  }
-
-  protected void doInspectionTest(final Class inspectionClass,
-                                  boolean applyFix) {
-    final String testFileName = getTestName(true);
-    myFixture.enableInspections(inspectionClass);
-    myFixture.configureByFile(testFileName + ".py");
-    myFixture.checkHighlighting(true, false, false);
-    final IntentionAction intentionAction = myFixture.findSingleIntention(PyBundle.message("QFIX.move.attribute"));
-    assertNotNull(intentionAction);
-    if (applyFix) {
-      myFixture.launchAction(intentionAction);
-      myFixture.checkResultByFile(testFileName + "_after.py", true);
-    }
+    doInspectionTest(PyAttributeOutsideInitInspection.class, PyBundle.message("QFIX.move.attribute"));
   }
 
 }

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

@@ -0,0 +1,28 @@
+package com.jetbrains.python.quickFixes;
+
+import com.intellij.codeInsight.intention.IntentionAction;
+import com.jetbrains.python.PythonTestUtil;
+import com.jetbrains.python.fixtures.PyTestCase;
+import org.jetbrains.annotations.NonNls;
+
+/**
+ * User: ktisha
+ */
+public abstract class PyQuickFixTestCase extends PyTestCase {
+  @Override
+  @NonNls
+  protected String getTestDataPath() {
+    return PythonTestUtil.getTestDataPath() + "/quickFixes/" + getClass().getSimpleName();
+  }
+
+  protected void doInspectionTest(final Class inspectionClass, final String hint) {
+    final String testFileName = getTestName(true);
+    myFixture.enableInspections(inspectionClass);
+    myFixture.configureByFile(testFileName + ".py");
+    myFixture.checkHighlighting(true, false, false);
+    final IntentionAction intentionAction = myFixture.findSingleIntention(hint);
+    assertNotNull(intentionAction);
+    myFixture.launchAction(intentionAction);
+    myFixture.checkResultByFile(testFileName + "_after.py", true);
+  }
+}