completion that guesses type name by variable name (PY-1010)

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

@@ -42,6 +42,7 @@
     <typedHandler implementation="com.jetbrains.python.editor.ColonTypedHandler" id="pyColonUnindent"/>
 
     <stubIndex implementation="com.jetbrains.python.psi.stubs.PyClassNameIndex"/>
+    <stubIndex implementation="com.jetbrains.python.psi.stubs.PyClassNameIndexInsensitive"/>
     <stubIndex implementation="com.jetbrains.python.psi.stubs.PyFunctionNameIndex"/>
     <stubIndex implementation="com.jetbrains.python.psi.stubs.PySuperClassIndex"/>
 

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

@@ -8,9 +8,9 @@ import com.intellij.util.ProcessingContext;
 import com.jetbrains.python.psi.*;
 import com.jetbrains.python.psi.patterns.SyntaxMatchers;
 import com.jetbrains.python.psi.resolve.*;
+import com.jetbrains.python.psi.stubs.PyClassNameIndexInsensitive;
 import com.jetbrains.python.psi.stubs.PyFunctionNameIndex;
 import com.jetbrains.python.psi.types.*;
-import com.jetbrains.python.toolbox.Maybe;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
@@ -156,6 +156,21 @@ public class PyQualifiedReferenceImpl extends PyReferenceImpl {
         return qualifierType.getCompletionVariants(myElement, ctx);
       }
     }
+    return getUntypedVariants();
+  }
+
+  private Object[] getUntypedVariants() {
+    final PyExpression qualifierElement = myElement.getQualifier();
+    if (qualifierElement instanceof PyReferenceExpression) {
+      PyReferenceExpression qualifier = (PyReferenceExpression)qualifierElement;
+      if (qualifier.getQualifier() == null) {
+        final String className = qualifier.getText();
+        final Collection<PyClass> classes = PyClassNameIndexInsensitive.find(className, getElement().getProject());
+        if (classes.size() == 1) {
+          return new PyClassType(classes.iterator().next(), false).getCompletionVariants(myElement, new ProcessingContext());
+        }
+      }
+    }
     return ArrayUtil.EMPTY_OBJECT_ARRAY;
   }
 

python/src/com/jetbrains/python/psi/impl/stubs/PyClassElementType.java

@@ -14,6 +14,7 @@ import com.jetbrains.python.psi.PyStubElementType;
 import com.jetbrains.python.psi.impl.PyClassImpl;
 import com.jetbrains.python.psi.impl.PyQualifiedName;
 import com.jetbrains.python.psi.stubs.PyClassNameIndex;
+import com.jetbrains.python.psi.stubs.PyClassNameIndexInsensitive;
 import com.jetbrains.python.psi.stubs.PyClassStub;
 import com.jetbrains.python.psi.stubs.PySuperClassIndex;
 
@@ -74,6 +75,7 @@ public class PyClassElementType extends PyStubElementType<PyClassStub, PyClass>
     final String name = stub.getName();
     if (name != null) {
       sink.occurrence(PyClassNameIndex.KEY, name);
+      sink.occurrence(PyClassNameIndexInsensitive.KEY, name.toLowerCase());
     }
     for(PyQualifiedName s: stub.getSuperClasses()) {
       if (s != null) {

python/src/com/jetbrains/python/psi/stubs/PyClassNameIndexInsensitive.java

@@ -0,0 +1,27 @@
+package com.jetbrains.python.psi.stubs;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.search.ProjectScope;
+import com.intellij.psi.stubs.StringStubIndexExtension;
+import com.intellij.psi.stubs.StubIndex;
+import com.intellij.psi.stubs.StubIndexKey;
+import com.intellij.util.io.KeyDescriptor;
+import com.jetbrains.python.psi.PyClass;
+
+import java.util.Collection;
+
+/**
+ * @author yole
+ */
+public class PyClassNameIndexInsensitive extends StringStubIndexExtension<PyClass> {
+  public static final StubIndexKey<String,PyClass> KEY = StubIndexKey.createIndexKey("Py.class.shortNameInsensitive");
+
+  @Override
+  public StubIndexKey<String, PyClass> getKey() {
+    return KEY;
+  }
+
+  public static Collection<PyClass> find(String name, Project project) {
+    return StubIndex.getInstance().get(KEY, name.toLowerCase(), project, ProjectScope.getProjectScope(project));
+  }
+}

python/testData/completion/classNameFromVarName.after.py

@@ -0,0 +1,5 @@
+class Product:
+    def doStuff(self): pass
+
+def foo(product):
+    product.doStuff()

python/testData/completion/classNameFromVarName.py

@@ -0,0 +1,5 @@
+class Product:
+    def doStuff(self): pass
+
+def foo(product):
+    product.doS<caret>

python/testSrc/com/jetbrains/python/PythonCompletionTest.java

@@ -111,6 +111,10 @@ public class PythonCompletionTest extends PyLightFixtureTestCase {
     doTest();
   }
 
+  public void testClassNameFromVarName() throws Exception {
+    doTest();
+  }
+
   public void testImportModule() throws Exception {
     final String testName = "completion/" + getTestName(true);
     myFixture.configureByFiles(testName + ".py", "completion/someModule.py");