no import reference completion in incomplete/invalid import statements

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

@@ -13,6 +13,7 @@ import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiDirectory;
 import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiErrorElement;
 import com.intellij.psi.PsiFile;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.PsiTreeUtil;
@@ -79,6 +80,15 @@ public class PyImportReferenceImpl extends PyReferenceImpl {
   @NotNull
   @Override
   public Object[] getVariants() {
+    // no completion in invalid import statements
+    PyImportElement importElement = PsiTreeUtil.getParentOfType(myElement, PyImportElement.class);
+    if (importElement != null) {
+      PsiErrorElement prevError = PsiTreeUtil.getPrevSiblingOfType(importElement, PsiErrorElement.class);
+      if (prevError != null) {
+        return ArrayUtil.EMPTY_OBJECT_ARRAY;
+      }
+    }
+
     PyExpression qualifier = myElement.getQualifier();
     if (qualifier != null) {
       // qualifier's type must be module, it should know how to complete

python/testData/completion/noIdentifiersInImport.after.py

@@ -0,0 +1 @@
+from sys stdo

python/testData/completion/noIdentifiersInImport.py

@@ -0,0 +1 @@
+from sys stdo<caret>

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

@@ -263,4 +263,8 @@ public class PythonCompletionTest extends PyLightFixtureTestCase {
   public void testFromDotImport() {  // PY-2772
     doTest3K();
   }
+
+  public void testNoIdentifiersInImport() {
+    doTest();
+  }
 }