PY-15656 Insert closing parenthesis of parameter list right after opening one if there are no parameters

python/src/com/jetbrains/python/codeInsight/editorActions/smartEnter/fixers/PyParameterListFixer.java

@@ -40,19 +40,22 @@ public class PyParameterListFixer extends PyFixer<PyParameterList> {
   }
 
   @Override
-  public void doApply(@NotNull Editor editor, @NotNull PySmartEnterProcessor processor, @NotNull PyParameterList psiElement)
+  public void doApply(@NotNull Editor editor, @NotNull PySmartEnterProcessor processor, @NotNull PyParameterList parameters)
     throws IncorrectOperationException {
-    final PsiElement lBrace = PyUtil.getChildByFilter(psiElement, PyTokenTypes.OPEN_BRACES, 0);
-    final PsiElement rBrace = PyUtil.getChildByFilter(psiElement, PyTokenTypes.CLOSE_BRACES, 0);
-    final PyFunction pyFunction = as(psiElement.getParent(), PyFunction.class);
+    final PsiElement lBrace = PyUtil.getChildByFilter(parameters, PyTokenTypes.OPEN_BRACES, 0);
+    final PsiElement rBrace = PyUtil.getChildByFilter(parameters, PyTokenTypes.CLOSE_BRACES, 0);
+    final PyFunction pyFunction = as(parameters.getParent(), PyFunction.class);
     if (pyFunction != null && !PyFunctionFixer.isFakeFunction(pyFunction) && (lBrace == null || rBrace == null)) {
       final Document document = editor.getDocument();
       if (lBrace == null) {
         final String textToInsert = pyFunction.getNameNode() == null ? " (" : "(";
-        document.insertString(psiElement.getTextOffset(), textToInsert);
+        document.insertString(parameters.getTextOffset(), textToInsert);
+      }
+      else if (parameters.getParameters().length == 0) {
+        document.insertString(lBrace.getTextRange().getEndOffset(), ")");
       }
       else {
-        document.insertString(psiElement.getTextRange().getEndOffset(), ")");
+        document.insertString(parameters.getTextRange().getEndOffset(), ")");
       }
     }
   }

python/testData/codeInsight/smartEnter/unclosedParametersListAndTrailingEmptyLines.py

@@ -0,0 +1,2 @@
+def fun<caret>c(
+

python/testData/codeInsight/smartEnter/unclosedParametersListAndTrailingEmptyLines_after.py

@@ -0,0 +1,3 @@
+def func():
+    <caret>
+

python/testSrc/com/jetbrains/python/PySmartEnterTest.java

@@ -185,6 +185,12 @@ public class PySmartEnterTest extends PyTestCase {
     doTest();
   }
 
+
+  // PY-15656
+  public void testUnclosedParametersListAndTrailingEmptyLines() {
+    doTest();
+  }
+
   // PY-12877
   public void testWithTargetOmitted() {
     doTest();