PY-25605 EA-85878 Fix NPE: handle incomplete expressions in PyDemorganIntention

python/src/com/jetbrains/python/codeInsight/intentions/PyDemorganIntention.java

@@ -66,6 +66,7 @@ public class PyDemorganIntention extends PyBaseIntentionAction {
                                                                       PyBinaryExpression.class);
     assert expression != null;
     final PyElementType op = expression.getOperator();
+    assert op != null;
     final String converted = convertConjunctionExpression(expression, op);
     replaceExpression(converted, expression);
   }
@@ -85,7 +86,8 @@ public class PyDemorganIntention extends PyBaseIntentionAction {
     // TODO codeStyleManager.reformat(insertedElement)
   }
 
-  private static String convertConjunctionExpression(PyBinaryExpression exp, PyElementType tokenType) {
+  @NotNull
+  private static String convertConjunctionExpression(@NotNull PyBinaryExpression exp, @NotNull PyElementType tokenType) {
     final PyExpression lhs = exp.getLeftExpression();
     final String lhsText;
     final String rhsText;
@@ -108,8 +110,12 @@ public class PyDemorganIntention extends PyBaseIntentionAction {
     return lhsText + flippedConjunction + rhsText;
   }
 
-  private static String convertLeafExpression(PyExpression condition) {
-    if (isNegation(condition)) {
+  @NotNull
+  private static String convertLeafExpression(@Nullable PyExpression condition) {
+    if (condition == null) {
+      return "";
+    }
+    else if (isNegation(condition)) {
       final PyExpression negated = getNegated(condition);
       if (negated == null) {
         return "";
@@ -125,11 +131,11 @@ public class PyDemorganIntention extends PyBaseIntentionAction {
   }
 
   @Nullable
-  private static PyExpression getNegated(PyExpression expression) {
+  private static PyExpression getNegated(@NotNull PyExpression expression) {
     return ((PyPrefixExpression)expression).getOperand();  // TODO strip ()
   }
 
-  private static boolean isConjunctionExpression(PyExpression expression, PyElementType tokenType) {
+  private static boolean isConjunctionExpression(@Nullable PyExpression expression, @NotNull PyElementType tokenType) {
     if (expression instanceof PyBinaryExpression) {
       final PyElementType operator = ((PyBinaryExpression)expression).getOperator();
       return operator == tokenType;
@@ -137,7 +143,7 @@ public class PyDemorganIntention extends PyBaseIntentionAction {
     return false;
   }
 
-  private static boolean isNegation(PsiElement expression) {
+  private static boolean isNegation(@Nullable PsiElement expression) {
     if (!(expression instanceof PyPrefixExpression)) {
       return false;
     }

python/testData/intentions/PythonDemorganLawIntentionTest/missingOperand.py

@@ -0,0 +1,2 @@
+if a and b <caret>and :
+    pass

python/testData/intentions/PythonDemorganLawIntentionTest/missingOperand_after.py

@@ -0,0 +1,2 @@
+if not (not a or not b or):
+    pass

python/testSrc/com/jetbrains/python/intentions/PythonDemorganLawIntentionTest.java

@@ -20,18 +20,27 @@ import com.jetbrains.python.PyBundle;
 
 public class PythonDemorganLawIntentionTest extends PyIntentionTestCase {
   public void testOr() {
-    doIntentionTest(PyBundle.message("INTN.demorgan.law"));
+    doTest();
   }
 
   public void testNotOr() {
-    doIntentionTest(PyBundle.message("INTN.demorgan.law"));
+    doTest();
   }
 
   public void testOrNot() {
-    doIntentionTest(PyBundle.message("INTN.demorgan.law"));
+    doTest();
   }
 
   public void testComplex() {
+    doTest();
+  }
+
+  // PY-25605
+  public void testMissingOperand() {
+    doTest();
+  }
+
+  private void doTest() {
     doIntentionTest(PyBundle.message("INTN.demorgan.law"));
   }
 }