IDEA-117332 Change signature refactoring should warn about @Contract conflict

java/java-impl/src/com/intellij/refactoring/changeSignature/JavaChangeSignatureUsageProcessor.java

@@ -17,6 +17,7 @@ package com.intellij.refactoring.changeSignature;
 
 import com.intellij.codeInsight.ExceptionUtil;
 import com.intellij.codeInsight.daemon.impl.analysis.JavaHighlightUtil;
+import com.intellij.codeInspection.dataFlow.ControlFlowAnalyzer;
 import com.intellij.lang.StdLanguages;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.diagnostic.Logger;
@@ -884,7 +885,7 @@ public class JavaChangeSignatureUsageProcessor implements ChangeSignatureUsagePr
   private static class ConflictSearcher {
     private final JavaChangeInfo myChangeInfo;
 
-    private ConflictSearcher(JavaChangeInfo changeInfo) {
+    private ConflictSearcher(@NotNull JavaChangeInfo changeInfo) {
       this.myChangeInfo = changeInfo;
     }
 
@@ -901,6 +902,8 @@ public class JavaChangeSignatureUsageProcessor implements ChangeSignatureUsagePr
           LOG.error(e);
         }
       }
+      
+      checkContract(conflictDescriptions, myChangeInfo.getMethod());
 
       for (UsageInfo usageInfo : usagesSet) {
         final PsiElement element = usageInfo.getElement();
@@ -914,6 +917,8 @@ public class JavaChangeSignatureUsageProcessor implements ChangeSignatureUsagePr
               conflictDescriptions.putValue(baseMethod, "Implicit last parameter should not be deleted");
             }
           }
+
+          checkContract(conflictDescriptions, method);
         } else if (element instanceof PsiMethodReferenceExpression) {
           conflictDescriptions.putValue(element, "Changed method is used in method reference");
         }
@@ -922,6 +927,12 @@ public class JavaChangeSignatureUsageProcessor implements ChangeSignatureUsagePr
       return conflictDescriptions;
     }
 
+    private static void checkContract(MultiMap<PsiElement, String> conflictDescriptions, PsiMethod method) {
+      if (ControlFlowAnalyzer.findContractAnnotation(method) != null) {
+        conflictDescriptions.putValue(method, "@Contract annotation will have to be changed manually");
+      }
+    }
+
     private boolean needToChangeCalls() {
       return myChangeInfo.isNameChanged() || myChangeInfo.isParameterSetOrOrderChanged() || myChangeInfo.isExceptionSetOrOrderChanged();
     }
@@ -964,9 +975,6 @@ public class JavaChangeSignatureUsageProcessor implements ChangeSignatureUsagePr
 
     private void addMethodConflicts(MultiMap<PsiElement, String> conflicts) {
       String newMethodName = myChangeInfo.getNewName();
-      if (!(myChangeInfo instanceof JavaChangeInfo)) {
-        return;
-      }
       try {
         PsiMethod prototype;
         final PsiMethod method = myChangeInfo.getMethod();

java/java-tests/testData/refactoring/changeSignature/WarnAboutContract.java

@@ -0,0 +1,6 @@
+class A {
+  @org.jetbrains.annotations.Contract("null,_->fail")  
+  public int method<caret>(Object i, Object j) {
+        return 0;
+    }
+}

java/java-tests/testSrc/com/intellij/refactoring/ChangeSignatureTest.java

@@ -42,6 +42,15 @@ public class ChangeSignatureTest extends LightRefactoringTestCase {
     doTest(null, new ParameterInfoImpl[]{new ParameterInfoImpl(1), new ParameterInfoImpl(0)}, false);
   }
 
+  public void testWarnAboutContract() throws Exception {
+    try {
+      doTest(null, new ParameterInfoImpl[]{new ParameterInfoImpl(1), new ParameterInfoImpl(0)}, false);
+      fail("Conflict expected");
+    }
+    catch (BaseRefactoringProcessor.ConflictsInTestsException ignored) {
+    }
+  }
+
   public void testGenericTypes() throws Exception {
     doTest(null, null, "T", new GenParams() {
       @Override