Java: Don't fold parameters of extracted method when there are duplicates that might use unfolded parameters (IDEA-189023)

java/java-impl/src/com/intellij/refactoring/extractMethod/JavaDuplicatesExtractMethodProcessor.java

@@ -53,16 +53,16 @@ public class JavaDuplicatesExtractMethodProcessor extends ExtractMethodProcessor
     myArtificialOutputVariable = variablesMapping.getOrDefault(from.myArtificialOutputVariable, from.myArtificialOutputVariable);
 
     List<VariableData> variableDatum = new ArrayList<>();
+    List<VariableData> inputVariables = getInputVariables().getInputVariables();
     for (int i = 0; i < from.myVariableDatum.length; i++) {
       VariableData fromData = from.myVariableDatum[i];
       PsiVariable mappedVariable = variablesMapping.get(fromData.variable);
-      if (isReferenced(mappedVariable, fromData.variable)) {
+      if (isReferenced(mappedVariable, fromData.variable) && isUnchanged(mappedVariable, fromData.type, inputVariables)) {
         VariableData newData = fromData.substitute(mappedVariable);
         variableDatum.add(newData);
       }
     }
     Set<PsiVariable> parameterVariables = ContainerUtil.map2Set(variableDatum, data -> data.variable);
-    List<VariableData> inputVariables = getInputVariables().getInputVariables();
     for (VariableData data : inputVariables) {
       if (!parameterVariables.contains(data.variable)) {
         variableDatum.add(data);
@@ -71,6 +71,15 @@ public class JavaDuplicatesExtractMethodProcessor extends ExtractMethodProcessor
     myVariableDatum = variableDatum.toArray(new VariableData[0]);
   }
 
+  private static boolean isUnchanged(PsiVariable fromVariable, PsiType fromType, @NotNull List<VariableData> inputVariables) {
+    for (VariableData data : inputVariables) {
+      if (data.variable == fromVariable) {
+        return data.type != null && data.type.equalsToText(fromType.getCanonicalText());
+      }
+    }
+    return true;
+  }
+
   public void applyFromSnapshot(@NotNull ExtractMethodSnapshot from) {
     myMethodName = from.myMethodName;
     myStatic = from.myStatic;

java/java-tests/testData/refactoring/extractMethod/ParametrizedDuplicateUnfoldArrayArgument.java

@@ -0,0 +1,17 @@
+class DeclaredOutputVariable {
+    void foo(String[] a) {
+        <selection>
+        String s = a[1];
+        if (s == null) return;
+        System.out.println(s.charAt(1));
+        </selection>
+        System.out.println(s.length());
+    }
+
+    void bar(String[] a) {
+        String s = a[2];
+        if (s == null) return;
+        System.out.println(s.charAt(2));
+        System.out.println(s.length());
+    }
+}

java/java-tests/testData/refactoring/extractMethod/ParametrizedDuplicateUnfoldArrayArgument_after.java

@@ -0,0 +1,25 @@
+import org.jetbrains.annotations.Nullable;
+
+class DeclaredOutputVariable {
+    void foo(String[] a) {
+
+        String s = newMethod(a, 1);
+        if (s == null) return;
+
+        System.out.println(s.length());
+    }
+
+    @Nullable
+    private String newMethod(String[] a, int i) {
+        String s = a[i];
+        if (s == null) return null;
+        System.out.println(s.charAt(i));
+        return s;
+    }
+
+    void bar(String[] a) {
+        String s = newMethod(a, 2);
+        if (s == null) return;
+        System.out.println(s.length());
+    }
+}

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

@@ -889,6 +889,10 @@ public class ExtractMethodTest extends LightCodeInsightTestCase {
     doDuplicatesTest();
   }
 
+  public void testParametrizedDuplicateUnfoldArrayArgument() throws Exception {
+    doDuplicatesTest();
+  }
+
   public void testSuggestChangeSignatureWithChangedParameterName() throws Exception {
     configureByFile(BASE_PATH + getTestName(false) + ".java");
     boolean success = performExtractMethod(true, true, getEditor(), getFile(), getProject(), false, null, false, "p");