do not skip control flow for unreachable code (IDEA-87654)

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

@@ -46,7 +46,7 @@ public class ControlFlowWrapper {
   public ControlFlowWrapper(Project project, PsiElement codeFragment, PsiElement[] elements) throws PrepareFailedException {
     try {
       myControlFlow =
-        ControlFlowFactory.getInstance(project).getControlFlow(codeFragment, new LocalsControlFlowPolicy(codeFragment), false, true);
+        ControlFlowFactory.getInstance(project).getControlFlow(codeFragment, new LocalsControlFlowPolicy(codeFragment), false, false);
     }
     catch (AnalysisCanceledException e) {
       throw new PrepareFailedException(RefactoringBundle.message("extract.method.control.flow.analysis.failed"), e.getErrorElement());
@@ -232,7 +232,7 @@ public class ControlFlowWrapper {
     return true;
   }
 
-  public List<PsiVariable> getInputVariables(final PsiElement codeFragment) {
+  public List<PsiVariable> getInputVariables(final PsiElement codeFragment, PsiElement[] elements) {
     final List<PsiVariable> inputVariables = ControlFlowUtil.getInputVariables(myControlFlow, myFlowStart, myFlowEnd);
     List<PsiVariable> myInputVariables;
     if (myGenerateConditionalExit) {
@@ -241,7 +241,17 @@ public class ControlFlowWrapper {
       myInputVariables = inputVariableList;
     }
     else {
-      myInputVariables = inputVariables;
+      List<PsiVariable> inputVariableList = new ArrayList<PsiVariable>(inputVariables);
+      for (Iterator<PsiVariable> iterator = inputVariableList.iterator(); iterator.hasNext(); ) {
+        PsiVariable variable = iterator.next();
+        for (PsiElement element : elements) {
+          if (PsiTreeUtil.isAncestor(element, variable, false)) {
+            iterator.remove();
+            break;
+          }
+        }
+      }
+      myInputVariables = inputVariableList;
     }
     //varargs variables go last, otherwise order is induced by original ordering
     Collections.sort(myInputVariables, new Comparator<PsiVariable>() {

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

@@ -1073,7 +1073,7 @@ public class ExtractMethodProcessor implements MatchProvider {
   }
 
   private boolean chooseTargetClass(PsiElement codeFragment, final Pass<ExtractMethodProcessor> extractPass) throws PrepareFailedException {
-    final List<PsiVariable> inputVariables = myControlFlowWrapper.getInputVariables(codeFragment);
+    final List<PsiVariable> inputVariables = myControlFlowWrapper.getInputVariables(codeFragment, myElements);
 
     myNeedChangeContext = false;
     myTargetClass = myCodeFragmentMember instanceof PsiMember

java/java-tests/testData/refactoring/extractMethod/ConstantConditionsAffectingControlFlow1.java

@@ -0,0 +1,13 @@
+class Test {
+
+    public void test(boolean b) {
+        int a = 1;
+        if (true) {
+            System.out.println(a);
+        } else {
+            <selection>System.out.println(a);</selection>
+        }
+    }
+
+
+}

java/java-tests/testData/refactoring/extractMethod/ConstantConditionsAffectingControlFlow1_after.java

@@ -0,0 +1,17 @@
+class Test {
+
+    public void test(boolean b) {
+        int a = 1;
+        if (true) {
+            newMethod(a);
+        } else {
+            newMethod(a);
+        }
+    }
+
+    private void newMethod(int a) {
+        System.out.println(a);
+    }
+
+
+}

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

@@ -1,6 +1,7 @@
 class Test {
   void foo() {
       final String str = newMethod();
+      if (str == null) return;
     new Runnable() {
       public void run() {
         System.out.println(str);
@@ -11,7 +12,7 @@ class Test {
     private String newMethod() {
         final String str = "";
         if (str == "") {
-          return;
+            return null;
         }
         return str;
     }

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

@@ -393,6 +393,10 @@ public class ExtractMethodTest extends LightCodeInsightTestCase {
   public void testConstantConditionsAffectingControlFlow() throws Exception {
     doTest();
   }
+
+  public void testConstantConditionsAffectingControlFlow1() throws Exception {
+    doTest();
+  }
   public void testNotInitializedInsideFinally() throws Exception {
     doTest();
   }