IDEA-52624 Returns from endless loops are not considered 'all execution paths' returning a value

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/controlFlow/impl/ControlFlowBuilder.java

@@ -15,8 +15,10 @@
  */
 package org.jetbrains.plugins.groovy.lang.psi.controlFlow.impl;
 
+import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Pair;
 import com.intellij.psi.JavaPsiFacade;
+import com.intellij.psi.PsiConstantEvaluationHelper;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiType;
 import com.intellij.psi.tree.IElementType;
@@ -51,6 +53,12 @@ public class ControlFlowBuilder extends GroovyRecursiveElementVisitor {
   private List<InstructionImpl> myInstructions;
 
   private Stack<InstructionImpl> myProcessingStack;
+  private PsiConstantEvaluationHelper myConstantEvaluator;
+
+  public ControlFlowBuilder(Project project) {
+    myConstantEvaluator = JavaPsiFacade.getInstance(project).getConstantEvaluationHelper();
+
+  }
 
   private class ExceptionInfo {
     GrCatchClause myClause;
@@ -485,7 +493,10 @@ public class ControlFlowBuilder extends GroovyRecursiveElementVisitor {
     if (condition != null) {
       condition.accept(this);
     }
-    addPendingEdge(whileStatement, myHead); //break
+    final boolean endless = Boolean.TRUE.equals(myConstantEvaluator.computeConstantExpression(condition));
+    if (!endless) {
+      addPendingEdge(whileStatement, myHead); //break
+    }
     final GrCondition body = whileStatement.getBody();
     if (body != null) {
       body.accept(this);

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/GroovyFileBaseImpl.java

@@ -177,7 +177,7 @@ public abstract class GroovyFileBaseImpl extends PsiFileBase implements GroovyFi
 
   public Instruction[] getControlFlow() {
     if (myControlFlow == null) {
-      myControlFlow = new ControlFlowBuilder().buildControlFlow(this, null, null);
+      myControlFlow = new ControlFlowBuilder(getProject()).buildControlFlow(this, null, null);
     }
 
     return myControlFlow;

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/blocks/GrBlockImpl.java

@@ -49,7 +49,7 @@ public abstract class GrBlockImpl extends GroovyPsiElementImpl implements GrCode
 
   public Instruction[] getControlFlow() {
     if (myControlFlow == null) {
-      myControlFlow = new ControlFlowBuilder().buildControlFlow(this, null, null);
+      myControlFlow = new ControlFlowBuilder(getProject()).buildControlFlow(this, null, null);
     }
 
     return myControlFlow;

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/MissingReturnTest.java

@@ -33,6 +33,7 @@ public class MissingReturnTest extends LightCodeInsightFixtureTestCase {
   public void testMissingReturnOvertReturnType() throws Throwable {doTest();}
   public void testMissingReturnFromClosure() throws Throwable {doTest();}
   public void testReturnsWithoutValue() throws Throwable {doTest();}
+  public void testEndlessLoop() throws Throwable {doTest();}
 
   private void doTest() throws Exception {
     myFixture.enableInspections(new MissingReturnInspection());

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/controlFlow/ControlFlowTest.java

@@ -44,6 +44,7 @@ public class ControlFlowTest extends LightCodeInsightFixtureTestCase {
   public void testTry7() throws Throwable { doTest(); }
   public void testWhile1() throws Throwable { doTest(); }
   public void testWhile2() throws Throwable { doTest(); }
+  public void testWhileNonConstant() throws Throwable { doTest(); }
   public void testIfInstanceofElse() throws Throwable { doTest(); }
 
   private static String dumpControlFlow(Instruction[] instructions) {
@@ -66,7 +67,7 @@ public class ControlFlowTest extends LightCodeInsightFixtureTestCase {
     final PsiElement start = file.findElementAt(model.hasSelection() ? model.getSelectionStart() : 0);
     final PsiElement end = file.findElementAt(model.hasSelection() ? model.getSelectionEnd() - 1 : file.getTextLength() - 1);
     final GrControlFlowOwner owner = PsiTreeUtil.getParentOfType(PsiTreeUtil.findCommonParent(start, end), GrControlFlowOwner.class, false);
-    final Instruction[] instructions = new ControlFlowBuilder().buildControlFlow(owner, null, null);
+    final Instruction[] instructions = new ControlFlowBuilder(getProject()).buildControlFlow(owner, null, null);
     final String cf = dumpControlFlow(instructions);
     assertEquals(input.get(1).trim(), cf.trim());
   }

plugins/groovy/testdata/groovy/controlFlow/while1.test

@@ -6,7 +6,7 @@ while (true) {
 -----
 0(1) element: null
 1(2) WRITE i
-2(3,7) element: WHILE statement
+2(3) element: WHILE statement
 3(4,5) element: IF statement
 4(7) READ i
 5(6) READ i

plugins/groovy/testdata/groovy/controlFlow/while2.test

@@ -6,7 +6,7 @@ while (true) {
 -----
 0(1) element: null
 1(2) WRITE i
-2(3,7) element: WHILE statement
+2(3) element: WHILE statement
 3(4,5) element: IF statement
 4(2) READ i
 5(6) READ i

plugins/groovy/testdata/groovy/controlFlow/whileNonConstant.test

@@ -0,0 +1,15 @@
+i = 0
+while (condition()) {
+   if (i > 10) break
+   i++
+}
+-----
+0(1) element: null
+1(2) WRITE i
+2(3) element: WHILE statement
+3(4,8) READ condition
+4(5,6) element: IF statement
+5(8) READ i
+6(7) READ i
+7(2) WRITE i
+8() element: null

plugins/groovy/testdata/groovy/refactoring/extractMethod/inter1.test

@@ -12,9 +12,10 @@ def i = 6
 println i
 -----
 def i = 6
-i = <caret>testMethod(i)
+i = testMethod()
 
-private int testMethod(int i) {
+private int testMethod() {
+  int i
   while (true) {
     println "preved"
     i = 42

plugins/groovy/testdata/highlighting/missingReturn/EndlessLoop.groovy

@@ -0,0 +1,5 @@
+def foo() {
+  while (true) {
+    return 239
+  }
+}