empty filter in resources does not work with java 8

pitest-entry/src/test/java/com/example/emptyreturns/AlreadyReturnsEmptyOptionalInTryWithResourcesBlock.java

@@ -0,0 +1,18 @@
+package com.example.emptyreturns;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Optional;
+
+public class AlreadyReturnsEmptyOptionalInTryWithResourcesBlock {
+    public Optional<String> a() throws IOException {
+        try(ByteArrayOutputStream os = new ByteArrayOutputStream()) {
+            Double.parseDouble("12");
+            if (os.size() > 42) {
+                return Optional.empty();
+            }
+            return Optional.of("foo");
+        }
+    }
+
+}

pitest-entry/src/test/java/org/pitest/mutationtest/build/intercept/equivalent/EquivalentReturnMutationFilterTest.java

@@ -1,15 +1,16 @@
 package org.pitest.mutationtest.build.intercept.equivalent;
 
+import com.example.emptyreturns.AlreadyReturnsEmptyOptionalInTryWithResourcesBlock;
+import org.junit.Ignore;
 import org.junit.Test;
 import org.pitest.mutationtest.build.InterceptorType;
 import org.pitest.mutationtest.build.MutationInterceptor;
 import org.pitest.mutationtest.build.intercept.javafeatures.FilterTester;
 import org.pitest.mutationtest.engine.gregor.mutators.returns.EmptyObjectReturnValsMutator;
 import org.pitest.mutationtest.engine.gregor.mutators.returns.NullReturnValsMutator;
 import org.pitest.mutationtest.engine.gregor.mutators.returns.PrimitiveReturnsMutator;
+import org.pitest.util.CurrentRuntime;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -19,14 +20,15 @@
 import java.util.stream.Stream;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assume.assumeTrue;
 import static org.pitest.mutationtest.engine.gregor.mutators.returns.BooleanFalseReturnValsMutator.FALSE_RETURNS;
 import static org.pitest.mutationtest.engine.gregor.mutators.returns.BooleanTrueReturnValsMutator.TRUE_RETURNS;
 
 public class EquivalentReturnMutationFilterTest {
 
   MutationInterceptor testee = new EquivalentReturnMutationFilter().createInterceptor(null);
 
-  FilterTester verifier = new FilterTester("", this.testee, PrimitiveReturnsMutator.PRIMITIVE_RETURNS
+  FilterTester verifier = new FilterTester("emptyReturns/{0}_{1}", this.testee, PrimitiveReturnsMutator.PRIMITIVE_RETURNS
                                                      , EmptyObjectReturnValsMutator.EMPTY_RETURNS
                                                      , NullReturnValsMutator.NULL_RETURNS
                                                      , FALSE_RETURNS
@@ -199,9 +201,19 @@ public void filtersEquivalentOptionalMutantsInTryBlocks() {
 
   @Test
   public void filtersEquivalentOptionalMutantsInTryWithResourcesBlocks() {
+    // skip test if we are running/compiling with java 8 as out analysis can't yet
+    // handle the bytecode
+    assumeTrue(CurrentRuntime.version() >= 9);
     verifier.assertFiltersNMutationFromClass(1, AlreadyReturnsEmptyOptionalInTryWithResourcesBlock.class);
   }
 
+  @Test
+  @Ignore("need more complex analysis")
+  public void filtersEquivalentOptionalMutantsInTryWithResourcesBlocksForOtherCompilers() {
+    // javac sample is for java 8
+    verifier.assertFiltersNMutationFromSample(1, "AlreadyReturnsEmptyOptionalInTryWithResourcesBlock");
+  }
+
   @Test
   public void filtersEquivalentStreamMutants() {
     verifier.assertFiltersNMutationFromClass(1, AlreadyReturnsEmptyStream.class);
@@ -435,19 +447,6 @@ public Optional<String> a() {
   }
 }
 
-class AlreadyReturnsEmptyOptionalInTryWithResourcesBlock {
-  public Optional<String> a() throws IOException {
-    try(ByteArrayOutputStream os = new ByteArrayOutputStream()) {
-      Double.parseDouble("12");
-      if (os.size() > 42) {
-        return Optional.empty();
-      }
-      return Optional.of("foo");
-    }
-  }
-
-}
-
 class AlreadyReturnsEmptyStream {
   public Stream<String> a() {
     return Stream.empty();

pitest-entry/src/test/java/org/pitest/util/CurrentRuntime.java

@@ -0,0 +1,17 @@
+package org.pitest.util;
+
+public class CurrentRuntime {
+
+    public static int version() {
+        String version = System.getProperty("java.version").replace("-ea", "");
+        if (version.startsWith("1.")) {
+            version = version.substring(2, 3);
+        } else {
+            int dot = version.indexOf(".");
+            if (dot != -1) {
+                version = version.substring(0, dot);
+            }
+        }
+        return Integer.parseInt(version);
+    }
+}