fail early if javah is used with java 10+

WHATSNEW

@@ -52,6 +52,9 @@ Other changes:
 
  * added "javac10+" as new supported value for javac's compiler attribute.
 
+ * javah has been removed from Java 10. The task will now throw an
+   exception if you try to use it while running Java 10 or newer.
+
 Changes from Ant 1.9.8 TO Ant 1.9.9
 ===================================
 

manual/Tasks/javah.html

@@ -39,7 +39,8 @@ systems are used.</p>
   generate the native header files with a single step.</p>
 
 <p><b>Note</b> the <code>javah</code> has been deprecated as of Java 9
-  and is scheduled to be removed with Java 10.</p>
+  and removed as of Java 10. Trying to use it with Java10 will
+  fail.</p>
 
 <p>It is possible to use different compilers. This can be selected
 with the <code>implementation</code> attribute or a nested element.  <a

src/main/org/apache/tools/ant/taskdefs/optional/javah/JavahAdapterFactory.java

@@ -89,6 +89,10 @@ public class JavahAdapterFactory {
         } else if ((JavaEnvUtils.isGij() && choice == null)
             || Gcjh.IMPLEMENTATION_NAME.equals(choice)) {
             return new Gcjh();
+        } else if (JavaEnvUtils.isAtLeastJavaVersion("10") &&
+                   (choice == null || ForkingJavah.IMPLEMENTATION_NAME.equals(choice))) {
+            throw new BuildException("javah does not exist under Java 10 and higher,"
+                + " use the javac task with nativeHeaderDir instead");
         } else if ((JavaEnvUtils.isAtLeastJavaVersion(JavaEnvUtils.JAVA_9)
                     && choice == null)
                    || ForkingJavah.IMPLEMENTATION_NAME.equals(choice)) {

src/tests/antunit/taskdefs/optional/javah-test.xml

@@ -101,12 +101,12 @@ public class Foo {
     </presetdef>
   </target>
 
-  <target name="testSimpleCompile" depends="-setupForRealJavahTests">
+  <target name="testSimpleCompile" depends="-setupForRealJavahTests" unless="jdk10+">
     <javah-single/>
     <au:assertFileExists file="${output}/org_example_Foo.h"/>
   </target>
 
-  <target name="testCompileUsingFileset" depends="-setupForRealJavahTests">
+  <target name="testCompileUsingFileset" depends="-setupForRealJavahTests" unless="jdk10+">
     <javah-fileset/>
     <au:assertFileExists file="${output}/org_example_Foo.h"/>
   </target>
@@ -123,13 +123,21 @@ public class Foo {
     <au:assertFileExists file="${output}/org_example_Foo.h"/>
   </target>
 
-  <target name="testSimpleCompileForking" depends="-setupForRealJavahTests">
+  <target name="testSimpleCompileForking" depends="-setupForRealJavahTests" unless="jdk10+">
     <javah-single implementation="forking"/>
     <au:assertFileExists file="${output}/org_example_Foo.h"/>
   </target>
 
-  <target name="testCompileUsingFilesetForking" depends="-setupForRealJavahTests">
+  <target name="testCompileUsingFilesetForking" depends="-setupForRealJavahTests" unless="jdk10+">
     <javah-fileset implementation="forking"/>
     <au:assertFileExists file="${output}/org_example_Foo.h"/>
   </target>
+
+  <target name="testSimpleCompileFailsOnJava10+" depends="-setupForRealJavahTests"
+          if="jdk10+">
+    <au:expectfailure>
+      <javah-single/>
+    </au:expectfailure>
+  </target>
+
 </project>

src/tests/junit/org/apache/tools/ant/taskdefs/optional/JavahTest.java

@@ -18,6 +18,8 @@
 package org.apache.tools.ant.taskdefs.optional;
 
 import org.apache.tools.ant.BuildFileRule;
+import org.apache.tools.ant.util.JavaEnvUtils;
+import org.junit.Assume;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
@@ -47,6 +49,7 @@ public class JavahTest {
 
     @Test
     public void testSimpleCompile() {
+        Assume.assumeFalse(JavaEnvUtils.isAtLeastJavaVersion("10"));
         buildRule.executeTarget("simple-compile");
         assertTrue(new File(buildRule.getProject().getProperty("output"), "org_example_Foo.h")
                 .exists());
@@ -54,6 +57,7 @@ public class JavahTest {
 
     @Test
     public void testCompileFileset() {
+        Assume.assumeFalse(JavaEnvUtils.isAtLeastJavaVersion("10"));
         buildRule.executeTarget("test-fileset");
         assertTrue(new File(buildRule.getProject().getProperty("output"), "org_example_Foo.h").exists());
     }