moditect#67 Putting module-info.class to JAR root by default;

See the discussion in moditect#68 and related JDK bug https://bugs.openjdk.java.net/browse/JDK-8207162.

Author: gunnarmorling

core/src/main/java/org/moditect/commands/AddModuleInfo.java

@@ -40,6 +40,8 @@
  */
 public class AddModuleInfo {
 
+    private static final String NO_JVM_VERSION = "base";
+
     private final String moduleInfoSource;
     private final String mainClass;
     private final String version;
@@ -54,11 +56,11 @@ public AddModuleInfo(String moduleInfoSource, String mainClass, String version,
         this.version = version;
         this.inputJar = inputJar;
         this.outputDirectory = outputDirectory;
-        if (jvmVersion == null) {
-            // By default, put module descriptor in "META-INF/versions/9" for maximum backwards compatibility
-            this.jvmVersion = Integer.valueOf(9);
-        }
-        else if (jvmVersion.equals("base")) {
+
+        // #67 It'd be nice to use META-INF/services/9 by default to avoid conflicts with legacy
+        // classpath scanners, but this causes isses with subsequent jdeps invocations if there
+        // are MR-JARs and non-MR JARs passed to it due to https://bugs.openjdk.java.net/browse/JDK-8207162
+        if (jvmVersion == null || jvmVersion.equals(NO_JVM_VERSION)) {
             this.jvmVersion = null;
         }
         else {
@@ -69,7 +71,7 @@ else if (jvmVersion.equals("base")) {
                 }
             }
             catch (NumberFormatException e) {
-                throw new IllegalArgumentException("Invalid JVM Version: " + jvmVersion);
+                throw new IllegalArgumentException("Invalid JVM Version: " + jvmVersion + ". Allowed values are 'base' and integer values >= 9." );
             }
         }
         this.overwriteExistingFiles = overwriteExistingFiles;

core/src/main/java/org/moditect/commands/GenerateModuleInfo.java

@@ -376,14 +376,17 @@ private Map<String, Boolean> generateModuleInfo() throws AssertionError {
             command.add( modules.toString() );
             command.add( "--module-path" );
             command.add( modulePath.toString() );
-
-            command.addAll( jdepsExtraArgs );
         }
 
+        command.addAll( jdepsExtraArgs );
         command.add( inputJar.toString() );
 
         log.debug( "Running jdeps " + String.join(  " ", command ) );
-        jdeps.run( System.out, System.err, command.toArray( new String[0] ) );
+        int result = jdeps.run( System.out, System.err, command.toArray( new String[0] ) );
+
+        if (result != 0) {
+            throw new IllegalStateException("Invocation of jdeps failed: jdeps " + String.join(  " ", command ) );
+        }
 
         return optionalityPerModule;
     }