Introduce a DEFAULT visibility to indicate unspecified

core/src/main/java/org/jruby/anno/AnnotationBinder.java

@@ -330,7 +330,7 @@ public void processMethodDeclaration(ExecutableElement method) {
             String implClass = anno.meta() ? "singletonClass" : "cls";
 
             String baseName = getBaseName(anno.name(), method);
-            out.println("        javaMethod = new " + annotatedBindingName + "(" + implClass + ", Visibility." + anno.visibility() + ", \"" + baseName + "\");");
+            out.println("        javaMethod = new " + annotatedBindingName + "(" + implClass + ", Visibility." + anno.visibility().getDefaultVisibilityFor(baseName) + ", \"" + baseName + "\");");
             out.println("        populateMethod(javaMethod, " +
                     join(AnnotationHelper.getArityValue(anno, actualRequired),
                             quote(method.getSimpleName()),
@@ -367,7 +367,7 @@ public void processMethodDeclarationMulti(ExecutableElement method) {
             String implClass = anno.meta() ? "singletonClass" : "cls";
 
             String baseName = getBaseName(anno.name(), method);
-            out.println("        javaMethod = new " + annotatedBindingName + "(" + implClass + ", Visibility." + anno.visibility() + ", \"" + baseName + "\");");
+            out.println("        javaMethod = new " + annotatedBindingName + "(" + implClass + ", Visibility." + anno.visibility().getDefaultVisibilityFor(baseName) + ", \"" + baseName + "\");");
             out.println("        populateMethod(javaMethod, " +
                         join(-1,
                                 quote(method.getSimpleName()),

core/src/main/java/org/jruby/anno/IndyBinder.java

@@ -392,8 +392,9 @@ public void processMethodDeclarationMulti(List<ExecutableElement> methods) {
         mv.dup();
 
         mv.aload(implClass);
-        mv.getstatic(p(Visibility.class), anno.visibility().name(), ci(Visibility.class));
-        mv.ldc(AnnotationBinder.getBaseName(anno.name(), methods.get(0)));
+        String baseName = AnnotationBinder.getBaseName(anno.name(), methods.get(0));
+        mv.getstatic(p(Visibility.class), anno.visibility().getDefaultVisibilityFor(baseName).name(), ci(Visibility.class));
+        mv.ldc(baseName);
         mv.ldc(encodeSignature(0, 0, 0, 0, 0, true, false));
         mv.ldc(true);
         mv.ldc(anno.notImplemented());

core/src/main/java/org/jruby/anno/JRubyMethod.java

@@ -81,7 +81,7 @@
     /**
      * The visibility of this method.
      */
-    Visibility visibility() default Visibility.PUBLIC;
+    Visibility visibility() default Visibility.DEFAULT;
 
     /**
      * What, if anything, method reads from caller's frame

core/src/main/java/org/jruby/internal/runtime/methods/InvocationMethodFactory.java

@@ -357,13 +357,13 @@ public JavaMethod constructJavaMethod(RubyModule implementationClass, JavaMethod
             // Old constructor with no name, use thread-local to pass it.
             JavaMethod.NAME_PASSER.set(name);
             try {
-                ic = (JavaMethod) c.getConstructor(RubyModule_and_Visibility).newInstance(implementationClass, desc.anno.visibility());
+                ic = (JavaMethod) c.getConstructor(RubyModule_and_Visibility).newInstance(implementationClass, desc.anno.visibility().getDefaultVisibilityFor(name));
             } finally {
                 JavaMethod.NAME_PASSER.remove();
             }
         } else {
             // New constructor with name.
-            ic = (JavaMethod) c.getConstructor(RubyModule_and_Visibility_and_Name).newInstance(implementationClass, desc.anno.visibility(), name);
+            ic = (JavaMethod) c.getConstructor(RubyModule_and_Visibility_and_Name).newInstance(implementationClass, desc.anno.visibility().getDefaultVisibilityFor(name), name);
         }
         return ic;
     }

core/src/main/java/org/jruby/internal/runtime/methods/InvokeDynamicMethodFactory.java

@@ -120,7 +120,7 @@ public DynamicMethod getAnnotatedMethod(final RubyModule implementationClass, fi
 
         return new HandleMethod(
                 implementationClass,
-                desc1.anno.visibility(),
+                desc1.anno.visibility().getDefaultVisibilityFor(desc1.name),
                 desc1.name,
                 (min == max) ?
                         org.jruby.runtime.Signature.from(min, 0, 0, 0, 0, org.jruby.runtime.Signature.Rest.NONE, -1).encode() :

core/src/main/java/org/jruby/runtime/Visibility.java

@@ -27,7 +27,7 @@
 package org.jruby.runtime;
 
 public enum Visibility {
-    PUBLIC, PROTECTED, PRIVATE, MODULE_FUNCTION, UNDEFINED;
+    PUBLIC, PROTECTED, PRIVATE, MODULE_FUNCTION, UNDEFINED, DEFAULT;
     private static final Visibility[] VALUES = values();
 
     public boolean isPublic() {
@@ -49,4 +49,18 @@ public boolean isModuleFunction() {
     public static Visibility[] getValues() {
         return VALUES;
     }
+
+    public Visibility getDefaultVisibilityFor(String name) {
+        switch (this) {
+            case DEFAULT:
+                switch (name) {
+                    case "initialize":
+                    case "initialize_copy":
+                       return PRIVATE;
+                }
+                return PUBLIC;
+            default:
+                return this;
+        }
+    }
 }

core/src/test/java/org/jruby/test/TestMethodFactories.java

@@ -30,12 +30,15 @@
 
 import org.jruby.CompatVersion;
 import org.jruby.Ruby;
+import org.jruby.RubyClass;
 import org.jruby.RubyMethod;
 import org.jruby.RubyModule;
+import org.jruby.RubyObject;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.exceptions.ArgumentError;
 import org.jruby.internal.runtime.methods.DynamicMethod;
 import org.jruby.runtime.ThreadContext;
+import org.jruby.runtime.Visibility;
 import org.jruby.runtime.builtin.IRubyObject;
 
 
@@ -166,4 +169,37 @@ public void testVersionedMethods() {
         assertNotNull(mod.searchMethod("method"));
     }
 
+    public void testDefaultVisibility() {
+        RubyClass cls = runtime.defineClass("NoVisibilityInitialize", runtime.getObject(), NoVisibilityInitialize::new);
+
+        cls.defineAnnotatedMethods(NoVisibilityInitialize.class);
+
+        assertEquals(Visibility.PRIVATE, cls.searchMethod("initialize").getVisibility());
+        assertEquals(Visibility.PRIVATE, cls.searchMethod("initialize_copy").getVisibility());
+        assertEquals(Visibility.PUBLIC, cls.searchMethod("some_other_method").getVisibility());
+    }
+
+    public static class NoVisibilityInitialize extends RubyObject {
+        public NoVisibilityInitialize(Ruby runtime, RubyClass metaClass) {
+            super(metaClass);
+        }
+
+        // intentionally no visibility
+        @JRubyMethod
+        public IRubyObject initialize(ThreadContext context) {
+            return context.nil;
+        }
+
+        // intentionally no visibility
+        @JRubyMethod
+        public IRubyObject initialize_copy(ThreadContext context, IRubyObject copy) {
+            return context.nil;
+        }
+
+        @JRubyMethod
+        public IRubyObject some_other_method(ThreadContext context) {
+            return context.nil;
+        }
+    }
+
 }