Want to come up with a PR? The code for this is all in Ruby.

On Wed, Jun 19, 2013 at 3:02 PM, Phil Smith notifications@github.comwrote:

jrubyc is not sandboxing the name of its java method return value away
from the arguments names. Notice the double IRubyObject ruby_result below.

Perhaps prefix arguments with ruby_arg_?

$ jruby --version
jruby 1.7.4 (1.9.3p392) 2013-05-16 2390d3b on Java HotSpot(TM) 64-Bit Server VM 1.7.0_12-ea-b08 +indy [darwin-x86_64]
$ cat jrubyc_name_mangling.rb

class C
java_signature 'public int f(int result)'
def f(arg)
arg
endend

$ jrubyc --java --javac jrubyc_name_mangling.rb
/Users/phil/derp/C.java:65: error: variable ruby_result is already defined in method f(int)
IRubyObject ruby_result = Helpers.invoke(ruby.getCurrentContext(), this, "f", ruby_result);
^
1 error
$ cat C.java

import org.jruby.Ruby;import org.jruby.RubyObject;import org.jruby.runtime.Helpers;import org.jruby.runtime.builtin.IRubyObject;import org.jruby.javasupport.JavaUtil;import org.jruby.RubyClass;

public class C extends RubyObject {
private static final Ruby ruby = Ruby.getGlobalRuntime();
private static final RubyClass metaclass;

static {
    String source = new StringBuilder("class C\n" +
        "  java_signature 'public int f(int result)'\n" +
        "  def f(arg)\n" +
        "    arg\n" +
        "  end\n" +
        "end\n" +
        "").toString();
    __ruby__.executeScript(source, "jrubyc_name_mangling.rb");
    RubyClass metaclass = __ruby__.getClass("C");
    metaclass.setRubyStaticAllocator(C.class);
    if (metaclass == null) throw new NoClassDefFoundError("Could not load Ruby class: C");
    __metaclass__ = metaclass;
}

/**     * Standard Ruby object constructor, for construction-from-Ruby purposes.     * Generally not for user consumption.     *     * @param ruby The JRuby instance this object will belong to     * @param metaclass The RubyClass representing the Ruby class of this object     */
private C(Ruby ruby, RubyClass metaclass) {
    super(ruby, metaclass);
}

/**     * A static method used by JRuby for allocating instances of this object     * from Ruby. Generally not for user comsumption.     *     * @param ruby The JRuby instance this object will belong to     * @param metaclass The RubyClass representing the Ruby class of this object     */
public static IRubyObject __allocate__(Ruby ruby, RubyClass metaClass) {
    return new C(ruby, metaClass);
}

/**     * Default constructor. Invokes this(Ruby, RubyClass) with the classloader-static     * Ruby and RubyClass instances assocated with this class, and then invokes the     * no-argument 'initialize' method in Ruby.     */
public C() {
    this(__ruby__, __metaclass__);
    Helpers.invoke(__ruby__.getCurrentContext(), this, "initialize");
}


public int f(int result) {
    IRubyObject ruby_result = JavaUtil.convertJavaToRuby(__ruby__, result);
    IRubyObject ruby_result = Helpers.invoke(__ruby__.getCurrentContext(), this, "f", ruby_result);
    return (Integer)ruby_result.toJava(int.class);

}

}

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/812
.

At least with JRuby 9k, this is no bug is no longer present:

➜  sandbox  cat > name-mangler.rb
class C
  java_signature 'public int f(int result)'
  def f(arg)
    arg
  end
end
➜  sandbox  rvm use jruby@rubygems
Using /home/tyler/.rvm/gems/jruby-9.0.0.0 with gemset rubygems
➜  sandbox  jrubyc --java --javac name-mangler.rb 
➜  sandbox  ls
C.class  C.java  name-mangler.rb
➜  sandbox