Cannot set "-Werror" javac option when using Groovyc ant task.

-X options become -FX in joint compilation here: https://github.com/groovy/groovy-core/blob/GROOVY_1_9_BETA_3/src/main/org/codehaus/groovy/ant/Groovyc.java#L751

javac -help doesn't show -W options. Is "-Werror" an officially supported option?

http://weblogs.java.net/blog/tball/archive/2006/11/get_medieval_on.html calls 'Werror' a hidden option.

Although, it should probably do no harm to allow it if Ant allows it.

If no one has any objection, I can add jointOptions.add(optionStr.replace("-W", "-FW")); to support -Werror in joint compilation.

what -W options do exist?

>> what -W options do exist?

Looking at JDK make files, I can see options like:

-Wno-unused 
-Wno-parentheses
-Werror

But why? Does the decision depend on what options are there? Or is it more like being a pass through to Javac like Ant, and not bother about the specifics of the options?

The amount was interesting to me to see if we do that for a general thing or for just a few options. -X is used with in many combinations, so it is really worth it. -W options is partly undocumented and kind of non-official. Also there exists a way to get this working.

Roshan and Luke, you guys think this is really worth it?

One more thing to say... I actually think this kind of forwarding is a bit problematic for us. Adding -W as a forwarding means we cannot use it ourselves. I actually would have been against the -X version, but I missed that issue I think. The only reason I am considering this here at all, is because we have -X. Which makes it a bit a weak argumentation chain for me.

Jochen: so are you proposing that we do nothing and require users to prefix the args themselves?

I am not yet proposing, I want more to see your opinions on this

Anything short of being able to just specify the same args I would specify to javac is going to be confusing. It would just be implementation detail leaking through.

but two things speak against that argumentation:
(1) not all java compilers support that option
(2) you give this option to the groovy compiler in the first place, not the java compiler. Controlling the java compiler is supposed to work with -F and -J.

Not sure that (1) is relevant, if the Java compiler doesn't support it should complain and not Groovy.

As for (2), how so? If I nest a <javac> element I would expect as a user for it to be the same as a regular <javac> element. The fact that it behaves differently because it is nested inside <groovyc> is not obvious at all (and shouldn't be).

I also happen to think that Groovy should not block -W options in reaching javac from nested <javac> elements.

It seems inconsistent that in joint compilation, a user can pass one option to javac as <compilerarg value="-Xlint:all">, and for other, he needs to do <compilerarg value="-FWerror">.

I guess there's not many other options than just amending the list as new args are found.

+1 to Luke's suggestion. Otherwise it is un-necessarily stuck holding even the options that we know about.

ok then.. Roshan, you want to take the issue?

Done. In joint compilation, -W options are now passed to javac like -X options.

Nice one Roshan, thanks.