From: "Mark L." <marcuslamb@...>
Date: 2011-01-25T20:44:28+09:00
Subject: Re: FileUtils writing to stderr

Hi Eric,

I see your point. I should be able to check the return code for errors.
This would make the ant task even simpler as I would just have to set
the 'failonerror' flag.

I guess my question above was trying to find another way of doing this
because initially the return code was returning 0 when I was not
expecting it.

After reading your comments I've gone back to look at the code to see if
I could pinpoint where it was going wrong (you'll have to forgive me -
I'm new to ruby and am modifying a script written by someone else)

I traced the problem to a 'system' command. We are using a javascript
closure compiler to minify some javascript. It would fail if there was a
syntax error in the javascript - but the rake script would exit
normally. The original piece of code looked like:

system `#{JAVA_CMD} -jar #{JS_ROOT}/lib/compiler.jar --js=#{src}
--js_output_file=#{dst}`

and then the rake script carried on as normal. I then tried to capture
the $? of the command and raise an exception if it was non-zero.
Unfortunately, as it stands the above command always returns a non-zero
response. I eventually figured out that it was the back-ticks that was
causing the issue and so my final solution was to do this:

system("#{JAVA_CMD} -jar #{JS_ROOT}/lib/compiler.jar --js=#{src}
--js_output_file=#{dst}")
   # Raise an exception if the compiler fails
   if( !$?.success? )
     raise "Closure Compiler failed to compile javascript"
   end

and this finally seemed to resolve my problem.

Thanks for the response,
Mark.

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