How to Determine an mxmlc-compiled SWF File Was Built in Debug or Release Mode

Question

First of all, I'm NOT talking about if the player is a debugger or not. (EDIT: it IS actually related to the debugger player)

I use mxmlc to compile a very simple swf file with -debug=false:

mac-108:tmp admin$ "/Applications/Adobe Flash Builder 4.7/sdks/4.6.0/bin/mxmlc" +configname flex -debug=true -static-link-runtime-shared-libraries=true Main.as
Loading configuration file /Applications/Adobe Flash Builder 4.7/sdks/4.6.0/frameworks/flex-config.xml
/Users/admin/tmp/Main.swf (987 bytes)
mac-108:tmp admin$

The Main.as:

package {
    import flash.display.MovieClip;
    import flash.text.*;

    public class Main extends MovieClip {

        public function Main() {
            // Reference: http://stackoverflow.com/questions/185477/determine-if-swf-is-in-a-debug-player-or-mode
            var st:String = new Error().getStackTrace();
            var isDebugBuild:Boolean = (st && st.search(/:[0-9]+]$/m) > -1);
            var my_st:String = "st: " + (st == null ? 'Null' : st);
            var my_DR:String = isDebugBuild?"Debug":"Release";

            var obj:TextField = new TextField();
            obj.text = my_st + "\n" + my_DR;
            this.addChild(obj);
        }
    }
}

Then I open Main.swf in my Chrome browser, but I see:

st:Null
Release

Which is so weird that, apparently, I have set -debug=true, why does NOT the popular method to determine if an swf is in Debug or Release work.

However, if I move my code to the Flash Builder 4.7, it will give me the Debug output (instead of Release).

Answer 1

It turns out that when the SWF is built in Debug mode, in order to test if it's in debug mode, the Flash Player must also be a debugger using Capabilities.isDebugger.