exec-maven-plugin says cannot run specified program, even though it is on the PATH

Question

Edit 20140716:

Solution found

tl;dr = exec-maven-plugin does not recognise .cmd files, but only .bat file

Answer 1

I dug into the source code of exec-maven-plugin and found this snippet.

From the source of ExecMojo#getExecutablePath:

    CommandLine toRet;
    if ( OS.isFamilyWindows() && exec.toLowerCase( Locale.getDefault() ).endsWith( ".bat" ) )
    {
        toRet = new CommandLine( "cmd" );
        toRet.addArgument( "/c" );
        toRet.addArgument( exec );
    }
    else
    {
        toRet = new CommandLine( exec );
    }

I compared this to another plugin that ran grunt tasks from maven, and found this

        if (isWindows()) {
            command = "cmd /c " + command;
        }

... and that worked for me. So essentially the latter worked because all commands in WIndows were prepended with cmd /c, whereas the exec-maven-plugin did not, because it only did so for file ending in .bat.

Looking in C:\Users\USER\AppData\Roaming\npm, I see:

• node_modules (folder)
• grunt (unix script file)
• grunt.cmd (windows script file)

When I rename grunt.cmd --> grunt.bat, this solves the problem, and exec-maven-plugin is able to run this command.

(this also applies to other executables created using npm install -g, such as bower and yo)