Stream feeder and consumer threads should be replaced with ProcessBuilder->inheritIO to allow child processes to die/be killed on Windows when hitting CTRL-C

[jjYBdx4IL]

tbroyer/gwt-maven-plugin#110 (comment)

I played around with plexus-utils to find out why my own test case works, but plexus-utils doesn't. Answer: it seems to be related to the stream pumpers/feeders. When I replace Runtime.exec() with ProcessBuilder and use its inheritIO() instead, the child process goes away as expected when the parent process calls Process->destroy() on it. Specifically using Redirect.INHERIT on the child's STDIN fixes the issue.

Commandline:

/**
 * Executes the command.
 */
public Process execute()
    throws CommandLineException
{
    // TODO: Provided only for backward compat. with <= 1.4
    verifyShellState();

    Process process;

    // addEnvironment( "MAVEN_TEST_ENVAR", "MAVEN_TEST_ENVAR_VALUE" );

    String[] environment = getEnvironmentVariables();

    File workingDir = shell.getWorkingDirectory();

    ProcessBuilder pb = new ProcessBuilder(getCommandline());
    pb.directory(workingDir);
    pb.inheritIO();
    if (environment != null) {
        for (String s : environment) {
            String[] kv = s.split("=", 2);
            pb.environment().put(kv[0], kv[1]);
        }
    }
    
    try
    {
        if ( workingDir != null ) {
            if ( !workingDir.exists() )
            {
                throw new CommandLineException( "Working directory \"" + workingDir.getPath()
                    + "\" does not exist!" );
            }
            else if ( !workingDir.isDirectory() )
            {
                throw new CommandLineException( "Path \"" + workingDir.getPath()
                    + "\" does not specify a directory." );
            }
        }

        process = pb.start();
    }
    catch ( IOException ex )
    {
        throw new CommandLineException( "Error while executing process.", ex );
    }

    return process;
}

[olamy]

sounds a good idea and to be tested!
could you make a pr with your proposal?

[jjYBdx4IL]

While fixing gwt-maven-plugin, I found it easier to just use ProcessBuilder there. Do you think the command line exec stuff in plexus-utils is still necessary as of Java 7?

[michael-o]

@jjYBdx4IL I think most not, espcially launching subshells is a mess.