scripts: runner: add internal DEBUG to core

import subprocess

# Turn on to enable just printing the commands that would be run,

# without actually running them. This can break runners that are expecting

# output or if one command depends on another, so it's just for debugging.

DEBUG = False

class _DebugDummyPopen:

    def terminate(self):

        pass

    def wait(self):

        pass

def quote_sh_list(cmd):

    '''Transform a command from list into shell string form.'''

    fmt = ' '.join('{}' for _ in cmd)

        subprocess and check that it executed correctly, rather than

        using subprocess directly, to keep accurate debug logs.

        '''

        if self.debug:

        if DEBUG or self.debug:

            print(quote_sh_list(cmd))

        if DEBUG:

            return

        try:

            subprocess.check_call(cmd)

        except subprocess.CalledProcessError:

        '''

        if self.debug:

            print(quote_sh_list(cmd))

        if DEBUG:

            return b''

        try:

            return subprocess.check_output(cmd)

        except subprocess.CalledProcessError:

        elif system in {'Linux', 'Darwin'}:

            preexec = os.setsid

        if self.debug:

        if DEBUG or self.debug:

            print(quote_sh_list(cmd))

        if DEBUG:

            return _DebugDummyPopen()

        return subprocess.Popen(cmd, creationflags=cflags, preexec_fn=preexec)