comparison mercurial/windows.py @ 47038:5b3513177f2b stable

util: avoid echoing the password to the console on Windows py3 (issue6446)

The `getpass.getpass()` implementation on Windows first checks if `sys.stdin`
and `sys.__stdin__` are the same object.  It's not on py3 because the former is
replaced in dispatch.py with something that doesn't normalize '\n' to '\r\n'.
When they aren't the same object, it simply calls `sys.stdin.readline()` instead
of the mscvrt functions that read the input characters before they are echoed.

This simply copies the `getpass.win_getpass()` implementation without the stdin
check, and byteifies around the edges.  I'm not sure if there's a reasonable
replacement for the check that we could implement.  When echoing input into the
hg command, the `ui.interactive()` check causes `ui.getpass()` to bail before
getting here.  If the proper config switches are used to bypass that and call
this, the process stalls until '\n' is input into the console.  So there could
be a deadlock here when run by another command if the wrong config settings are
applied.

Differential Revision: https://phab.mercurial-scm.org/D10708

47037:3af293735d0f

def _isatty(fp):
    try:
        return fp.isatty()
    except AttributeError:
        return False


class winstdout(object):
    """Some files on Windows misbehave.

47038:5b3513177f2b

def _isatty(fp):
    try:
        return fp.isatty()
    except AttributeError:
        return False


def get_password():
    """Prompt for password with echo off, using Windows getch().

    This shouldn't be called directly- use ``ui.getpass()`` instead, which
    checks if the session is interactive first.
    """
    pw = ""
    while True:
        c = msvcrt.getwch()
        if c == '\r' or c == '\n':
            break
        if c == '\003':
            raise KeyboardInterrupt
        if c == '\b':
            pw = pw[:-1]
        else:
            pw = pw + c
    msvcrt.putwch('\r')
    msvcrt.putwch('\n')
    return encoding.strtolocal(pw)


class winstdout(object):
    """Some files on Windows misbehave.