open() and copy() misbehave if the destination file is readonly

[ghost]

This seems to be happening because Writer(), in writer.js, is returning Q(self) instead of a deferred 'begin' promise, as Reader() does.

If I amend Writer, as below, using the open event, then it will work correctly for both writable and non-writable files (unit-tests pass). However, as far as I am aware HTTP streams do not emit the open event, so I'm not sure if this "fix" is the correct approach - happy to look at some other approach if anyone can offers hints.

(When using the open event in the Reader(), HTTP unit-tests fail, which confirms that reading HTTP streams does not emit the open event. Given that the unit-tests pass above, I assume writing HTTP streams via unit-tests is not done or does not invoke Writer().)

?

function Writer(_stream, charset) {
    var self = Object.create(Writer.prototype);

    if (charset && _stream.setEncoding) // TODO complain about inconsistency
        _stream.setEncoding(charset);

    var begin = Q.defer();
    var drained = Q.defer();

    _stream.on("error", function (reason) {
        begin.reject(reason);
    });

    _stream.on("open", function () {
        begin.resolve(self);
    });

    _stream.on("drain", function () {
        drained.resolve();
        drained = Q.defer();
    });

    :.............. (rest of code)................

    return begin.promise;
    //return Q(self); // todo returns the begin.promise
}