defining @property.setter for a property defined in superclass

Question

I Have a set of classes which represent audio tracks an their metadata. For some of the file formats I only support reading tags, for others writing is also implemented.

class ReadableTrack(object):
    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod
    def _get_artist(self):
        raise NotImplementedError

    @property
    def artist(self):
        return self._get_artist()


class DsfTrack(ReadableTrack):
    """
        Support for DSF files
    """
    def _get__get_artist(self):
        pass  # code here

File formats to which writing meta is supported are derived from a subclass of ReadableTrack which implements setters for tags

class WritableTrack(ReadableTrack):
    """
        A track to which metadata can also be written.
    """

    @abc.abstractmethod
    def _set_artist(self, artist):
        raise NotImplementedError

    @artist.setter
    def artist(self, value):
        self._set_artist()


class FlacTrack(WritableTrack):
    """
        Class to get the metadata from .flac file extensions
    """

    def _get_artist(self):
        pass  # code here

    def _set_artist(self, value):
        pass  # code here

Unfortunatly, the above will cause an the following error:

File "/system/audio/metadata/Track/FlacTrack.py", line 11, in <module>
    from system.audio.metadata.Track import WritableTrack
  File "/system/audio/metadata/Track/__init__.py", line 23, in <module>
    from system.audio.metadata.Track.WritableTrack import WritableTrack
  File "/system/audio/metadata/Track/WritableTrack.py", line 13, in <module>
    class WritableTrack(ReadableTrack):
  File "/system/audio/metadata/Track/WritableTrack.py", line 171, in WritableTrack
    @artist.setter
NameError: name 'artist' is not defined

Which can be "workedaround" by redefining the the artist property in WritableTrack like so:

class WritableTrack2(ReadableTrack):
    """
        A track to which metadata can also be written.
    """

    @abc.abstractmethod
    def _get_artist(self):
        raise NotImplementedError

    @abc.abstractmethod
    def _set_artist(self, value):
        raise NotImplementedError

    @property
    def artist(self):
        return self._get_artist()

    @artist.setter
    def artist(self, value):
        self._set_artist(value)

So basically in WritableTrack I can't define a @property.setter for a property defined in a superclass. The properties are defined in the superclasses because they include some I/O validation to ensure interface consistency between the various subclasses of ReadableTrack and WritableTrack. Re-defining the property is redundant and defeats the purpose of inheritance... I'd like to find the "correct" way of doing it. Any hints?

Reference the original property object on the parent class: `@ReadableTrack.artist.setter`. — Martijn Pieters, Jul 15 '16 at 17:34
@MartijnPieters -- Won't that just define `artist.__set__` on the original parent class (making the parent class writable too)? — mgilson, Jul 15 '16 at 17:36
@mgilson: no, the decorator *returns a new property object*; you get a new property object on the WritableTrack class with the getter inherited, and a new setter function. The parent class is unaffected. — Martijn Pieters, Jul 15 '16 at 17:36
@mgilson: see [How does the `@property` decorator work?](https://stackoverflow.com/a/17330273) — Martijn Pieters, Jul 15 '16 at 17:37
Interesting, you're right. At least, if we're to believe the "pure python" implementation on the descriptor page of the docs: https://docs.python.org/3/howto/descriptor.html (and I do). — mgilson, Jul 15 '16 at 17:38
@MartijnPieters Thanks for the awesome ninja-quick solution! — Emanuel Ey, Jul 15 '16 at 17:38

defining @property.setter for a property defined in superclass

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