Having trouble with original_year and Zero plugin

[01tot10]

I recently discovered the original_year field for tracks and albums, and would like to show it instead of (release) year in query results. However, I'm having some trouble with getting the field to show up correctly, and I'm getting increasingly confused about the expected behaviour. The confusion stems from me trying to deal with a number of (supposedly) incorrectly set original_year fields for some library items, and not understanding how they should be set / unset / emptied. The underlying bigger plan would be to unset/empty out the (supposedly) incorrectly set fields, and possibly setup a logic for showing year instead of original_year in query results when the latter field is unset / empty. See the use case below for details.

Use case

My album_format and item_format configurations are as follows:

> beet config|grep "format_"
format_album: $albumartist - $album | [$label, $original_year] $genre | $format
format_item: $artist - $album - $title | [$label, $original_year] $genre | $format

An example of a correctly rendering item looks as follows:

> beet ls -a album:"Ike Yard"     
Ike Yard - Ike Yard | [Desire Records, 1982] Synth/Wave | FLAC

Notice the existence of both year and original_year properties as a detail:

> beet info -a -i 'album,year,original_year' album:"Ike Yard" 
...
        album: Ike Yard
original_year: 1982
         year: 2012

However, some items have something off with the original_year field, making them look as follows:

> beet ls -a album:"5XOD"        
Five Times Of Dust - 5XOD | [Domestica, 0000] Synth/Wave | MP3

The relevant fields are set to:

> beet info -a -i 'album,year,original_year' album:"5XOD"    
...
        album: 5XOD
original_year: 0000
         year: 2015

And for the singular track in the album

> beet info -i 'album,track,year,original_year' album:"5XOD"
...
        album: 5XOD
original_year: 0
        track: 1
         year: 2015

I can remove the seemingly incorrectly set original_year field for the singular track using Zero Plugin by

> beet -v zero album:"5XOD"              
user configuration: ...
data directory: ...
plugin paths: []
Loading plugins: discogs, duplicates, edit, fetchart, info, inline, random, replaygain, smartplaylist, web, zero
fetchart: google: Disabling art source due to missing key
fetchart: lastfm: Disabling art source due to missing key
inline: adding album field format
Sending event: pluginload
library database: ...
library directory: ...
Sending event: library_opened
Parsed query: AndQuery([SubstringQuery('album', '5XOD', fast=True)])
Parsed sort: NullSort()
zero: original_year: 0 -> None
Sending event: write
Sending event: after_write
Sending event: database_change
Parsed query: AndQuery([DateQuery('added', '-1w..', fast=True)])
Parsed sort: NullSort()
Sending event: cli_exit

After this, the field is not shown any more:

beet info -i 'album,track,year,original_year' album:"5XOD"
...
album: 5XOD
track: 1
 year: 2015

However, querying for the track still shows original_year as before, as shown below. This might have to do with no logic setup so far for dealing with unset fields.

> beet ls album:"5XOD"                                      
Five Times Of Dust - 5XOD - Negativ Terminal Data | [Domestica, 0000] Synth/Wave | MP3

Also, checking for the value of original_year using the edit command shows:

> beet edit --all album:"5XOD"
(in text editor)
...
original_year: 0
...

.... which was the value it was set to before running the Zero Plugin. This makes me somewhat confused, not having the big picture (is it a placeholder flag for an unset field?).

Finally, as I'm more interested in albums, the Zero plugin doesn't seem to handle the -a flag, and thus I can't modify the album at all:

> beet zero -a album:"5XOD"
Usage: beet zero [options]

beet zero: error: no such option: -a

... and as such, my original problematic query output remains:

beet ls -a album:"5XOD"     
Five Times Of Dust - 5XOD | [Domestica, 0000] Synth/Wave | MP3

At this point, I'm already feeling stuck and confused, and would like to have some external feedback on what is going on.

Thanks for your input!