zero: Removing images despite whitelisting images

Problem

Hello! New beets user here. Awesome project, thank you for creating it!

I run beets with the zero plugin in whitelist mode. I want to keep only a couple of metadata fields, including cover art.

Running this command in verbose (-vv) mode:

# The file contains a cover image 
$ eyeD3 /beets-test/Kontor Sunset Chill 2018/Kontor Sunset Chill 2018 CD 3 - 10 - Be Svendsen - Andromeda.mp3
ID3 v2.3:
title: Andromeda
...
FRONT_COVER Image: [Size: 171538 bytes] [Type: image/jpeg]

# Write metadata
$ beet -vv write andromeda
user configuration: /Users/agross/.config/beets/config.yaml
data directory: /Users/agross/.config/beets
plugin paths:
Sending event: pluginload
artresizer: method is (2, (7, 0, 10), False)
inline: adding item field maybe_disc
inline: adding item field maybe_soundtrack
library database: /Users/agross/Downloads/beets.db
library directory: /Users/agross/Downloads/beets-test
Sending event: library_opened
/beets-test/Kontor Sunset Chill 2018/Kontor Sunset Chill 2018 CD 3 - 10 - Be Svendsen - Andromeda.mp3
  tracktotal: 00 -> 20
  disctotal: 00 -> 03
  comp: False -> True
  mb_trackid:  -> 12171320-3-10
  mb_albumid:  -> 12171320
  mb_artistid:  -> 2282919
  mb_albumartistid:  -> 194
  albumtype:  -> Compilation, Mixed
  label:  -> Kontor Records
  mb_releasegroupid:  -> 0
  catalognum:  -> 1069674KON
  country:  -> Germany
  media:  -> CD
  disctitle:  -> Miami Sundowner Mix
  original_year: 0000 -> 2018
Sending event: write
zero: genres:  -> None
zero: genre:  -> None
zero: lyricist:  -> None
zero: composer:  -> None
zero: composer_sort:  -> None
zero: arranger:  -> None
zero: grouping:  -> None
zero: tracktotal: 20 -> None
zero: disctotal: 3 -> None
zero: lyrics:  -> None
zero: comments:  -> None
zero: bpm: 0 -> None
zero: comp: 1 -> None
zero: albumtype: Compilation, Mixed -> None
zero: label: Kontor Records -> None
zero: artist_sort:  -> None
zero: albumartist_sort:  -> None
zero: asin:  -> None
zero: catalognum: 1069674KON -> None
zero: disctitle: Miami Sundowner Mix -> None
zero: encoder:  -> None
zero: script:  -> None
zero: language:  -> None
zero: country: Germany -> None
zero: albumstatus:  -> None
zero: media: CD -> None
zero: albumdisambig:  -> None
zero: date:  -> None
zero: month: 0 -> None
zero: day: 0 -> None
zero: original_date:  -> None
zero: original_year: 2018 -> None
zero: original_month: 0 -> None
zero: original_day: 0 -> None
zero: artist_credit:  -> None
zero: albumartist_credit:  -> None
zero: art:  -> None
zero: mb_trackid: 12171320-3-10 -> None
zero: mb_releasetrackid:  -> None
zero: mb_albumid: 12171320 -> None
zero: mb_artistid: 2282919 -> None
zero: mb_albumartistid: 194 -> None
zero: mb_releasegroupid: 0 -> None
zero: acoustid_fingerprint:  -> None
zero: acoustid_id:  -> None
zero: rg_track_gain: None -> None
zero: rg_album_gain: None -> None
zero: rg_track_peak: None -> None
zero: rg_album_peak: None -> None
zero: r128_track_gain: None -> None
zero: r128_album_gain: None -> None
zero: initial_key: None -> None
Sending event: after_write
importadded: Write of item '/beets-test/Kontor Sunset Chill 2018/Kontor Sunset Chill 2018 CD 3 - 10 - Be Svendsen - Andromeda.mp3', selected item.added=1536234269.0
Sending event: database_change
Sending event: cli_exit

Led to this problem:

$ eyeD3 /beets-test/Kontor Sunset Chill 2018/Kontor Sunset Chill 2018 CD 3 - 10 - Be Svendsen - Andromeda.mp3
...
ID3 v2.3:
title: Andromeda
artist: Be Svendsen
album: Kontor Sunset Chill 2018
album artist: Various Artists
recording date: 2018
track: 10
disc: 3

The important bit seems to be zero: art: -> None in the output of beet write. This field isn't reported in beet fields, just like image.

Workaround

Add art to zero.keep_fields.

Setup

OS: macOS
Python version: Python 3.7.7
beets version: beets version 1.4.9
Turning off plugins made problem go away (yes/no): yes, the zero plugin

My configuration (output of beet config) is:

directory: /beets-test
library: ~/beets.db

import:
    copy: yes
    move: no
    write: no

replace:
    ':': ' -'
    \?: ''
    '[\\/]': _
    ^\.: _
    '[\x00-\x1f]': _
    '[<>:"\?\*\|]': _
    \s+$: ''
    ^\s+: ''

paths:
    default: $albumartist - $album%aunique{}/$albumartist - $album$maybe_disc - $track - $artist - $title
    comp: $album%aunique{}$maybe_soundtrack/$album$maybe_soundtrack$maybe_disc - $track - $artist - $title
    singleton: $artist - $title
per_disc_numbering: yes
id3v23: yes

format_item: $path
format_album: $path
art_filename: cover

plugins:
- importadded
- ftintitle
- zero
- badfiles
- discogs
- inline
- info
- fetchart
- embedart
item_fields:
    maybe_disc: u' CD %i' % (disc) if disctotal > 1 else u''
    maybe_soundtrack: u' O.S.T.' if albumtype == 'soundtrack' else u''
importadded:
    preserve_mtimes: yes
    preserve_write_mtimes: yes
fetchart:
    auto: yes
    cover_names: [cover, front]
    sources:
    - filesystem
    - amazon
    - coverart
    - itunes
    - albumart
    - wikipedia
    - google
    minwidth: 0
    maxwidth: 0
    enforce_ratio: no
    cautious: no
    google_key: REDACTED
    google_engine: 001442825323518660753:hrh5ch1gjzm
    fanarttv_key: REDACTED
    store_source: no
embedart:
    auto: yes
    ifempty: yes
    maxwidth: 2000
    remove_art_file: no
    compare_threshold: 0
zero:
    auto: yes
    update_database: no
    keep_fields:
    - albumartist
    - artist
    - album
    - disc
    - track
    - title
    - year
    - images
    fields: []
ftintitle:
    auto: yes
    drop: no
    format: feat. {0}
pathfields: {}
album_fields: {}
discogs:
    apikey: REDACTED
    apisecret: REDACTED
    tokenfile: discogs_token.json
    source_weight: 0.5
    user_token: REDACTED

beetbox / beets

zero: Removing images despite whitelisting images #3532

Problem

Workaround

Setup