Handle legacy fields in modify and queries

[snejus]

Handle legacy singular field names in modify and queries

This PR centralises the mapping of legacy singular field names (e.g. genre, composer, lyricist, remixer, arranger) to their modern plural multi-valued equivalents (e.g. genres, composers, ...) and applies that rewrite in two places: the modify command and library field queries.

What changed

beets/util/deprecation.py — new source of truth

Two module-level dicts, ALBUM_LEGACY_TO_LIST_FIELD and ITEM_LEGACY_TO_LIST_FIELD, now live here. A new helper maybe_replace_legacy_field(field, is_album) wraps the lookup, emits a deprecation warning via the shared log, and returns the canonical field name.

beets/library/models.py — queries now handle legacy fields

field_query calls maybe_replace_legacy_field before resolving whether the field is fast or slow. This means queries like genre::rock or composer::bach are transparently rewritten and warn the user.

beets/ui/commands/modify.py — simplified using the shared helper

The inline legacy-field lookup and deprecate_for_user call inside modify_parse_args are replaced with a single call to maybe_replace_legacy_field. The is_album parameter is passed through from modify_func.

beets/autotag/hooks.py — LEGACY_TO_LIST_FIELD now references the shared dicts

AlbumInfo and TrackInfo no longer define their own inline mappings; they reference the canonical dicts from deprecation.py.

Impact

• Users who pass legacy field names in modify assignments or in query expressions now get a deprecation warning and correct behaviour, instead of silently operating on a non-existent field.
• The legacy mapping is defined once, removing the previous drift risk between hooks.py, modify.py, and any future call sites.
• Fixes 🐛6483.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.18%. Comparing base (4aaf58b) to head (724891f).
⚠️ Report is 3 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6494      +/-   ##
==========================================
+ Coverage   70.15%   70.18%   +0.02%     
==========================================
  Files         147      147              
  Lines       18662    18680      +18     
  Branches     3040     3042       +2     
==========================================
+ Hits        13093    13111      +18     
  Misses       4927     4927              
  Partials      642      642              

Files with missing lines	Coverage Δ
beets/autotag/hooks.py	98.85% <100.00%> (+<0.01%)	⬆️
beets/library/models.py	87.10% <100.00%> (+0.04%)	⬆️
beets/ui/commands/modify.py	93.93% <100.00%> (+0.18%)	⬆️
beets/util/deprecation.py	91.17% <100.00%> (+5.46%)	⬆️

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[Copilot]

Pull request overview

PR make beet modify accept old singular multi-value field names, then rewrite to new plural field names and warn user, so user no longer make wrong custom field by accident.

Changes:

• Add central legacy->plural list field maps in beets/util/deprecation.py
• Reuse those maps from autotag AlbumInfo / TrackInfo instead of inline maps
• Update modify_parse_args to rewrite legacy assignment keys + emit user-facing deprecation warning; add tests + docs

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
beets/util/deprecation.py	Add shared legacy singular → plural list-field mapping constants.
beets/autotag/hooks.py	Switch Info subclasses to use shared mapping constants.
beets/ui/commands/modify.py	Rewrite legacy assignment keys to plural fields + warn user.
test/ui/commands/test_modify.py	Update call sites for new arg + add rewrite/warn tests.
test/autotag/test_hooks.py	Stop using Info directly in legacy-field tests; use TrackInfo.
docs/reference/cli.rst	Document legacy singular field support in modify.
docs/changelog.rst	Add changelog entry for modify legacy-field rewrite behavior.

[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.