fix(autotag): "featuring" pattern in string_dist matches mid-word "ft"

[chuenchen309]

Bug

SD_PATTERNS in beets/autotag/distance.py has this entry:

(r"[\[\(]?(featuring|feat|ft)[\. :].+", 0.1),

The ft alternative has no word boundary before it, so it matches ft embedded inside any ordinary word followed by a space/period/colon — draft, left, gift, craft, soft, swift, etc. — and treats everything after the match as a low-weight "featuring artist" suffix (weight 0.1), effectively deleting it from the comparison.

from beets.autotag.distance import string_dist
string_dist("Draft Beer", "Draft Whiskey")   # 0.05  (near-identical!)
string_dist("Left Field", "Left Symphony")   # 0.067
string_dist("Gift Ideas", "Gift Cards")      # 0.044

Confirmed through the actual matching pipeline (track_distance) too: "Draft Beer" vs. "Draft Whiskey" scores almost as close as an exact match, while a genuinely unrelated title correctly scores much higher. string_dist/add_string backs nearly every fuzzy field comparison used during beet import (title, artist, album, label, catalognum, ...), so this silently degrades match quality for any title/artist containing one of these words.

Fix

Add a word boundary before the alternation:

(r"[\[\(]?\b(featuring|feat|ft)[\. :].+", 0.1),

Verified this doesn't regress the intended "real" cases ("Song feat. Artist", "[feat: Artist]", "(ft. Artist)" — all still match, since they're preceded by whitespace/bracket/string-start, which are real boundaries) while excluding all the false-positive mid-word cases above.

Testing

Added test_featuring_pattern_does_not_match_mid_word (parametrized over draft/left/gift/craft) to test/autotag/test_distance.py, asserting string_dist(...) > 0.3 for these pairs (previously ~0.04-0.07). Verified red on master (git stash the source fix — all 4 cases fail with the near-zero distances shown above), green after. Full test/autotag/test_distance.py (58 passed) and the broader test/autotag/ + test/util/ + test/autotag/test_match.py + test/test_importer.py suites (352 + 142 passed, no regressions) all pass. ruff check/ruff format --check/mypy clean.

Added a changelog entry per CONTRIBUTING.rst's reminder.

Duplicate-work check

Searched open PRs for distance.py/"featuring" — found #6681 (Source class refactor) also touches distance.py, but its diff doesn't touch SD_PATTERNS or this area at all. No overlap.

---

This PR was drafted with AI assistance (Claude); I independently reproduced the bug against the real, unmodified module (including through the full track_distance matching pipeline) and verified the fix. I reviewed the change and take responsibility for it.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.59%. Comparing base (2cf20aa) to head (f0bb497).
⚠️ Report is 29 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6843      +/-   ##
==========================================
- Coverage   75.60%   75.59%   -0.02%     
==========================================
  Files         163      163              
  Lines       21299    21299              
  Branches     3358     3358              
==========================================
- Hits        16103    16100       -3     
- Misses       4406     4408       +2     
- Partials      790      791       +1     

Files with missing lines	Coverage Δ
beets/autotag/distance.py	83.52% <ø> (ø)

... and 3 files with indirect coverage changes

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[chuenchen309]

Applied — added the trailing \b so the boundary is symmetric on both sides. Full test/autotag/test_distance.py still passes (58/58), including the mid-word regression cases and the existing featuring-suffix matches. Thanks for the review!

[snejus]

Thanks!