Fix roman.RomanNumeral Key cache colliding across modes#1906
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The _keyCache in roman.py was keyed by Key.tonicPitchNameWithCase, which
only encodes major (upper case) vs minor (lower case). Any other mode
(lydian, dorian, etc.) falls back to the upper-case tonic, so a C lydian
Key was cached under 'C' and collided with C major: after creating a
RomanNumeral in C lydian, a later RomanNumeral('I', 'C') returned the
cached lydian Key instead of C major.
Add a _keyCacheKey() helper used at both cache-store sites: major/minor
keep the case-only form so fast string lookups still hit, and any other
mode is qualified with its mode name (e.g. 'C lydian') so it cannot be
returned for a C major request. Add deterministic regression tests that
clear the cache and check both orderings and the resulting cache keys.
AI-assisted (Claude)
|
coverage: 93.049% (+0.003%) from 93.046% — fix-roman-key-cache-mode into master |
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Author
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Bug since at least 2015. Maybe older |
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Creating a
RomanNumeralin a non-major/minor mode (like Lydian or Dorian) poisons the cache for the major key (Lydian) or minor (Dorian, Phyrgian, etc.) on the same tonic.After creating
RomanNumeral('I', key.Key('C', 'lydian')), a subsequentRomanNumeral('I', 'C')returns a C lydian key instead of C major.Cause
roman.py's_keyCachewas keyed byKey.tonicPitchNameWithCase, which only distinguishes major (upper case) from minor (lower case). Every other mode falls back to the upper-case tonic, soC lydianwas stored under'C'and collided withC major.Fix
Add a
_keyCacheKey()helper used at both cache-store sites:'C','c') so existing fast string lookups still hit.'C lydian') so it can never be returned for aC majorrequest.AI-assisted (Claude)