Log Message:
py-music21: update to 9.1.0

Music21 v9 (June 2023) is the latest release of music21, a toolkit for \ 
computational music research.

Version 9 contains about 600 new commits and features from the version 8 release \ 
from September 2022. It is the latest and best release in the industry standard \ 
toolkit for doing music research and composition ("traditional" \ 
computation and AI/ML) with musical scores.

As a new Version X release, music21 gains a lot of its power with a few \ 
non-backwards compatible changes that make the system easier to use, faster, and \ 
more up to date. People using music21 in existing environments should read the \ 
change logs to make sure their systems work with it before upgrading.

A big change in music21 is that v9 is compatible with Python 3.10 and 3.11 only. \ 
The version 9 release will be updated to be compatible with at least Python 3.12 \ 
when it is released. Users on Python 3.8 and 3.9 should stick with v8 and those \ 
on older versions should look at the README to see what version will be \ 
installed for their systems.

Two weeks from the release of version 9 (July 1, 2023), Michael Asato Cuthbert, \ 
the lead developer of music21 will take a 6-12-month sabbatical from monitoring \ 
the mailing list, answering questions/issues, and merging PRs in order to focus \ 
on what he does best and what is best for the community: developing core parts \ 
of the system and documenting what already exists. Working with the user \ 
community has been amazing, but given that he only has about 10-15 hours per \ 
week to devote to the project, it often means deviating from efforts that help a \ 
large number of people to instead work through PRs and issues that are important \ 
to a smaller community. This news will probably not be welcomed by some, but the \ 
results should be better for the larger community.
What's Changed

    Music21 v9 is for Python 3.10 and 3.11 only and uses tools and speedups only \ 
available to those versions. Music21 drops its prior policy of supporting \ 
previous 3 versions and now supports the latest 2 versions only (to improve \ 
developer experience).
    Notebook/Jupyter: All pages are now shown on .show(). Compatible with \ 
Jupyter 7.0beta and JupyterLab. MIDI improvements (@mscuthbert in #1592)
    Added to corpus: (1) Queen Liliuokalani’s Aloha Oe, (2) J.R. Johnson’s \ 
Lift Every Voice And Sing (3) Vincente Lusitano’s madrigal Allor che Ignuda \ 
– part of a larger project to make the music21 corpus more representative.
    Lots more typing! Use music21 in a modern IDE to see it. Uses Python 3.10 \ 
TypeGuards. Add common.classTools.holdsType([‘a’, ‘b’], str) which \ 
asserts that everything in a collection has the same type. (@mscuthbert in \ 
#1447). converter and corpus are fully typed.
    Docs! Documentation of equality explained better. braille, corpus, converter \ 
much improved. (1) Much better aesthetics and utility @mscuthbert in #1455 and \ 
#1452). (2) Add “developerReference/startingOver” – mistakes made in \ 
designing music21 that are too late to fix, but the next generation of software \ 
should not emulate. (3) add docs about abcFormat support (@mscuthbert in #1484). \ 
(4) coreInsert (@mscuthbert in #1549). (5) layout (@mscuthbert in #1554). (6) \ 
clercqTemperley (RS100 dataset) format (#1558)
    RomanText and related formats: (1) Repeats in RT and TSV are improved \ 
(@malcolmsailor in #1434, #1435, #1503) (2) anacrusis support (@mscuthbert in \ 
#1532) (3) measure numbers on ClercqTemperley (@mscuthbert in #1558)
    harmony: (1) RomanNumerals and ChordSymbols with front accidentals (flat II, \ 
sharp IV, etc.) now take their 7ths, 9ths, etc. from the underlying keys \ 
(@mscuthbert w/ thanks to @malcolmsailor in #1439), (2) RomanNumeral’s \ 
writeAsChord works properly (@mscuthbert in #1445)
    and (3) transpose properly (@malcolmsailor in #1414). (4) \ 
roman.RomanNumeral(2, ‘C’) will now give d-minor, not d-major \ 
(@jacobtylerwalls in #1481), (5) preferSecondaryDominants implements V/x \ 
(@MarkGotham in #796).
    MusicXML improvements: (1) TempoText is exported (@gregchapman-dev in #1437)
    (2) harmony/numeral figures are MusicXML 4.0 compatible (@mscuthbert in \ 
#1445) (3) Preserve multiple fingerings on chords in musicxml import \ 
(@jacobtylerwalls in #1475) (4) Translate "implicit" attribute of \ 
MusicXML measures (@jacobtylerwalls in #1493) (5) Synchronize Measure IDs on \ 
Musicxml out (@rigaux in #1490) (6) MusicXML sound tag finds metronome marks \ 
(@TimFelixBeyer in #1579) (7) Add MusicXML security warning (@mscuthbert in \ 
#1584)
    Speed/Performance improvements on (1) deepcopy (@mscuthbert in #1464) (2) \ 
ABC (@mscuthbert in #1461) (3) LanguageDetector (@mscuthbert in #1456) (4) \ 
quantize() (@TimFelixBeyer in #1594) (5) use deques instead of pop(0) #1466, (6) \ 
searching/MetadataBundles cache in tests (@mscuthbert in #1511)
    (7) findGaps() on gapless streams (@jacobtylerwalls in #1515) (8) \ 
ChordSymbols (@jacobtylerwalls in #1527)
    Braille – add segment.BrailleElementGrouping. Good amount of refactoring. \ 
(@mscuthbert in #1495)
    Converter/Corpus: converter.toData – like .write or .show but gives the \ 
raw data as a string or byte by @mscuthbert in #1451
    Frozen/Immutable objects can be created now; this will allow for creating, \ 
for instance, one default 4/4 meter that cannot be changed but used as a default \ 
in many places. common.FrozenObject and duration.FrozenDuration (@mscuthbert in \ 
#1460)
    New subConverters register above default subConverters, so it is now \ 
possible to develop a subConverter like Greg’s converter21 project that \ 
handles a format music21 supports but do it differently or better. (@mscuthbert \ 
in #1520)
    Ornaments/Expressions (all by @gregchapman-dev) – (1) ornament accidentals \ 
have a great new system and are aware of their measure and key context (#1545) \ 
(2) Mordents get placement like Turn and Trill (#1516) (3) Support for delayed \ 
turns (#1533)
    Spanners: (1) Spanner.fill() – say you’ve set a slur to just include the \ 
first and last notes. .fill() will find all the intermediate notes. \ 
(@gregchapman-dev in #1486) (2) spanner.SpannerAnchor class allows a spanner to \ 
start and stop at a point where there is no other Music21Object at the offset \ 
(like a whole note crescendo that begins on beat 2 and ends on beat 3) \ 
(@gregchapman-dev in #1479). (3) Guitar: Hammer-on and Pull-off as Spanners \ 
(@louisbigo in #1142)
    Streams – (1) new module stream.tools and stream.tools.removeDuplicates \ 
(e.g. keys, clefs, by @MarkGotham in #1454) . (2) \ 
stream.makeNotation.saveAccidentalDisplayStatus() context manager for restoring \ 
pitches’ accidentalDisplayStatus after a manipulation (like transposition by \ 
octave) @gregchapman-dev. (3) stream.makeNotation.makeOrnamentalAccidentals \ 
(#1545)
    Percussion: (1) Implement useful PercussionChord.pitches property \ 
(@jacobtylerwalls in #1547), (2) Ignore Unpitched objects in key analysis \ 
(@jacobtylerwalls in #1543, (3) Search support (@mscuthbert in #1597)
    MIDI: (1) Minimize gaps produced by quantization algorithm (@jacobtylerwalls \ 
in #1540) (2) fix jupyter/colab MIDI (@mscuthbert in #1565) (3) Increase default \ 
MIDI ticksPerQuarter for higher accuracy of tuplets (@TimFelixBeyer in #1577)
    ABC: set version from I:abc-version information (@mscuthbert in #1589)
    pitch module gets: isValidAccidentalName, standardizeAccidentalName.

Bug fixes

    Ottava transposition bugs (in m21 and in musicxml output) (@gregchapman-dev \ 
in #1486)
    diminished and half-diminished 11th chord types were incorrect \ 
(@jacobtylerwalls in #1497)
    Avoid creating duplicative ChordStepModifications (@jacobtylerwalls in #1509)
    Zero quarterLengths will not be represented as Fraction(0, 1)
    MIDI: (1) Don't set status byte on Meta Message (@TimFelixBeyer in #1575) \ 
(2) unknown meta message still parses (@TimFelixBeyer in #1573)
    Fix stripTies when accidentals are natural & none (@TimFelixBeyer in #1556)
    Scores could previously change after .write()(@TimFelixBeyer in #1560)
    requests should have been in the minimum requirements (@jacobtylerwalls in #1568)
    Prevent doubly-flatted sevenths in chord symbols (@jacobtylerwalls in #1572)

Incompatible Changes not mentioned above:

    Equality: == or __eq__ comparison on many objects has changed. – it is now \ 
based on a class hierarchy where the object needs to be equal in all of its \ 
super-classes (@mscuthbert in #1466 and #1459).
    For time signatures: (@MarkGotham in #1457). For ChordStepModification \ 
(@jacobtylerwalls in #1482). An exception is made for RomanNumerals which do not \ 
need to have pitches in the same octave (like their chord.Chord superclass \ 
requires)
    schumann folder is moved to schumann_robert to match (equally amazing) \ 
schumann_clara.
    subConverter is consistently spelled with capital C in all contexts. Before \ 
it was a mismash of capital C and lowercase C. (in #1592)
    Full Measure Rests taken into account Finale usage of the measure=”yes” \ 
tag on pickups (@mscuthbert in #1595)
    All Music21Objects must be hashable and default instantiate (@mscuthbert in \ 
#1467)
    Duration, volume, and StreamStatus all keep string references to clients \ 
(major change if you were playing with _client private variables. Only a public \ 
change if you were counting on garbage collection to run more often)
    contextSites that are derived fixes a bug.
    Developers using the private _deepcopySubclassable should know that \ 
“removeFromIgnore” has been removed for performance reasons.
    Spanner.prePostObjectSpanners is renamed “relatedSpanners()”
    A number of cases where an attribute which is usually a string started with \ 
None now start with ‘’ instead (typing improvement)
    Refactors to ipython21 and the IPython (now Jupyter), MIDI, MusicXML \ 
subconverters in #1592.

Removals

    Music21Exception subclasses not used in the system are removed. Reduce 172 \ 
Exceptions to 154 (@mscuthbert in #1465)
    musicxml.xmlToM21.textNotNone – use new strippedText() and check for False.
    Already marked for deprecation and removed: common.cleanupFloat() (use \ 
opFrac), common.euclidGCD (use math.gcd), Metadata.setWorkId (use md.uniqueName \ 
= value), VoiceLeadingQuartet.color() (assign colors to individual notes with \ 
.style.color), (#1440)

Deprecations

    Spanner.numberRange replaces Spanner.getNumberList() — they do the same \ 
thing. (#1447)
    romanText.clercqTemperley – toScore() – call toPart() instead since that \ 
is what it does.
    scale.next() – use scale.nextPitch() instead – since it shadows \ 
Music21Object.next()

New Contributors

    @sararocks made her first contribution in #1472
    @rigaux made their first contribution in #1490
    @TimFelixBeyer made his first contribution in #1560