Understand the failure.
Verify the repair.
Small, reproducible software failures. The broken implementation, the fix that didn’t work, and the one that passed—preserved together.
Explore the cases ↓How results are verified ↗WHAT THE ARCHIVE CONTAINS
100840 executable cases. 20168 are open.
Every case records the implementation that fails, the fix that did not work, and the repair that passed its checks—with recorded outputs and source hashes. This release adds 100840 cases across 20168 failure mechanisms and 254 domains.
The open tier gives you the failure and the unsuccessful fix for one case in every mechanism. The remaining 80672 cases, 5 variants per mechanism, are member-only: the verified repair, its recorded checks, and the full fixture suite are held in the member archive. Read the methodology ↗
A RECORD OF WHAT WENT WRONG
Browse the archive / 100840
Interval quality and number naming: compound octave reference counted every eight numbers · case 01
Double-octave compounds such as C4 to C6 lose one octave of reference span and return None.
Interval quality and number naming: compound octave reference counted every eight numbers · case 02
Double-octave compounds such as C4 to C6 lose one octave of reference span and return None.
Interval quality and number naming: compound octave reference counted every eight numbers · case 03
Double-octave compounds such as C4 to C6 lose one octave of reference span and return None.
Interval quality and number naming: compound octave reference counted every eight numbers · case 04
Double-octave compounds such as C4 to C6 lose one octave of reference span and return None.
Interval quality and number naming: compound octave reference counted every eight numbers · case 05
Double-octave compounds such as C4 to C6 lose one octave of reference span and return None.
Interval quality and number naming: fourth handled as an imperfect interval · case 01
The perfect fourth C4-F4 is named M4 and the augmented fourth C4-F#4 becomes an A4 only by accident of offsets.
Interval quality and number naming: fourth handled as an imperfect interval · case 02
The perfect fourth C4-F4 is named M4 and the augmented fourth C4-F#4 becomes an A4 only by accident of offsets.
Interval quality and number naming: fourth handled as an imperfect interval · case 03
The perfect fourth C4-F4 is named M4 and the augmented fourth C4-F#4 becomes an A4 only by accident of offsets.
Interval quality and number naming: fourth handled as an imperfect interval · case 04
The perfect fourth C4-F4 is named M4 and the augmented fourth C4-F#4 becomes an A4 only by accident of offsets.
Interval quality and number naming: fourth handled as an imperfect interval · case 05
The perfect fourth C4-F4 is named M4 and the augmented fourth C4-F#4 becomes an A4 only by accident of offsets.
Interval quality and number naming: descent judged by sound instead of letters · case 01
B#3 to Cb4 (letters ascend, pitch descends) is rejected, while C4 to B#3 slips through and produces a bogus label.
Interval quality and number naming: descent judged by sound instead of letters · case 02
B#3 to Cb4 (letters ascend, pitch descends) is rejected, while C4 to B#3 slips through and produces a bogus label.
Interval quality and number naming: descent judged by sound instead of letters · case 03
B#3 to Cb4 (letters ascend, pitch descends) is rejected, while C4 to B#3 slips through and produces a bogus label.
Interval quality and number naming: descent judged by sound instead of letters · case 04
B#3 to Cb4 (letters ascend, pitch descends) is rejected, while C4 to B#3 slips through and produces a bogus label.
Interval quality and number naming: descent judged by sound instead of letters · case 05
B#3 to Cb4 (letters ascend, pitch descends) is rejected, while C4 to B#3 slips through and produces a bogus label.
Spelled transposition by named interval: letter moved by the full generic number · case 01
A major third up from C is spelled on F (Fb4) instead of E4, because the letter advances one step too far.
Spelled transposition by named interval: letter moved by the full generic number · case 02
A major third up from C is spelled on F (Fb4) instead of E4, because the letter advances one step too far.
Spelled transposition by named interval: letter moved by the full generic number · case 03
A major third up from C is spelled on F (Fb4) instead of E4, because the letter advances one step too far.
Spelled transposition by named interval: letter moved by the full generic number · case 04
A major third up from C is spelled on F (Fb4) instead of E4, because the letter advances one step too far.
Spelled transposition by named interval: letter moved by the full generic number · case 05
A major third up from C is spelled on F (Fb4) instead of E4, because the letter advances one step too far.
Spelled transposition by named interval: octave does not carry across the B-C letter boundary · case 01
B3 up a minor second returns None instead of C4, because the octave never carries past the letter B.
Spelled transposition by named interval: octave does not carry across the B-C letter boundary · case 02
B3 up a minor second returns None instead of C4, because the octave never carries past the letter B.
Spelled transposition by named interval: octave does not carry across the B-C letter boundary · case 03
B3 up a minor second returns None instead of C4, because the octave never carries past the letter B.
Spelled transposition by named interval: octave does not carry across the B-C letter boundary · case 04
B3 up a minor second returns None instead of C4, because the octave never carries past the letter B.
Spelled transposition by named interval: octave does not carry across the B-C letter boundary · case 05
B3 up a minor second returns None instead of C4, because the octave never carries past the letter B.
Spelled transposition by named interval: downward pitch moved upward · case 01
Downward transpositions move the letter down but the pitch up, producing None or wild accidentals (C4 down M3 fails).
Spelled transposition by named interval: downward pitch moved upward · case 02
Downward transpositions move the letter down but the pitch up, producing None or wild accidentals (C4 down M3 fails).
Spelled transposition by named interval: downward pitch moved upward · case 03
Downward transpositions move the letter down but the pitch up, producing None or wild accidentals (C4 down M3 fails).
Spelled transposition by named interval: downward pitch moved upward · case 04
Downward transpositions move the letter down but the pitch up, producing None or wild accidentals (C4 down M3 fails).
Spelled transposition by named interval: downward pitch moved upward · case 05
Downward transpositions move the letter down but the pitch up, producing None or wild accidentals (C4 down M3 fails).
Spelled transposition by named interval: diminished imperfect interval equals minor · case 01
C4 up a diminished seventh returns Bb4 instead of Bbb4; diminished thirds and sixths collapse onto minor.
Spelled transposition by named interval: diminished imperfect interval equals minor · case 02
C4 up a diminished seventh returns Bb4 instead of Bbb4; diminished thirds and sixths collapse onto minor.
Spelled transposition by named interval: diminished imperfect interval equals minor · case 03
C4 up a diminished seventh returns Bb4 instead of Bbb4; diminished thirds and sixths collapse onto minor.
Spelled transposition by named interval: diminished imperfect interval equals minor · case 04
C4 up a diminished seventh returns Bb4 instead of Bbb4; diminished thirds and sixths collapse onto minor.
Spelled transposition by named interval: diminished imperfect interval equals minor · case 05
C4 up a diminished seventh returns Bb4 instead of Bbb4; diminished thirds and sixths collapse onto minor.
Spelled transposition by named interval: double accidentals rejected · case 01
Legitimate results like Bbb4 or D##5 are rejected even though two accidentals are within contract.
Spelled transposition by named interval: double accidentals rejected · case 02
Legitimate results like Bbb4 or D##5 are rejected even though two accidentals are within contract.
Spelled transposition by named interval: double accidentals rejected · case 03
Legitimate results like Bbb4 or D##5 are rejected even though two accidentals are within contract.
Spelled transposition by named interval: double accidentals rejected · case 04
Legitimate results like Bbb4 or D##5 are rejected even though two accidentals are within contract.
Spelled transposition by named interval: double accidentals rejected · case 05
Legitimate results like Bbb4 or D##5 are rejected even though two accidentals are within contract.
Enharmonic respelling on a requested letter: B sharp octave never searched · case 01
Respelling C4 on B returns None because the octave holding B#3 is outside the search window.
Enharmonic respelling on a requested letter: B sharp octave never searched · case 02
Respelling C4 on B returns None because the octave holding B#3 is outside the search window.
Enharmonic respelling on a requested letter: B sharp octave never searched · case 03
Respelling C4 on B returns None because the octave holding B#3 is outside the search window.
Enharmonic respelling on a requested letter: B sharp octave never searched · case 04
Respelling C4 on B returns None because the octave holding B#3 is outside the search window.
Enharmonic respelling on a requested letter: B sharp octave never searched · case 05
Respelling C4 on B returns None because the octave holding B#3 is outside the search window.
Enharmonic respelling on a requested letter: double accidentals excluded from respelling · case 01
G4 cannot be respelled as Abb4 and G4 on F returns None instead of Fx4.
Enharmonic respelling on a requested letter: double accidentals excluded from respelling · case 02
G4 cannot be respelled as Abb4 and G4 on F returns None instead of Fx4.
Enharmonic respelling on a requested letter: double accidentals excluded from respelling · case 03
G4 cannot be respelled as Abb4 and G4 on F returns None instead of Fx4.
Enharmonic respelling on a requested letter: double accidentals excluded from respelling · case 04
G4 cannot be respelled as Abb4 and G4 on F returns None instead of Fx4.
Enharmonic respelling on a requested letter: double accidentals excluded from respelling · case 05
G4 cannot be respelled as Abb4 and G4 on F returns None instead of Fx4.
Enharmonic respelling on a requested letter: respelled note keeps the sounding octave number · case 01
C4 respelled on B is printed B#4 and B3 on C is printed Cb3, an octave off in both cases.
Enharmonic respelling on a requested letter: respelled note keeps the sounding octave number · case 02
C4 respelled on B is printed B#4 and B3 on C is printed Cb3, an octave off in both cases.
Enharmonic respelling on a requested letter: respelled note keeps the sounding octave number · case 03
C4 respelled on B is printed B#4 and B3 on C is printed Cb3, an octave off in both cases.
Enharmonic respelling on a requested letter: respelled note keeps the sounding octave number · case 04
C4 respelled on B is printed B#4 and B3 on C is printed Cb3, an octave off in both cases.
Enharmonic respelling on a requested letter: respelled note keeps the sounding octave number · case 05
C4 respelled on B is printed B#4 and B3 on C is printed Cb3, an octave off in both cases.
Enharmonic respelling on a requested letter: alteration measured from pitch to letter · case 01
C#4 respelled on D prints D#4 instead of Db4: every accidental points the wrong way.
Enharmonic respelling on a requested letter: alteration measured from pitch to letter · case 02
C#4 respelled on D prints D#4 instead of Db4: every accidental points the wrong way.
Enharmonic respelling on a requested letter: alteration measured from pitch to letter · case 03
C#4 respelled on D prints D#4 instead of Db4: every accidental points the wrong way.
Enharmonic respelling on a requested letter: alteration measured from pitch to letter · case 04
C#4 respelled on D prints D#4 instead of Db4: every accidental points the wrong way.
Enharmonic respelling on a requested letter: alteration measured from pitch to letter · case 05
C#4 respelled on D prints D#4 instead of Db4: every accidental points the wrong way.
Key signature size for a named tonic: signature folded through pitch class · case 01
Gb major reports six sharps and C# major reports one sharp: enharmonic keys collapse onto one pitch class.
Key signature size for a named tonic: signature folded through pitch class · case 02
Gb major reports six sharps and C# major reports one sharp: enharmonic keys collapse onto one pitch class.
Key signature size for a named tonic: signature folded through pitch class · case 03
Gb major reports six sharps and C# major reports one sharp: enharmonic keys collapse onto one pitch class.
Key signature size for a named tonic: signature folded through pitch class · case 04
Gb major reports six sharps and C# major reports one sharp: enharmonic keys collapse onto one pitch class.
Key signature size for a named tonic: signature folded through pitch class · case 05
Gb major reports six sharps and C# major reports one sharp: enharmonic keys collapse onto one pitch class.
Key signature size for a named tonic: minor key shifted sharpward · case 01
A minor reports three sharps and D minor two sharps instead of zero and one flat.
Key signature size for a named tonic: minor key shifted sharpward · case 02
A minor reports three sharps and D minor two sharps instead of zero and one flat.
Key signature size for a named tonic: minor key shifted sharpward · case 03
A minor reports three sharps and D minor two sharps instead of zero and one flat.
Key signature size for a named tonic: minor key shifted sharpward · case 04
A minor reports three sharps and D minor two sharps instead of zero and one flat.
Key signature size for a named tonic: minor key shifted sharpward · case 05
A minor reports three sharps and D minor two sharps instead of zero and one flat.
Key signature size for a named tonic: flat side range not enforced · case 01
Fb major and Db minor are reported as eight flats instead of being rejected.
Key signature size for a named tonic: flat side range not enforced · case 02
Fb major and Db minor are reported as eight flats instead of being rejected.
Key signature size for a named tonic: flat side range not enforced · case 03
Fb major and Db minor are reported as eight flats instead of being rejected.
Key signature size for a named tonic: flat side range not enforced · case 04
Fb major and Db minor are reported as eight flats instead of being rejected.
Key signature size for a named tonic: flat side range not enforced · case 05
Fb major and Db minor are reported as eight flats instead of being rejected.
Key signature size for a named tonic: unknown mode treated as major · case 01
A dorian or capitalised Major request returns a major signature instead of None.
Key signature size for a named tonic: unknown mode treated as major · case 02
A dorian or capitalised Major request returns a major signature instead of None.
Key signature size for a named tonic: unknown mode treated as major · case 03
A dorian or capitalised Major request returns a major signature instead of None.
Key signature size for a named tonic: unknown mode treated as major · case 04
A dorian or capitalised Major request returns a major signature instead of None.
Key signature size for a named tonic: unknown mode treated as major · case 05
A dorian or capitalised Major request returns a major signature instead of None.
Key signature and measure accidental resolution: measure accidentals leak across barlines · case 01
A sharp written in one measure still raises the same note after the barline, so F4 after | stays F#4 even in C major.
Key signature and measure accidental resolution: measure accidentals leak across barlines · case 02
A sharp written in one measure still raises the same note after the barline, so F4 after | stays F#4 even in C major.
Key signature and measure accidental resolution: measure accidentals leak across barlines · case 03
A sharp written in one measure still raises the same note after the barline, so F4 after | stays F#4 even in C major.
Key signature and measure accidental resolution: measure accidentals leak across barlines · case 04
A sharp written in one measure still raises the same note after the barline, so F4 after | stays F#4 even in C major.
Key signature and measure accidental resolution: measure accidentals leak across barlines · case 05
A sharp written in one measure still raises the same note after the barline, so F4 after | stays F#4 even in C major.
Key signature and measure accidental resolution: accidental applies to every octave of the letter · case 01
C#4 followed by C5 in the same measure plays C#5 although the accidental applies only to octave 4.
Key signature and measure accidental resolution: accidental applies to every octave of the letter · case 02
C#4 followed by C5 in the same measure plays C#5 although the accidental applies only to octave 4.
Key signature and measure accidental resolution: accidental applies to every octave of the letter · case 03
C#4 followed by C5 in the same measure plays C#5 although the accidental applies only to octave 4.
Key signature and measure accidental resolution: accidental applies to every octave of the letter · case 04
C#4 followed by C5 in the same measure plays C#5 although the accidental applies only to octave 4.
Key signature and measure accidental resolution: accidental applies to every octave of the letter · case 05
C#4 followed by C5 in the same measure plays C#5 although the accidental applies only to octave 4.
Key signature and measure accidental resolution: natural sign falls back to the key signature · case 01
In G major, F4 after an explicit natural plays F#4 again because the natural mark (zero) is treated as absent.
Key signature and measure accidental resolution: natural sign falls back to the key signature · case 02
In G major, F4 after an explicit natural plays F#4 again because the natural mark (zero) is treated as absent.
Key signature and measure accidental resolution: natural sign falls back to the key signature · case 03
In G major, F4 after an explicit natural plays F#4 again because the natural mark (zero) is treated as absent.
Key signature and measure accidental resolution: natural sign falls back to the key signature · case 04
In G major, F4 after an explicit natural plays F#4 again because the natural mark (zero) is treated as absent.
Key signature and measure accidental resolution: natural sign falls back to the key signature · case 05
In G major, F4 after an explicit natural plays F#4 again because the natural mark (zero) is treated as absent.
Key signature and measure accidental resolution: flat signature built in sharp order · case 01
In F major the note F4 is flattened instead of B4; every flat key signature alters the wrong letters.
Key signature and measure accidental resolution: flat signature built in sharp order · case 02
In F major the note F4 is flattened instead of B4; every flat key signature alters the wrong letters.
Key signature and measure accidental resolution: flat signature built in sharp order · case 03
In F major the note F4 is flattened instead of B4; every flat key signature alters the wrong letters.
Key signature and measure accidental resolution: flat signature built in sharp order · case 04
In F major the note F4 is flattened instead of B4; every flat key signature alters the wrong letters.
Key signature and measure accidental resolution: flat signature built in sharp order · case 05
In F major the note F4 is flattened instead of B4; every flat key signature alters the wrong letters.
INSPECTABLE BY DESIGN
Every result has a runnable source.
Runnable implementations with recorded outputs, source hashes, and explicit contracts. Related variants share a failure mechanism and belong together in evaluation splits.
Read the methodology ↗