missing accidental after clef change

[Keith OHara]

Dear bug squad,
  I am rephrasing a report that got lost in a long-ish thread
<http://lists.gnu.org/archive/html/bug-lilypond/2010-12/msg00403.html>
discussing whether it was really a bug.  The thread eventually made clear: it 
is.

% When there is a clef change within a measure, we want cancellation 
accidentals to
% be printed, if they would be printed for the same pitches without the clef 
change.

\version "2.12.3"  % 2.13.43 behaves the same
\relative c' {
   \key d \major
   \clef bass
   c4
   \clef treble
   c4
   \clef bass
   cis2 } % the sharp symbol is missing from the output

%  Workarounds: #(set-accidental-style 'piano)
%  or inspect the output near clef changes
%  and force accidentals, cis!2, when required


The regression test accidental-clef-change.ly demonstrates that accidentals 
moving
away from the key signature are repeated after a mid-measure clef change.  This 
is
helpful, but might cause the problem above as a side-effect.

I would consider adding the extra accidentals in accidental-clef-change.ly to be
not as important as printing the within-measure cancellation accidentals.
The best behavior would be to have both: print accidental symbols if they would 
print
in the chosen accidental-style either in absence of the clef change, or with the
clef change treated as a reset to the key signature.

missingAccidental.png
Description: PNG image