Returning *unspecified* from Scheme callback causes no caching
\version "2.23.6"
{
\override NoteHead.stencil =
#(lambda (grob)
(ly:message "Callback run"))
c'1
}
The above prints
Callback run
Callback run
Finding the ideal number of pages...
Fitting music on 1 page...
Drawing systems...
Callback run
Callback run
The principle of grob callbacks is that they will only be run once. The handling of the *unspecified*
value seems to defeat this.
Edited by Jean Abou Samra