Re: Wrong type in part-combiner.scm

[David Kastrup]

Pierre-Luc Gauthier <p.luc.gauthier@gmail.com> writes:

> Hi there,
>
> When I compile :
>
> test = {}
> \addQuote "test" \test
>
> I get :
>
> GNU LilyPond 2.21.7
> Processing `test.ly'
> Parsing...
> Interpreting music.../usr/share/lilypond/2.21.7/scm/part-combiner.scm:956:30:
> In procedure car in expression (car current-tail):
> /usr/share/lilypond/2.21.7/scm/part-combiner.scm:956:30: Wrong type
> (expecting pair): #f
>
> Can anyone corroborate ?

That's interesting.  With my current version in /usr/local/bin I get

-*- mode: compilation; default-directory: "/tmp/" -*-
Compilation started at Tue Sep 22 14:35:27

lilypond /tmp/ba.ly
GNU LilyPond 2.21.0
Processing `/tmp/ba.ly'
Parsing...
Interpreting music...
warning: no music found in score
/tmp/ba.ly:2:18: warning: quoted music `test' is empty
\addQuote "test" 
                 \test
/tmp/ba.ly:1: warning: no \version statement found, please add

\version "2.21.0"

for future compatibility
Success: compilation successfully completed

Compilation finished at Tue Sep 22 14:35:28

With current master, I instead get

-*- mode: compilation; default-directory: "/tmp/" -*-
Compilation started at Tue Sep 22 14:35:51

/usr/local/tmp/lilypond/out/bin/lilypond ba.ly
GNU LilyPond 2.21.7
Processing `ba.ly'
Parsing...
Interpreting 
music.../usr/local/tmp/lilypond/out/share/lilypond/current/scm/part-combiner.scm:956:30:
 In procedure car in expression (car current-tail):
/usr/local/tmp/lilypond/out/share/lilypond/current/scm/part-combiner.scm:956:30:
 Wrong type (expecting pair): #f

Compilation exited abnormally with code 1 at Tue Sep 22 14:35:52

The code bombing out is clearly wrong:

    (if (null? quote-contents)
        (let find-non-empty ((current-tail (member raw-voice context-list)))
          ;; if voice has contents, use them, otherwise check next ctx
          (cond ((null? current-tail) #f)
                ((and (pair? (car current-tail))
                      (pair? (cdar current-tail)))
                 (set! quote-contents (cdar current-tail)))
                (else (find-non-empty (cdr current-tail))))))

because (null? current-tail) can never be true (it's either #f or a
pair).  This should be (not current-tail) instead.

However, this particular buggy code has not changed for a long long
time, so a more recent change must have affected context-list which
previous to that change apparently always contained raw-voice somewhere,
or at least in the case you now posted.

-- 
David Kastrup