Re: Issue 2030 in lilypond: 2.14.2, dynamic cast crash introduced in commit 6f6369c0

[lilypond]

Comment #2 on issue 2030 by address@hidden: 2.14.2, dynamic cast crash  
introduced in commit 6f6369c0
http://code.google.com/p/lilypond/issues/detail?id=2030

The bug as it's entered is bogus.  It turns out lilypond has an issue with  
the build system.  The incremental make is not reliable (another bug!).   
Only "make clean && make" can be relied upon.  With the correctly built  
lilypond this example doesn't cause a crash.  I simplified my example too  
much.  Here's the minimal lilypond file that crashes even correctly built  
lilypond:

\version "2.14.2"
\score {
  <<
    \new Staff = right { r4 \change Staff=left r8 b b b \change Staff=right  
s }
    \new Staff = left { r4 }
  >>
  \layout { }
}

And that's where the crash happens:

GNU LilyPond 2.14.2
Processing `bad.ly'
Parsing...
Interpreting music...
Program received signal SIGSEGV, Segmentation fault.
0x000000000052febc in Context::get_parent_context (this=0x0) at  
context.cc:688
688       return daddy_context_;
(gdb) where
#0  0x000000000052febc in Context::get_parent_context (this=0x0) at  
context.cc:688
#1  0x000000000054cd6f in Engraver_group::announce_grob (this=0xdcb970,  
info=...) at engraver-group.cc:73
#2  0x000000000054ce14 in Engraver_group::announce_grob (this=0xddb9b0,  
info=...) at engraver-group.cc:86
#3  0x000000000054f160 in Engraver::announce_grob (this=0xdc8890, inf=...)  
at engraver.cc:40
#4  0x00000000004b4ac9 in Auto_beam_engraver::create_beam (this=0xdc8890)  
at auto-beam-engraver.cc:225
#5  0x00000000004b4edc in Auto_beam_engraver::end_beam (this=0xdc8890) at  
auto-beam-engraver.cc:272
#6  0x00000000004b4304 in Auto_beam_engraver::process_music (this=0xdc8890)  
at auto-beam-engraver.cc:130
#7  0x0000000000743261 in Translator_method_binding::invoke (this=0xdca950)  
at ./include/translator-group.hh:46
#8  0x0000000000742b3b in Translator_group::precomputed_translator_foreach  
(this=0xddb9e0, idx=PROCESS_MUSIC)
    at translator-group.cc:325
#9  0x0000000000742706 in precomputed_recurse_over_translators (c=0xddab60,  
idx=PROCESS_MUSIC, dir=UP)
    at translator-group.cc:256
#10 0x00000000007426c8 in precomputed_recurse_over_translators (c=0xdc0170,  
idx=PROCESS_MUSIC, dir=UP)
    at translator-group.cc:252
#11 0x00000000007426c8 in precomputed_recurse_over_translators (c=0xc8dab0,  
idx=PROCESS_MUSIC, dir=UP)
    at translator-group.cc:252
#12 0x000000000068eb4f in Score_engraver::one_time_step (this=0xc8e600) at  
score-engraver.cc:151
#13 0x000000000068e725 in Score_engraver::one_time_step_callback  
(self=0xc8e600, ev=0x7fffef0b82c0)
    at score-engraver.cc:145
#14 0x00000000005bf2c2 in Listener::listen (this=0xc8f2e0,  
ev=0x7fffef0b82c0) at listener.cc:43
#15 0x0000000000539697 in Dispatcher::dispatch (this=0xc8d160,  
sev=0x7fffef0b82c0) at dispatcher.cc:150
#16 0x0000000000538ae8 in Dispatcher::broadcast (this=0xc8d160,  
ev=0xdf8ab0) at dispatcher.cc:173
#17 0x000000000052efd3 in Context::internal_send_stream_event  
(this=0xc8c998, type=0x7ffff10ad840, origin=0x0, props=
    0x7fffffff8fc0) at context.cc:461
#18 0x0000000000574a00 in Global_context::run_iterator_on_me  
(this=0xc8c910, iter=0xc8d660) at global-context.cc:170
#19 0x00000000005732b7 in ly_interpret_music_expression  
(mus=0x7fffef1ef8f0, ctx=0x7fffef12d490)
    at global-context-scheme.cc:119
#20 0x0000000000573885 in ly_run_translator (mus=0x7fffef1ef8f0,  
output_def=0x7fffef1486e0)
    at global-context-scheme.cc:147
#21 0x0000000000693f93 in Score::book_rendering (this=0xda6f30,  
layoutbook=0xda7a50, default_def=0xd5b730)
    at score.cc:157
#22 0x00000000004fa2ea in Book::process_score (this=0xda5ba0,  
s=0x7fffef148750, output_paper_book=0xda79e0, layout=
    0xd5b730) at book.cc:236
#23 0x00000000004fa65a in Book::process (this=0xda5ba0,  
default_paper=0xd59f50, default_layout=0xd5b730, parent_part=
    0x0) at book.cc:302
#24 0x00000000004fa1a5 in Book::process (this=0xda5ba0,  
default_paper=0xd59f50, default_layout=0xd5b730) at book.cc:207
#25 0x00000000004f7877 in ly_book_process (book_smob=0x7fffef168f30,  
default_paper=0x7fffef408170, default_layout=
    0x7fffef30b3b0, output=0x7ffff0e32ea0) at book-scheme.cc:76
#26 0x000000364ea4f576 in ceval (x=<optimized out>, env=0x7fffef168470) at  
eval.c:4382
#27 0x0000000000653b56 in internal_ly_parse_scm (ps=0x7fffffff9620) at  
parse-scm.cc:76
#28 0x0000000000653d6a in ly_parse_scm (s=
    0xc7d14d "(let ((book-handler (if  
(defined? 'default-toplevel-book-handler)\n", ' ' <repeats 25  
times>, "default-toplevel-book-handler\n", ' ' <repeats 25  
times>, "toplevel-book-handler)))\n   (cond ((pair? toplevel-boo"..., n=
    0x7fffffff9ab0, i=..., safe=false, parser=0xc7ae70) at parse-scm.cc:139
#29 0x000000000076363d in Lily_lexer::yylex (this=0xc7aef0) at lexer.ll:351
#30 0x00000000007771e5 in yylex (s=0x7fffffffc4d0, loc=0x7fffffffba40,  
v=0xc7ae70) at parser.yy:2790
#31 0x0000000000769a92 in yyparse (my_lily_parser=0xc7ae70) at  
out/parser.cc:2507
#32 0x000000000077628a in Lily_parser::do_yyparse (this=0xc7ae70) at  
parser.yy:2563
#33 0x00000000005b6ffa in Lily_parser::parse_file (this=0xc7ae70,  
init="init.ly", name="bad.ly", out_name="bad")
    at lily-parser.cc:121
#34 0x00000000005b2a65 in ly_parse_file (name=0x7ffff0e9ede0) at  
lily-parser-scheme.cc:123
#35 0x000000364ea4fda2 in ceval (x=<optimized out>, env=0x7fffec8b6740) at  
eval.c:4232
#36 0x000000364eaa4393 in scm_c_catch (tag=0x7ffff0eeabe0,  
body=0x364eaa4150 <scm_body_thunk>, body_data=
    0x7fffffffd990, handler=0x364eaa4140 <scm_handle_by_proc>,  
handler_data=0x7fffffffd988, pre_unwind_handler=0,
    pre_unwind_handler_data=0x7fffffffd980) at throw.c:203
#37 0x000000364eaa459e in scm_catch_with_pre_unwind_handler (key=<optimized  
out>, thunk=<optimized out>, handler=
    0x7fffec8b67d0, pre_unwind_handler=0x204) at throw.c:587
#38 0x000000364ea4f576 in ceval (x=<optimized out>, env=0x7fffec8b6890) at  
eval.c:4382
#39 0x000000364ea4f97c in ceval (x=0x7fffecc178c0, env=0x7fffec8b6940) at  
eval.c:3397
#40 0x00007fffefca5fc1 in scm_srfi1_for_each (proc=0x7fffec8b8f80,  
arg1=0x7fffecc86740, args=0x404) at srfi-1.c:1516
#41 0x000000364ea4ff9c in ceval (x=<optimized out>, env=0x7fffecc86c20) at  
eval.c:4367
#42 0x000000364ea4f97c in ceval (x=0x7fffecc16020, env=0x7fffecc86c20) at  
eval.c:3397
#43 0x000000364ea50ae3 in ceval (x=0x7fffecc86a70, env=0x7fffecc867f0) at  
eval.c:3648
#44 0x00000000005cbdb4 in main_with_guile () at main.cc:437
#45 0x000000364ea66f6f in invoke_main_func (body_data=0x7fffffffdff0) at  
init.c:367
#46 0x000000364ea3da9a in c_body (d=0x7fffffffdf90) at continuations.c:349
#47 0x000000364eaa4393 in scm_c_catch (tag=0x104, body=0x364ea3da90  
<c_body>, body_data=0x7fffffffdf90, handler=
    0x364ea3dab0 <c_handler>, handler_data=0x7fffffffdf90,  
pre_unwind_handler=
    0x364eaa49c0 <scm_handle_by_message_noexit>,  
pre_unwind_handler_data=0x0) at throw.c:203
#48 0x000000364ea3e027 in scm_i_with_continuation_barrier  
(body=0x364ea3da90 <c_body>, body_data=0x7fffffffdf90,
    handler=0x364ea3dab0 <c_handler>, handler_data=0x7fffffffdf90,  
pre_unwind_handler=<optimized out>,
    pre_unwind_handler_data=<optimized out>) at continuations.c:325
#49 0x000000364ea3e0c0 in scm_c_with_continuation_barrier (func=<optimized  
out>, data=<optimized out>)
    at continuations.c:367
#50 0x000000364eaa2844 in scm_i_with_guile_and_parent (func=0x364ea66f50  
<invoke_main_func>, data=0x7fffffffdff0,
    parent=<optimized out>) at threads.c:733
#51 0x000000364ea67025 in scm_boot_guile (argc=<optimized out>,  
argv=<optimized out>, main_func=<optimized out>,
    closure=<optimized out>) at init.c:350
#52 0x00000000005cd0c8 in main (argc=2, argv=0x7fffffffe158,  
envp=0x7fffffffe170) at main.cc:632
(gdb) up
#1  0x000000000054cd6f in Engraver_group::announce_grob (this=0xdcb970,  
info=...) at engraver-group.cc:73
73        Context *dad_con = context_->get_parent_context ();
(gdb) up
#2  0x000000000054ce14 in Engraver_group::announce_grob (this=0xddb9b0,  
info=...) at engraver-group.cc:86
86          dad_eng->announce_grob (info);
(gdb) p dad_eng->context_
$1 = (Context *) 0x0
(gdb) p dad_eng
$2 = (Engraver_group *) 0xdcb970