Re: Issue 4419: Engraving ends too early (issue 252970043 by address@hidden)

[dak]

Reviewers: Dan Eble,

Message:
On 2015/07/10 02:56:43, Dan Eble wrote:
> I haven't absorbed enough of the background knowledge on iteration to
say
> credibly that this looks good, although the C++ looks fine.

> Because this is a second try at fixing a problem, perhaps a regression
test
> should be written or expanded to cover the case that the first try did
not.

Well, I'd like such a test to also cover issue 2608 which is not yet on
countdown.  Making it part of _this_ issue would be a bad idea since
issue 2608 is a crash, and a regtest for a crash should not be committed
before the fix.

Description:
Issue 4419: Engraving ends too early

This is a followup on the solution for issue 2010 that was too eager
killing off unrelated iterators when an iterator in the vicinity of a
Lyric_combine_music_iterator died.

The salient point is to have Simultaneous_music_iterator::process_music
check for pending_moment () going from finite to infinite when
iterating, signifying the loss of an iterator defining an end point.

It happens to also fix issue 4339.


Also contains commit:

simplify Simultaneous_music_iterator::ok

Please review this at https://codereview.appspot.com/252970043/

Affected files (+12, -18 lines):
  M lily/simultaneous-music-iterator.cc


Index: lily/simultaneous-music-iterator.cc
diff --git a/lily/simultaneous-music-iterator.cc  
b/lily/simultaneous-music-iterator.cc
index  
74f2d6dc9abbb2b14f182bbeeab5db6368f26a60..e892776b61a39e6f4814eb350500ab706a45c4ee  
100644
--- a/lily/simultaneous-music-iterator.cc
+++ b/lily/simultaneous-music-iterator.cc
@@ -82,36 +82,33 @@ Simultaneous_music_iterator::construct_children ()
     }
 }

-// If there are non-run-always iterators and all of them die, take the
-// rest of them along.
+// If we have some iterators with definite next moment and no of them
+// remain after processing, we take the iterators with indefinite next
+// moment along.  That makes sure that no Lyric_combine_music_iterator
+// will outstay its welcome (issue 2010).
+
 void
 Simultaneous_music_iterator::process (Moment until)
 {
-  bool had_good = false;
-  bool had_bad = false;
   SCM *proc = &children_list_;
+  bool finite = !pending_moment ().main_part_.is_infinity ();
   while (scm_is_pair (*proc))
     {
       Music_iterator *i = unsmob<Music_iterator> (scm_car (*proc));
-      bool run_always = i->run_always ();
-      if (run_always || i->pending_moment () == until)
+      if (i->run_always () || i->pending_moment () == until)
         i->process (until);
       if (!i->ok ())
         {
-          if (!run_always)
-            had_bad = true;
           i->quit ();
           *proc = scm_cdr (*proc);
         }
       else
         {
-          if (!run_always)
-            had_good = true;
           proc = SCM_CDRLOC (*proc);
         }
     }
-  // If there were non-run-always iterators and all of them died, take
-  // the rest of the run-always iterators along with them.  They have
+  // If there were definite-ended iterators and all of them died, take
+  // the rest of the iterators along with them.  They have
   // likely lost their reference iterators.  Basing this on the actual
   // music contexts is not reliable since something like
   // \new Voice = blah {
@@ -121,7 +118,7 @@ Simultaneous_music_iterator::process (Moment until)
   // }
   // cannot wait for the death of context blah before ending the
   // simultaneous iterator.
-  if (had_bad && !had_good)
+  if (finite && pending_moment ().main_part_.is_infinity ())
     {
       for (SCM p = children_list_; scm_is_pair (p); p = scm_cdr (p))
         unsmob<Music_iterator> (scm_car (p))->quit ();
@@ -147,16 +144,13 @@ Simultaneous_music_iterator::pending_moment () const
 bool
 Simultaneous_music_iterator::ok () const
 {
-  bool run_always_ok = false;
   for (SCM s = children_list_; scm_is_pair (s); s = scm_cdr (s))
     {
       Music_iterator *it = unsmob<Music_iterator> (scm_car (s));
-      if (!it->run_always ())
+      if (it->ok ())
         return true;
-      else
-        run_always_ok = run_always_ok || it->ok ();
     }
-  return run_always_ok;
+  return false;
 }

 bool