#5767 Assertion failure with manual pageBreak

[Thomas Morley]

After the fix for https://sourceforge.net/p/testlilyissues/issues/4943/ done in https://sourceforge.net/p/testlilyissues/issues/5725/
One of the reported assertion failures persists https://sourceforge.net/p/testlilyissues/issues/4943/#b3ae

Valentin Villenave - 2019-01-10

A similar crash has been reported on -user-fr, which I was able to trim down to the minimal example below (commenting any line solves the bug). Interestingly though, this one’s reproducible even on GNU/Linux. (Whereas the previous snippets in this ticket aren’t.)

\version "2.19.80"
% 2.18.2 doesn’t crash, whilst 2.21.0 still does.

\header { title = "foo bar" }

{
\pageBreak
c'1 \break
c' \break
\repeat unfold 4 c'
}

Here’s the log on GNU/Linux:

page-breaking.cc:1052: void Page_breaking::line_divisions_rec(vsize, const Line_division&, const Line_division&, Page_breaking::Line_division*): Assertion `my_index == 0' failed.
Aborted (core dumped)

[Thomas Morley]

related:
https://sourceforge.net/p/testlilyissues/issues/5651/