Crash when multi-measure rests are enabled and press End

Confirm, it's as simple to reproduce as:

1) default empty score
2) press "M"
3) press "End"

Crash happens in ScoreView::pageEnd(), we grab score()->last() which is the last measurebase and then try to access its system, but the last measure has no system because it is covered by an mmrest. I'll see about a fix.

Actually, it looks like other page / screen navigation commands may have similar issues, maybe someone else wants to take a look. Some of it at least seems to be a regression in 3.3 - see https://github.com/musescore/MuseScore/pull/4803

Confirmed. Not an issue with 3.2.3 but with 3.3 RC, so a regression that needs fixing before 3.3 gets released

This issue appears in last August.

• This nightly works (August, 4): 5979345
• Not this one (August, 17): 6f97e3b
  This would confirm I guess that the origin would indeed be here ? https://github.com/musescore/MuseScore/pull/4803
  ( I see two other commits this day about navigation, but less likely or not at all involved ?)

I see 2 possible fixes for this particular crash

1. use score()->lastMeasureMM() instead of score()->last()
2. check for lm->system() to be not NULL before accessing lm->system()->page()->width()

Or even both.

screenNext(), screenPrev(), pageNext(), pagePrev() and pageTop() seem to not be affected by this issue (i.e. don't crash), just pageEnd(), only that accesses lm->system()

see https://github.com/musescore/MuseScore/pull/5415. As score()->last() works just fine in screenNext(), screenPrev(), pageNext(), pagePrev() and pageTop(), I went for option 2

Fixed in branch master, commit b84d499896

_fix #296034: Crash when multi-measure rests are enabled and press End

also consistenltly use lastMeasureMM() rather than last() in other
places of that file_

Fixed in branch master, commit 63445133b5

_Merge pull request #5415 from Jojo-Schmitz/page-end-crash

fix #296034: Crash when multi-measure rests are enabled and press End_

Automatically closed -- issue fixed for 2 weeks with no activity.