3.6 won't build on Linux (Slackware)

• Jan 15, 2021 - 10:28

When building from source, build failes with the following error:
“CMake Error at build/FindQt5.cmake:43 (message):
MuseScore 3 does not support Qt 5.15: 5.15.0 shows empty palettes panel,
5.15.1 and later crash when opening pre-3.6 scores due to QTBUG-77337
Call Stack (most recent call first):
CMakeLists.txt:84 (include)

— Configuring incomplete, errors occurred!”

I found that odd, since I built the 3.6-RC less than a week ago (with qt-5.15.2). Worked perfectly. No issues with palettes or opening old scores.

After commenting out lines 40-45 in Musescore-3.6/build/FindQt5.cmake I managed to build a package. MuseScore seems to run as it should after upgrade. No issues with palettes or with opening scores created in mscore-3.5. I haven’t tested all functions, of course.


Comments

MuseScore 3.x indeed doesn't work nor build with Qt 5.15, for exactly the reasons you descibed.
The crash in .1 and .2 should happen in the Score Migration dialog, seen only if 'importing' pre-3.6 scores. Not sure whether this does affect all platforms though, I'm very sure that it did affect Windows (up to at least the 3.6 Beta). I'd be very glad to hear if that no longer is the case, and for all platforms.

For now best use the latest LTS before that, 5.12.10

MuseScore 4, the master branch, in turn does require Qt 5.15 and won't even build with anything below that.

In reply to by Jojo-Schmitz

It might well affect Windows, but apparently not Linux since (as I wrote) 3.6 builds OK with the mentioned lines in FindQt5.cmake commented out. No problems with importing pre-3.6 scores.
When looking at FindQt5.cmake, line 40 reads

if(NOT ${CMAKE_HOST_SYSTEM_NAME} MATCHES "Windows")

As I understand it, this line should lead to that a non-Windows system disregards the following 5 lines, but apparently not.

In reply to by Jojo-Schmitz

Ah yes, my fault.
But it doesn't change the fact that I could build MuseScore-3.6 on Linux with Qt5.15 (at least with 5.15.2, don't know about earlier versions). If other Linux users could confirm this, maybe the FindQt5.cmake file could be changed accordingly.

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