Freeze on opening when using local time signature and voice2

[mercuree]

Issue type

Crash or freeze

Description with steps to reproduce

This issue is based on a report from https://musescore.org/en/node/373586
UPD. Also reported before https://musescore.org/en/node/373427

I don't know the exact way how the user got this result, but I managed to reproduce it from scratch

1. Create empty score from treble clef template or piano
2. Add 12/8 local time signature
3. Enter 12 eighth notes
4. Enter eighth and eleventh notes for voice 2
5. Remove all rests from voice 2
6. Save and close score
7. Open score again - Freeze

I can't reproduce in Musescore 4.3.2 because it doesn't allow to enter voice 2 in an arbitrary position.
I think this is a regression since 4.4.0

Supporting files, videos and screenshots

freeze_local_time_signature_voice2.mp4

What is the latest version of MuseScore Studio where this issue is present?

MuseScore Studio version (64-bit): 4.5.0-250060307, revision: github-musescore-musescore-0b07b33

Regression

Yes, this used to work in a previous version of MuseScore 4.x

Operating system

windows 10

Additional context

No response

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible

[mathesoncalum]

I carried out quite a long investigation of this last night/this morning (no luck yet). It looks like local time signatures + voices have been problematic since at least MS3. As @mercuree points out, #23911 introduced another way to reach this corruption, but the root cause has been around for a very long time.

timesigvoices.mov

[mercuree]

In MS3 you get a corruption message. I got a lot of these in MS4 too, but it didn't always result in a freeze when opening. Is it possible to fix the freeze at least at this point?
Yes, local time signature is a rarely used feature, but we've already received two complaints on the forum in a short period of time.

[mathesoncalum]

I had a bit of trouble reproducing the freeze earlier but I can do now - I'll look into it.

Edit: It appears the freeze (again, not the underlying corruption) was introduced with #23783. The changes to Measure::fillGap cause an infinite loop inside Measure::checkMeasure.

[Jojo-Schmitz]

I can't reproduce the issue with Mu3