Frescobaldi application crashes when creating a blank music sheet

[Yves-Antoine]

This bug only occurs on jammy, with the package frescobaldi included in jammy's repository.

To reproduce the bug, follow these steps :

1. Install the frescobaldi package from the jammy repositories
2. Start frescobaldi (command frescobaldi)
3. In frescobaldi's main window, click on File -> New > Blank music sheet.
A window names "Internal Error - Frescobaldi" opens, containing :

Traceback (most recent call last):
  File "/usr/share/frescobaldi/frescobaldi_app/snippet/menu.py", line 103, in slotTriggered
    self.applySnippet(name)
  File "/usr/share/frescobaldi/frescobaldi_app/snippet/menu.py", line 167, in applySnippet
    engrave.engraver(self.mainwindow()).engrave('preview', d)
  File "/usr/share/frescobaldi/frescobaldi_app/engrave/__init__.py", line 200, in engrave
    self.runJob(job_class(doc, args), doc)
  File "/usr/share/frescobaldi/frescobaldi_app/engrave/__init__.py", line 252, in runJob
    job.manager.manager(document).start_job(j)
  File "/usr/share/frescobaldi/frescobaldi_app/job/manager.py", line 63, in start_job
    app.jobStarted(self.document(), job)
  File "/usr/share/frescobaldi/frescobaldi_app/signals.py", line 191, in emit
    l.call(args, kwargs)
  File "/usr/share/frescobaldi/frescobaldi_app/signals.py", line 308, in call
    return self.func(obj, *args[self.argslice], **kwargs)
  File "/usr/share/frescobaldi/frescobaldi_app/progress.py", line 73, in jobStarted
    self.showProgress(document)
  File "/usr/share/frescobaldi/frescobaldi_app/progress.py", line 59, in showProgress
    self._bar.start(buildtime, j.elapsed_time())
  File "/usr/share/frescobaldi/frescobaldi_app/widgets/progressbar.py", line 74, in start
    self._timeline.setDuration(total * 1000)
TypeError: setDuration(self, int): argument 1 has unexpected type 'float'

The preview right pane is not populated.

Workaround :
1. Download packages python3.qpageview and frescobaldi from
https://packages.ubuntu.com/kinetic/editors/frescobaldi
2. Install downloaded file python3-qpageview_0.6.2-3_all.deb with Gdebi.
3. Install downloaded file frescobaldi_3.2+ds1-1_all.deb with Gdebi.

SRU request :

[Impact]

 * An explanation of the effects of the bug on users
Users of Frescobaldi application (musicians) cannot use the preview feature, which is one of the main advantages of Frescobaldi. There might be other impacts.

 * justification for backporting the fix to the stable release.
Although musicians are a small percentage of the community of Ubuntu users, this application should be bug free on an Ubuntu LTS release, supported during five years.
Also, the workaround suggested above (manual installation of the package files) is not recommended.

 * In addition, it is helpful, but not required, to include an
   explanation of how the upload fixes this bug.
The preview function has been rewritten a a separate Python package.

[Test Plan]

 * detailed instructions how to reproduce the bug
1. Install the frescobaldi package from the jammy repositories
2. Start frescobaldi (command frescobaldi)
3. In frescobaldi's main window, click on File -> New > Blank music sheet.

 * these should allow someone who is not familiar with the affected
   package to reproduce the bug and verify that the updated package fixes
   the problem.

 * if other testing is appropriate to perform before landing this update,
   this should also be described here.

[Where problems could occur]

 * Think about what the upload changes in the software. Imagine the change is
   wrong or breaks something else: how would this show up?
There are two packages which depend on frescobaldi, but only at the "Suggested" level, without referencign a specific version of Frescobaldi:
multimedia-musiciantools is a metapackage: no impact.
multimedia-guitar: I have not tested it, but even if it does not fully work, the new package will be an improvement.
python3.qpageview does not currently exist in Jammy repository, so it won't interfere with any other software.

 * It is assumed that any SRU candidate patch is well-tested before
   upload and has a low overall risk of regression, but it's important
   to make the effort to think about what ''could'' happen in the
   event of a regression.

 * This must '''never''' be "None" or "Low", or entirely an argument as to why
   your upload is low risk.

 * This both shows the SRU team that the risks have been considered,
   and provides guidance to testers in regression-testing the SRU.

[Other Info]

 * Anything else you think is useful to include
 * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board
 * and address these questions in advance

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: frescobaldi 3.1.3+ds1-1
ProcVersionSignature: Ubuntu 5.15.0-43.46-generic 5.15.39
Uname: Linux 5.15.0-43-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Thu Aug 4 13:06:37 2022
InstallationDate: Installed on 2020-05-22 (804 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
PackageArchitecture: all
SourcePackage: frescobaldi
UpgradeStatus: Upgraded to jammy on 2022-07-31 (4 days ago)

--
Yves-Antoine Emmanuelli

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.