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[Erich Eickmeyer <1877806@xxxxxxxxxxxxxxxxxx>]

** Changed in: lilv (Ubuntu Focal)
     Assignee: Erich Eickmeyer (eeickmeyer) => (unassigned)

** Changed in: lilv (Ubuntu Focal)
       Status: In Progress => Confirmed

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https://bugs.launchpad.net/bugs/1877806

Title:
  [SRU] ardour crashes when saving lv2 plugin preset - bug discovered in
  lilv

Status in ardour package in Ubuntu:
  Triaged
Status in lilv package in Ubuntu:
  Fix Released
Status in ardour source package in Focal:
  Triaged
Status in lilv source package in Focal:
  Confirmed
Status in lilv source package in Groovy:
  Fix Released

Bug description:
  [Impact]

   * Users of Ardour who wish to use LV2 audio plugins and make settings
     presets are running into an issue where they are unable to save changes
     to their presets. Attempts simply crash the application.

   * This has been only been observed in Ubuntu 20.04 LTS. Attempts to
     reproduce the behavior on 18.04, 19.10, and Groovy Gorilla proved
     fruitless.

   * Upon investigation, the bug was a regression in lilv 0.24.6 which was
     corrected in 0.24.8 per https://github.com/lv2/lilv/issues/32 and its 
     attached commit.

  [Test Case]

   * In Ardour, start a new project, go to the Mixer view.

   * Add a track to the project

   * Add any LV2 plugin to the track

   * Open the LV2 plugin interface via a double-click on the plugin

   * Save a "New" preset, use any name.

   * Make a change to the plugin state (any parameter), click "Save".
     Ardour will crash.

  [Regression Potential]

   * This library (lilv) affects LV2 plugins and only LV2 plugins. Version 
     0.24.8 contains a number of bugfixes to enhance the stability of LV2
     plugins, including the bugfix mentioned.

   * Even though this version contains a number of bug fixes, there is always
     potential for some regression in LV2 plugins to occur, such as 
     misbehavior or other regressions similar to this particular bug.

  [Other Info]
   
   * The diff in this case is quite large due to the number of bugs fixed. 
     While it is possible for a simple cherry pick of the commit in question,
     I believe there is an even greater risk of regression or bugs appearing 
     if the full bugfix release is not used.

   * The full bugfix release (0.24.8) fixes many bugs and does not contain
     any new features as far as I can tell.

  
  Original bug follows:

  The few lv2 plugins I have tried all crash ardour when I click on
  "save" to save the preset. Clicking Add to create a new plugin doesn't
  crash, but it also does not save the preset.  If you load a plugin
  preset already created and then click save, you end up wiping out the
  contents of the preset direcoty in ~/.lv2.  The .ttl files are deleted
  and you end up with an empty directoy.  The only thing printed on the
  console when this happens is this:

  CALF DEBUG: instance 0x55c00d102860 data 0x55c01ca1cf10
  CALF DEBUG: calf 0x7f8d31f7b0f0 cpi 0x7f8d31783ca0
  Segmentation fault (core dumped)

  AFAIK, teh preset add and save functions work for ladspa plugins.

  -Don

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: ardour 1:5.12.0-3ubuntu4
  ProcVersionSignature: Ubuntu 5.4.0-29.33-lowlatency 5.4.30
  Uname: Linux 5.4.0-29-lowlatency x86_64
  ApportVersion: 2.20.11-0ubuntu27
  Architecture: amd64
  CasperMD5CheckResult: skip
  CurrentDesktop: XFCE
  Date: Sat May  9 21:39:09 2020
  InstallationDate: Installed on 2020-04-26 (13 days ago)
  InstallationMedia: Ubuntu-Studio 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
  SourcePackage: ardour
  UpgradeStatus: No upgrade log present (probably fresh install)

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