Ubuntu 24.04 Installation and Execution Issues

[stephanschielke]

Summary

PhotoGlimmer fails to launch on Ubuntu 24.04 due to PySide2/Qt library compatibility issues, affecting both source code execution and AppImage distribution.

Environment Details

• Operating System: Ubuntu 24.04 (Linux 6.12.10-76061203-generic)
• Python Version: 3.10.18 (managed via mise)

Error Description

Primary Error

ImportError: ~/.local/share/mise/installs/python/3.10.18/lib/python3.10/site-packages/PySide2/QtUiTools.so: undefined symbol: _ZdlPvm, version Qt_5

Error Context

• Occurs when: Importing PySide2.QtUiTools.QUiLoader
• Affects: Both source code execution and AppImage distribution
• Location: PhotoGlimmer UI initialization in photoglimmer_ui.py

Full Error Traceback

Traceback (most recent call last):
  File "~/Code/PhotoGlimmer/src/photoglimmer/app.py", line 17, in <module>
    from .photoglimmer_ui import PhotoGlimmerMainWindow
  File "~/Code/PhotoGlimmer/src/photoglimmer/photoglimmer_ui.py", line 11, in <module>
    from PySide2.QtUiTools import QUiLoader
ImportError: ~/.local/share/mise/installs/python/3.10.18/lib/python3.10/site-packages/PySide2/QtUiTools.so: undefined symbol: _ZdlPvm, version Qt_5

Steps to Reproduce

1. Install Ubuntu 24.04
2. Set up Python 3.10.18 (via mise)
3. Install PySide2 5.15.2.1 via pip
4. Attempt to run PhotoGlimmer from source: python -m photoglimmer
5. Alternatively, try running the AppImage distribution

Troubleshooting Steps Attempted

1. Environment Verification

• ✅ Confirmed Python version (3.10.18) and virtual environment setup
• ✅ Verified PySide2 and Shiboken2 versions (both 5.15.2.1)
• ✅ Checked Python path points to correct mise-managed installation

2. Qt Library Management

• ✅ Initially attempted Qt6 removal: sudo apt-get remove --purge 'libqt6*'
  • Note: Required quotes due to zsh glob pattern handling
• ✅ Successfully removed Qt6 libraries from system
• ✅ Confirmed only Qt5 libraries remain installed

3. PySide2 Reinstallation Attempts

• ✅ Multiple pip uninstall/install cycles for PySide2 and Shiboken2
• ✅ Attempted installation from different sources
• ❌ All reinstallation attempts failed to resolve the issue

4. System Library Verification

• ✅ Confirmed Qt6 libraries were successfully removed
• ✅ Verified system Qt5 libraries are present
• ❌ ABI compatibility issues persist

Root Cause Analysis

Technical Analysis

The error undefined symbol: _ZdlPvm, version Qt_5 indicates an ABI (Application Binary Interface) incompatibility between:

• PySide2 5.15.2.1 expecting specific Qt5 symbol definitions
• Ubuntu 24.04's Qt library configuration providing incompatible symbols

Symbol Analysis

• _ZdlPvm is a mangled C++ symbol related to Qt5 memory management
• The symbol exists but with incompatible versioning/ABI signature
• This suggests Ubuntu 24.04's Qt5 libraries have ABI changes that break PySide2 compatibility

Distribution Impact

• Source Code: Fails to execute due to PySide2 import issues
• AppImage: Should be self-contained but appears affected by host system Qt libraries
• deb Package: Would likely face the same Qt compatibility issues

Proposed Solutions

Short-term Workarounds

1. Use Ubuntu 22.04: Recommend users stick with Ubuntu 22.04 LTS
2. Docker Container: Provide Ubuntu 22.04-based Docker image
3. Conda Environment: Use conda-forge PySide2 packages which may have better compatibility

Long-term Solutions

1. Migrate to PySide6:

   • Upgrade codebase to use PySide6 (Qt6)
   • Better Ubuntu 24.04 compatibility
   • Future-proof solution
   • Migrate from PySide2 to PySide6 to Fix Qt Symbol Compatibility Issues #3

2. Improve AppImage Bundling:

   • Ensure Qt libraries are properly bundled in AppImage
   • Static linking of Qt dependencies where possible
   • Test AppImage isolation on various distributions

Additional Notes

Environment Dependencies

PhotoGlimmer's current dependency on PySide2 5.15.2.1 creates a constraint that conflicts with Ubuntu 24.04's Qt library ecosystem. This is a common issue affecting many Qt/PySide2 applications on newer Ubuntu releases.

[stephanschielke]

And as a sidenote:

sudo dpkg --install photoglimmer_0.4.0-1.ubuntu-jammy_amd64.deb
Selecting previously unselected package photoglimmer.
(Reading database ... 385676 files and directories currently installed.)
Preparing to unpack .../photoglimmer_0.4.0-1.ubuntu-jammy_amd64.deb ...
Unpacking photoglimmer (0.4.0) ...
dpkg: dependency problems prevent configuration of photoglimmer:
 photoglimmer depends on libpython3.10; however:
  Package libpython3.10 is not installed.

dpkg: error processing package photoglimmer (--install):
 dependency problems - leaving unconfigured
...
Processing triggers for man-db (2.12.0-4build2) ...
Errors were encountered while processing:
 photoglimmer

The ubuntu-jammy deb package obviously fails on Ubuntu 24.10 because of the hard dependency of libpython3.10 (rather than libpython3.12)

[codecliff]

@stephanschielke Hi! Thanks a lot for your contribution looking at it and will revert to you over the weekend, PS - i'm surprised with the _ZdlPvm, error in appimage . Did not expect it to leak a library dependency. Let me run some checks.