(Bug): Crash when closing the file picker for Writer node

[platyple]

Make sure to follow our issue report guidelines

• I'm using the latest version of Natron (not required but recommended)
• I've restarted Natron and the issue persists
• I've run Natron via the command line and the issue persists
• I've followed the contributing guidelines to the best of my understanding
• My issue is not on the issue tracker or in a pull request already (go search for it and dig around a little bit!)
• This bug is reproducible

Natron version

Natron Version 2.5

Operating system

Arch Linux

System specs

RAM: 16GB
CPU: AMD Ryzen 5 3600
GPU: AMD Radeon RX 5600

Did you install Natron using the official installer?

• Yes, I used the official installer
• No, I installed from a binary archive
• No, I compiled Natron from sources
• No, I installed Natron via another method

Custom installation path

$HOME/Natron-2.5.0

What were you trying to do?

When closing the file picker dialog that opens when you insert a Writer Node (saving or canceling out), Natron will crash.

What did you expect to happen? What happened instead?

Natron errors out with

free(): invalid pointer
Aborted (core dumped)

I've uploaded a coredump file if that helps at all, the build in question is from the official docker container since that compiles with debug symbols.

Step-by-step reproduction instructions

1. Start Natron
2. Insert a Writer Node
3. Close out of the File Picker in any way

Additional details

I'm happy to try building from the dev branch, so far no luck with compiling natively but the docker route works just fine.

[rodlie]

Not able to replicate using 2.5.0 release or build from RB-2.6 on Ubuntu 24.04.

Are you able to add more info?

• terminal output
• are you using Wayland or X11?

[platyple]

I'm on X11, same results on Wayland.

Terminal Output:

Natron Version 2.5
(C) 2018-2023 The Natron developers
(C) 2013-2018 INRIA and Alexandre Gauthier-Foichat
>>>Use the --help or -h option to print usage.<<<
Fontconfig error: Cannot load default config file: No such file: (null)
Py_SetPythonHome("/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/..")
PYTHONPATH set to /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python310.zip:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10/lib-dynload:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10/site-packages:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../Plugins
Py_Initialize()
PATH is /home/plat/.local/bin:/home/plat/.bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/opt/android-sdk/platform-tools:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/opt/rocm/bin:/usr/lib/rustup/bin
PYTHONPATH is /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python310.zip:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10/lib-dynload:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10/site-packages:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../Plugins
PYTHONHOME is (null)
Py_DebugFlag is 0
Py_VerboseFlag is 0
Py_InteractiveFlag is 0
Py_InspectFlag is 0
Py_OptimizeFlag is 0
Py_NoSiteFlag is 0
Py_BytesWarningFlag is 0
Py_FrozenFlag is 0
Py_HashRandomizationFlag is 1
Py_IsolatedFlag is 0
Py_QuietFlag is 0
Py_IgnoreEnvironmentFlag is 0
Py_DontWriteBytecodeFlag is 0
Py_NoUserSiteDirectory is 1
Py_GetProgramName is Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/Natron
Py_GetPrefix is /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/..
Py_GetExecPrefix is /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/..
Py_GetProgramFullPath is /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/Natron
Py_GetPath is /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python310.zip:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10/lib-dynload:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10/site-packages:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../Plugins:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python310.zip:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10:/home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/../lib/python3.10/lib-dynload
Py_GetPythonHome is /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/bin/..
Info: init.py script not loaded (this is not an error)
Info: initGui.py script not loaded (this is not an error)
free(): invalid pointer

If I had to guess I'd say something in Arch is too new for Natron, considering it works fine on your end

[rodlie]

Thanks for additional info, I don't like Fontconfig error: Cannot load default config file: No such file: (null), this should not happen.

Try move/delete/rename /home/plat/Natron-RB-2.5-202506150956-93c6837-Linux-x86_64-no-installer/lib/libfontconfig.so.1 and see if it works better with the system fontconfig.

[platyple]

It stops complaining about Fontconfig, but it still crashes.

On another note, am I stupid/illiterate or is python2 required to compile Natron?

[rodlie]

It stops complaining about Fontconfig, but it still crashes.

Ok, then it's something else.

On another note, am I stupid/illiterate or is python2 required to compile Natron?

In RB-2.5 I think it defaults to Py2 (if I remember correctly), but it supports Py3.

Building RB-2.6 on Linux should be easy, depending on the distro.

I quickly browsed archlinux.org and this should be enough to build (only) Natron:

• cairo
• expat
• boost-libs
• qt5-base
• python-qtpy
• pyside2 from AUR

Then use CMake to build it.

[platyple]

So I got Natron to compile natively but it segfaults on startup. I fear this is going nowhere.

The Docker route gave me a usable build, all I need/want is Debug Symbols. I may once again be stupid and/or illiterate but how do I tell the Docker container to build with Debug Symbols enabled?

[bipinstha7]

@platyple, did you solve this issue? I got this error on Ubuntu 25.04. It was working earlier, but it's not working now. I think there is some library mismatch with Ubuntu 25.04, do you have any workaround @rodlie ?