Error registering add-on's with identical class names in 2.79 master (buildbot)
Open, NormalPublic


System Information
Windows 10 x64
Renderer: GeForce GTX 860M/PCIe/SSE2

Blender Version
Broken: 2.79.1 b07dcb8
Worked: 2.79 RC2

Short description of error
Register error if two different add-ons have identical class names.
That breaks registration for all of my add-ons.

Exact steps for others to reproduce the error

  1. Open attached blend file:
  2. Run scripts in both Text Editor areas.
  3. You should get register error (like below) while running second script, that doesn't happen with 2.78 or 2.79 RC2.
Traceback (most recent call last):
    File "C:\Users\Username\Desktop\user_pref_error.blend\addon_2", line 20, in <module>
    File "C:\Users\Username\Desktop\user_pref_error.blend\addon_2", line 12, in register
RuntimeError: Error: Type identifier 'Object_A' is already in use: 'Object_A(AddonPreferences)'.



hi @Mikhail Rachinskiy (alm)
the use of duplicate class names has been restricted, we plan to, after 2.79 release, to address these issues.
please note these issues will not be in 2.79 release but are in nightly builds.
it's good to be aware of this issue, i'm trying to keep addons repo clean for 2.79 release, then come in and fix all the issues in nightly, whilst not polluting addons master with fixes that might be conflicting with release.
not closing the task as we may for future ref.

Brendon Murphy (meta-androcto) renamed this task from Error registering add-on's with identical class names to Error registering add-on's with identical class names in 2.79 master (buildbot).Aug 27 2017, 5:20 PM
Brendon Murphy (meta-androcto) triaged this task as Confirmed priority.

Hi guys .. having issue when I enable 'Amaranth Toolset' .. any solution here??
Error code :

Traceback (most recent call last):
  File "/home/model01/Desktop/blender-2.79-9134529b9eb-linux-glibc219-x86_64/2.79/scripts/modules/", line 350, in enable
  File "/home/model01/Desktop/blender-2.79-9134529b9eb-linux-glibc219-x86_64/2.79/scripts/addons_contrib/amaranth/", line 118, in register
  File "/home/model01/Desktop/blender-2.79-9134529b9eb-linux-glibc219-x86_64/2.79/scripts/addons_contrib/amaranth/", line 107, in _call_globals
    getattr(m, attr_name)()
  File "/home/model01/Desktop/blender-2.79-9134529b9eb-linux-glibc219-x86_64/2.79/scripts/addons_contrib/amaranth/animation/", line 136, in register
ValueError: register_class(...): already registered as a subclass

@Souvik Karmakar (souvik) the registration issue in master should be solved. Added a versioning code so it should work with 2.79 release too. Please check the next daily build. Sorry for the wait.

Here on Win10 64bit + Blender 2.79.1 (Hash: a466d7a) 64bit portable the Amaranth Toolset add-on is working fine. Thank you for the fix.

Vuk Gardašević (lijenstina) lowered the priority of this task from Confirmed to Normal.Jan 6 2018, 7:56 AM

Since there weren't new found register errors for a while lowering the priority to Normal. We'll still keep the task open as things can be broken in the future. Well that is not just a possibility, it's the rule :)