(Case 1297947) Addressables bundle generation is non-deterministic

Unity Engine
,
1

Using Addressables to generate asset bundles, causes the generated asset bundles to be different, even though the content of the source data did not change.

Please see the attached video for a full walk-through.

I tested Unity 2019.4.16f1 and Addressables 1.16.15.

Reproduce

  • Open attached projct
  • Open “Window > Asset Management > Addressables > Groups”
  • In Groups window press “Build > Clean Build > All”
  • In Groups window press “Build > New Build > Default Build Script”
  • Open folder “Library\com.unity.addressables\aa\Windows\StandaloneWindows”
  • Copy samplescene_scenes_all*.bundle to a new folder and call it 1.bundle
  • In Groups window press “Build > Clean Build > All”
  • In Groups window press “Build > New Build > Default Build Script”
  • Open folder “Library\com.unity.addressables\aa\Windows\StandaloneWindows”
  • Copy samplescene_scenes_all*.bundle to a new folder and call it 2.bundle
  • Change the Aspect ratio in GameView
  • Change the Window Layout in the Editor
  • In Groups window press “Build > Clean Build > All”
  • In Groups window press “Build > New Build > Default Build Script”
  • Open folder “Library\com.unity.addressables\aa\Windows\StandaloneWindows”
  • Copy samplescene_scenes_all*.bundle to a new folder and call it 3.bundle
  • Perform a binary compare on the three bundle files, under windows use “fc /b 1.bundle 2.bundle” on the command-prompt

Actual
The generated bundles are bit-wise different.

Expected
Build System outputs bit-wise identical bundles if the source content did not change.

6599899–750487–reproduce_case_1297947.zip (1.28 MB)

9 Likes
2

QA was able to reproduce the issue. Thumbs up!

5 Likes
3

It seems that the issue was maked as fixed in 1.16.15 due to being impossible to reproduce in Unity 2020+.

We are working on 2019.4.18 LTS and just noticed the issue as well.
No apparent data modification (neither from Unity or source control), yet multiple bundles are bitwise different from their counter parts when we build anew.

If the issue is engine side, when can we expect the fix to be backported to 2019 LTS?

Here is one of the many bundles affected, before and after a new build.

6788750–786494–Bundles.zip (61.7 KB)

2 Likes
4

I just received a notification for this thread so I give my two cents.

They didn’t fix it, they marked the issue as “Won’t fix” to avoid allocating resources to uGUI. However, even after 2 years, UI Toolkit still falls short in comparison to uGUI.

I’m genuinely perplexed about how to perceive all of this; nothing seems to work effectively. Working with Unity has become quite frustrating, to be honest. Not only related to this specific issue, but in general.

3 Likes