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Asset Bundle built in 2017.3 are crashing in iOS app built with 2018.1.0f1

Discussion in 'iOS and tvOS' started by rchapman, May 1, 2018.

  1. rchapman

    rchapman

    Joined:
    Feb 13, 2014
    Posts:
    43
    Just switched to 2018.1.0f1 to address Vuforia bugs, but now asset bundles that we built in 2017.3 are crashing my iOS build. We've already dealt with one round of crashes moving from 2017.2 -> 2017.3.

    This is the crash:

    -[MTLVertexAttributeDescriptorArrayInternal setObject:atIndexedSubscript:], line 396: error 'vertex attribute index (18446744073709551615) must be < 31.'

    -[MTLVertexAttributeDescriptorArrayInternal setObject:atIndexedSubscript:]:396: failed assertion `vertex attribute index (18446744073709551615) must be < 31.'

    I would like to know if this should be supported or if we're going to be required to update our assets yet again. This will be a huge issue if required. Unity needs to make it very clear if an engine update will break with incompatible asset bundles. I would say that having them break every time there's an update makes them significantly less useful.
     
  2. TheJimz

    TheJimz

    Joined:
    Jun 26, 2015
    Posts:
    49
    I think it's entirely reasonable to expect you would need to rebuild asset bundles in the current version of unity you are using.
     
  3. rchapman

    rchapman

    Joined:
    Feb 13, 2014
    Posts:
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    That expectation should be set by documentation, not a forum thread. I haven't been able to find any official documents that describe asset bundle compatibility, but I'd be happy to be proven wrong. At a minimum the release notes should highlight this if a new version is going to require all bundles to be rebuilt and the 2018 release notes make no mention of this.
     
  4. Aurimas-Cernius

    Aurimas-Cernius

    Unity Technologies

    Joined:
    Jul 31, 2013
    Posts:
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    AssetsBundles aren't strictly required to be rebuilt to be loadable by newer Unity version, but there is no full backward compatibility either. It all comes down to what is inside the bundle.
    So, in essence, you need to either test your asset bundles thoroughly to ensure they are still compatible or rebuild them.
     
  5. halilkayim

    halilkayim

    Joined:
    Feb 27, 2018
    Posts:
    21
    I have hundreds of asset bundles stored in my server and I download and use them in my client app. Having to rebuild every one of them would be a big strain for us. I need to know a couple of things before going through with this. What passes as incompatible and compatible? Will rebuilding my bundles definitely solve this problem? If I want to go back to using Unity 2017.4, will the bundles built with 2018.1 cause a similar problem?
     
  6. Aurimas-Cernius

    Aurimas-Cernius

    Unity Technologies

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    Jul 31, 2013
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    That question should be asked in Asset Bundles forum as the experts on this are there.
    But in general graphics stuff (like shaders) tend to have problems across versions, while things like audio clips don't have problems. Older unity version of player and newer unity version of assets bundles is strongly not recommended.
     
  7. re-cheid

    re-cheid

    Joined:
    Apr 10, 2017
    Posts:
    9
    @rchapman
    Any new findings on this topic?

    @Aurimas-Cernius
    We're facing the same problem, Asset bundle was built using Unity 2018.1.1f1 and the app with Unity 2018.1.0.f2.
    Could this really be this much of an issue even between minor releases?
    Android and Windows Store apps work fine (even when the bundle was built back in 2017.3)

    I can't seem to find the "Asset Bundles" forum, only found the one for promoting Assets from the store.

    BR,
    Chris
     
  8. Aurimas-Cernius

    Aurimas-Cernius

    Unity Technologies

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    Jul 31, 2013
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    2,320
  9. re-cheid

    re-cheid

    Joined:
    Apr 10, 2017
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    9