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[iOS][IL2CPP] DescriptorValidationException is thrown when using the C# Protobuf library and compiling the Code



To reproduce:

1. Download attached project “" and open in Unity
2. Open “SampleScene” scene
3. Enter Play mode and observe that Console prints two Logs:

Test:Start() (at Assets/Test.cs:17)

{ "code": "PIT-000", "msg": "GetError is returning a custom error" }
Test:Start() (at Assets/Test.cs:18)

4. Exit Play mode
5. Build for iOS
6. Deploy the Xcode project to iOS Device
7. Observe that DescriptorValidationException is thrown in Console

- This issue does not appear on Windows and macOS Standalone (IL2CPP)
- Could not check on Unity 2018.1 and earlier than 2018.2.0a5 because project becomes corrupted

Tested with:
- iPhone 7s Plus, iOS: 12.0 - Reproduced
- iPhone X, iOS: 11.3.1 - Reproduced

Reproduced on Unity 2018.2.0a5, 2018.2.20f1, 2018.3.1f1 and 2019.1.0a13

  1. Response avatar

    Resolution Note (fix version ):

    The problem here is that part of the Google.Protobuf.dll assembly which is used only via reflection is removed by the Unity managed bytecode stripping process. For IL2CPP, Unity always enables managed bytecode stripping, so you will need to indicate that the Google.Protobuf.dll assembly should not be modified.

    This is possible by placing a link.xml file in the Assets/ folder of the project with the following content:

    <assembly fullname="Google.Protobuf" preserve="all"/>

    You can find out more information about the link.xml file here:

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