Wasm Exception when adding a RepeatBehavior and a Duration to a Storyboard - uno-platform

Question

I am trying to show a simple flashing animation in WebAssembly using VisualStates and Storyboards. I am getting the following exception when adding both a Duration and RepeatBehavior='Forever' to a Storyboard:
Error
at 631680 (dotnet.js:1)
at _emscripten_asm_const_iii (dotnet.js:1)
at wasm_logger (:58006/<anonymous>:wasm-function[3132]:0x9dfb7)
at eglib_log_adapter (:58006/<anonymous>:wasm-function[6071]:0x112d92)
at monoeg_g_logstr (:58006/<anonymous>:wasm-function[4608]:0xcd55a)
at monoeg_g_logv_nofree (:58006/<anonymous>:wasm-function[2196]:0x63d92)
at monoeg_assertion_message (:58006/<anonymous>:wasm-function[429]:0xd35c)
at mono_assertion_message_unreachable (:58006/<anonymous>:wasm-function[144]:0x347c)
at interp_exec_method (:58006/<anonymous>:wasm-function[1380]:0x2fa40)
at interp_runtime_invoke (:58006/<anonymous>:wasm-function[5695]:0xfb19a)
Uno.UI.js:97 Unhandled dispatcher exception: RuntimeError: abort(undefined). Build with -s ASSERTIONS=1 for more info. (RuntimeError: abort(undefined). Build with -s ASSERTIONS=1 for more info.
at abort (http://localhost:58006/package_e0b2677001d484af549b92b1436e81abf6d3eb6b/dotnet.js:1:16059)
at _abort (http://localhost:58006/package_e0b2677001d484af549b92b1436e81abf6d3eb6b/dotnet.js:1:117947)
at wasm_logger (<anonymous>:wasm-function[3132]:0x9dfd9)
at eglib_log_adapter (<anonymous>:wasm-function[6071]:0x112d92)
at monoeg_g_logstr (<anonymous>:wasm-function[4608]:0xcd55a)
at monoeg_g_logv_nofree (<anonymous>:wasm-function[2196]:0x63d92)
at monoeg_assertion_message (<anonymous>:wasm-function[429]:0xd35c)
at mono_assertion_message_unreachable (<anonymous>:wasm-function[144]:0x347c)
at interp_exec_method (<anonymous>:wasm-function[1380]:0x2fa40)
at interp_runtime_invoke (<anonymous>:wasm-function[5695]:0xfb19a))
Uno.UI.js:98 Uncaught RuntimeError: abort(undefined). Build with -s ASSERTIONS=1 for more info.
at abort (http://localhost:58006/package_e0b2677001d484af549b92b1436e81abf6d3eb6b/dotnet.js:1:16059)
at _abort (http://localhost:58006/package_e0b2677001d484af549b92b1436e81abf6d3eb6b/dotnet.js:1:117947)
at wasm_logger (<anonymous>:wasm-function[3132]:0x9dfd9)
at eglib_log_adapter (<anonymous>:wasm-function[6071]:0x112d92)
at monoeg_g_logstr (<anonymous>:wasm-function[4608]:0xcd55a)
at monoeg_g_logv_nofree (<anonymous>:wasm-function[2196]:0x63d92)
at monoeg_assertion_message (<anonymous>:wasm-function[429]:0xd35c)
at mono_assertion_message_unreachable (<anonymous>:wasm-function[144]:0x347c)
at interp_exec_method (<anonymous>:wasm-function[1380]:0x2fa40)
at interp_runtime_invoke (<anonymous>:wasm-function[5695]:0xfb19a)
Uno.UI.js:97 Unhandled dispatcher exception: RuntimeError: memory access out of bounds (RuntimeError: memory access out of bounds
at malloc (<anonymous>:wasm-function[359]:0xa47e)
at monoeg_malloc (<anonymous>:wasm-function[161]:0x3e0f)
at mono_mempool_new_size (<anonymous>:wasm-function[629]:0x12bce)
at generate (<anonymous>:wasm-function[5909]:0x107b81)
at mono_interp_transform_method (<anonymous>:wasm-function[1290]:0x2b57b)
at do_transform_method (<anonymous>:wasm-function[2959]:0x93ac4)
at interp_exec_method (<anonymous>:wasm-function[1380]:0x2eda7)
at interp_runtime_invoke (<anonymous>:wasm-function[5695]:0xfb19a)
at mono_jit_runtime_invoke (<anonymous>:wasm-function[5149]:0xe196b)
at do_runtime_invoke (<anonymous>:wasm-function[1411]:0x3ea94))
Uno.UI.js:98 Uncaught RuntimeError: memory access out of bounds
at malloc (<anonymous>:wasm-function[359]:0xa47e)
at monoeg_malloc (<anonymous>:wasm-function[161]:0x3e0f)
at mono_mempool_new_size (<anonymous>:wasm-function[629]:0x12bce)
at generate (<anonymous>:wasm-function[5909]:0x107b81)
at mono_interp_transform_method (<anonymous>:wasm-function[1290]:0x2b57b)
at do_transform_method (<anonymous>:wasm-function[2959]:0x93ac4)
at interp_exec_method (<anonymous>:wasm-function[1380]:0x2eda7)
at interp_runtime_invoke (<anonymous>:wasm-function[5695]:0xfb19a)
at mono_jit_runtime_invoke (<anonymous>:wasm-function[5149]:0xe196b)
at do_runtime_invoke (<anonymous>:wasm-function[1411]:0x3ea94)
dotnet.js:1 Thread 0x1 may have been prematurely finalized* Assertion at /__w/1/s/mono/mono/utils/mono-threads.c:702, condition `<disabled>' not met
Uno.UI.js:97 Unhandled dispatcher exception: [object Object] (undefined)
Uno.UI.js:98 Uncaught ExitStatus {name: "ExitStatus", message: "Program terminated with exit(0)", status: 0}
dotnet.js:1 * Assertion: should not be reached at /__w/1/s/mono/mono/utils/mono-threads-coop.h:48
dotnet.js:1 Uncaught ExitStatus {name: "ExitStatus", message: "Program terminated with exit(0)", status: 0}
dotnet.js:1 * Assertion at /__w/1/s/mono/mono/utils/mono-internal-hash.c:47, condition `<disabled>' not met
dotnet.js:1 Uncaught ExitStatus {name: "ExitStatus", message: "Program terminated with exit(0)", status: 0}
The xaml causing the above error is:
<Grid Background="White" BorderBrush="Gray" BorderThickness="1" Width="250" Height="250">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="LightStates">
<VisualState x:Name="LightFlashing">
<Storyboard Duration="0:0:2.0" RepeatBehavior="Forever">
<DoubleAnimation From="1" To="0" Storyboard.TargetName="AnimatedEllipse" Storyboard.TargetProperty="Opacity" />
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Ellipse x:Name="AnimatedEllipse" Height="126" Width="126">
<Ellipse.Fill>
<SolidColorBrush x:Name="AnimatedEllipseBrush" Color="Red" />
</Ellipse.Fill>
</Ellipse>
</Grid>
Removing Duration from the Storyboard and adding it to DoubleAnimation is working correctly, no errors. Uno.Wasm.Bootstrap version is 1.3.0-dev.44

Answer 1

This is a bug in Uno Platform, I have created an issue for it on GitHub. The same problem presumably appears on all targets, the workaround before it is fixed is, as you mentioned, to keep the Duration attribute on the DoubleAnimation. Thanks for reporting it!