ConvertDllsToWebCil fails ugly for invalid assembly

[danmoseley]

Somewhere in this stack it should catch BadImageFormatException and Log.ErrorFromException(..) then return false from the task.
I assume the repro is to feed the task an empty file, or similar.
version: 8.0.4

just after

2024-04-17T00:49:58.7245127Z   Optimizing assemblies for size may change the behavior of the app. Be sure to test after publishing. See: https://aka.ms/dotnet-illink
2024-04-17T00:49:58.7274180Z   Optimizing assemblies for size. This process might take a while.

I get

.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018: The "ConvertDllsToWebCil" task failed unexpectedly. [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018: System.BadImageFormatException: Image is too small. [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at System.Reflection.Throw.ImageTooSmall() [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at System.Reflection.PortableExecutable.PEHeaders..ctor(Stream peStream, Int32 size, Boolean isLoadedImage) [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at System.Reflection.PortableExecutable.PEReader.InitializePEHeaders() [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at System.Reflection.PortableExecutable.PEReader.get_PEHeaders() [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at Microsoft.NET.WebAssembly.Webcil.WebcilConverter.GatherInfo(PEReader peReader, WCFileInfo& wcInfo, PEFileInfo& peInfo) [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at Microsoft.NET.WebAssembly.Webcil.WebcilConverter.ConvertToWebcil() [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at Microsoft.WebAssembly.Build.Tasks.WebcilConverter.ConvertToWebcil() [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at Microsoft.NET.Sdk.WebAssembly.ConvertDllsToWebCil.Execute() [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute() [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]
.../.nuget/packages/microsoft.net.sdk.webassembly.pack/8.0.4/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(452,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(ITaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask) [/home/runner/work/aspire-samples/aspire-samples/samples/Metrics/MetricsApp.Client/MetricsApp.Client.csproj]

https://productionresultssa13.blob.core.windows.net/actions-results/5604d4bc-a8b0-4df9-99a1-482f4b6ac748/workflow-job-run-1d849a45-2f30-5fbb-3226-b730a17a93af/logs/job/job-logs.txt?rsct=text%2Fplain&se=2024-04-17T01%3A10%3A19Z&sig=o0tEe09NJLnPaaMWW9u67PdcAsaTGDKrNhyowktpPiE%3D&sp=r&spr=https&sr=b&st=2024-04-17T01%3A00%3A14Z&sv=2021-12-02

I don't know where the bug is leading to this, perhaps the trimming is producing an empty file, but that's a separate issue.

[sebastienros]

Same thing is happening in aspire-samples here: https://github.com/dotnet/aspire-samples/actions/runs/8680403862/job/23941003242#step:6:245

[lewing]

@sbomer any idea why the trimmer have started producing empty or invalid assemblies recently?

[danmoseley]

I opened this to track the bad error message. If the trimmer is producing an empty file because of a bug rather than something wierd in the aspire-samples build (and this may well be the case, IDK) that would be a separate bug.

It keeps happening there, though eg https://github.com/dotnet/aspire-samples/actions/runs/8725954534/job/23940133588?pr=209 sometimes Windows sometimes Linux.

[sbomer]

@sbomer any idea why the trimmer have started producing empty or invalid assemblies recently?

No. We recently changed some of the PE headers in #101038, but I don't see how that would lead to this crash, and especially not nondeterministically.

Can we confirm which file is being passed to ConvertDllsToWebCil that is causing the failure?

[DamianEdwards]

As @sebastienros points out, this is happening quite a lot in the CI for dotnet/aspire-samples, specifically on this project: https://github.com/dotnet/aspire-samples/tree/996dd5e7909ef60a561e6372ad40559441f66b91/samples/Metrics/MetricsApp.Client

[maraf]

A workaround for the time being is to set WasmEnableWebcil=false

[maraf]

Could it be a some kind of race condition from running the publish in parallel?

https://github.com/dotnet/aspire-samples/blob/main/build/Build.proj#L29

[sebastienros]

@maraf I created this PR to disable it dotnet/aspire-samples#214 but this does the same thing.

[maraf]

I believe this inner parallel double publish dotnet/aspire-samples#214 (comment) is also the root case of this issue with empty trimmed dlls

EDIT: Confirmed, the ConvertDllsToWebCil is running in both parallel publishes for the same project.

[javiercn]

@maraf just in case its due to some of the workarounds I had to add for my work, I've created a PR that removes them dotnet/sdk#39689