[Known Build Error] Failed webcil conversion: image is too small

[ilonatommy]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1043546&view=logs&j=d9092465-e29c-5735-3051-a3146222728b
Build error leg or test failing: Build / Test: Windows local development validation / Build (Release)
Pull request: #61748

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": "",
  "ErrorPattern": "error : Failed to convert .*.dll' to webcil: Image is too small.",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

 Wasm.Performance.TestApp (Blazor output) -> D:\a\_work\1\s\src\Components\benchmarkapps\Wasm.Performance\TestApp\bin\Release\net10.0\wwwroot
  Optimizing assemblies for size may change the behavior of the app. Be sure to test after publishing. See: https://aka.ms/dotnet-illink
  Optimizing assemblies for size. This process might take a while.
C:\Users\cloudtest\.nuget\packages\microsoft.net.sdk.webassembly.pack\10.0.0-preview.5.25260.104\build\Microsoft.NET.Sdk.WebAssembly.Browser.targets(631,5): error : Failed to convert 'D:\a\_work\1\s\artifacts\obj\BasicTestApp\Release\net10.0\linked\System.Private.Xml.dll' to webcil: Image is too small. [D:\a\_work\1\s\src\Components\test\testassets\BasicTestApp\BasicTestApp.csproj]
  Publishing without optimizations. Although it's optional for Blazor, we strongly recommend using `wasm-tools` workload! You can install it by running `dotnet workload install wasm-tools` from the command line.
  BasicTestApp -> D:\a\_work\1\s\src\Components\test\E2ETest\bin\Release\net10.0\trimmed-or-threading\BasicTestApp\

The exception is thrown by PEBinaryReader in
https://github.com/dotnet/runtime/blob/2e77d32dfcd5465434e4b0963e9be50b749521f6/src/libraries/System.Reflection.Metadata/src/System/Reflection/PortableExecutable/PEBinaryReader.cs#L118
called by
https://github.com/dotnet/runtime/blob/2e77d32dfcd5465434e4b0963e9be50b749521f6/src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/ConvertDllsToWebCil.cs#L70

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1043546
Error message validated: [error : Failed to convert .*.dll' to webcil: Image is too small.]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 5/19/2025 7:10:00 AM UTC

Report

Build	Definition	Step Name	Console log	Pull Request
1190764	dotnet/aspnetcore	Build (Release)	Log	#64214
1173385	dotnet/aspnetcore	Build (Release)	Log	#64020

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	1	2

[SilverioMiranda]

Same here : /opt/azagent/_work/2/.nuget/packages/microsoft.net.sdk.webassembly.pack/9.0.7/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets(506,5): error : Failed to convert '/opt/azagent/_work/2/s/src/SRM.Login.Admin/SRM.Login.Admin.Client/obj/Debug/net9.0/linked/System.Private.CoreLib.dll' to webcil: Image is too small. [/opt/azagent/_work/2/s/src/SRM.Login.Admin/SRM.Login.Admin.Client/SRM.Login.Admin.Client.csproj]

[maraf]

It happens during publish on ILLinked dlls. The System.Private.Xml.dll could have been linked to "0", but there is no chance it could happen for System.Private.CoreLib.dll. It looks like some race condition.

Duplicate of dotnet/runtime#111698

[maraf]

Also dotnet/runtime#101154 in which is was caused by publish run in parallel.

@SilverioMiranda Are you publishing only a server project or whole solution?

[maraf]

A possible workaround could be to generate temp webcil files to a guid-containing folder