net9.0 Blazor Server NU1102 on dotnet restore --runtime linux-x64

[Wuz3t]

Description

Hi,

I'm trying to use dontet restore --runtime linux-x64. Restore is failed with message:
error NU1102: Unable to find package Microsoft.NETCore.App.Runtime.Mono.linux-x64 with version (= 9.0.0)

Above line is used in my docker file. It started to crash after updating from .net8 to .net9

Reproduction Steps

• create clear .net 9 Blazor Web App.
• run dontet restore --runtime linux-x64

Expected behavior

dontet restore is finished without arrors

Actual behavior

command finishes with message: error NU1102: Unable to find package Microsoft.NETCore.App.Runtime.Mono.linux-x64 with version (= 9.0.0)

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

It is specific to restore, buld works fine.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing
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[jeffschwMSFT]

That runtime package has been deprecated, here is the breaking change - dotnet/docs#41366.

Please share the exact steps taken to hit this. The command 'dotnet restore --runtime linux-x64' should not be trying to restore the mono runtime pack.

[dotnet-policy-service]

Tagging subscribers to this area: @mangod9
See info in area-owners.md if you want to be subscribed.

[L-Sypniewski]

I'm having the same issue both when building the docker image and executing dotnet restore Frontend.sln --runtime linux-x64 locally on Ubuntu 24.04:

FROM mcr.microsoft.com/dotnet/sdk:9.0.101-noble-amd64 AS restore
WORKDIR /src

# Copy solution file, project files, and props files
COPY *.sln */*.csproj Directory.Build.props Directory.Packages.props ./
RUN for file in $(ls *.csproj); do mkdir -p ${file%.*}/ && mv $file ${file%.*}/; done

# Restore packages with specific runtime identifier
RUN dotnet restore Frontend.sln --runtime linux-x64

FROM restore AS build
ARG BUILD_CONFIGURATION=Release
# Copy the rest of the source files
COPY . .
WORKDIR /src
RUN dotnet build Blazor/Blazor.csproj --no-restore -c $BUILD_CONFIGURATION -r linux-x64 

FROM build AS publish
ARG BUILD_CONFIGURATION=Release
RUN dotnet publish Blazor/Blazor.csproj --no-restore --no-build -c $BUILD_CONFIGURATION -r linux-x64  -o /app/publish

FROM mcr.microsoft.com/dotnet/aspnet:9.0.0-noble-chiseled-extra-amd64 AS final
WORKDIR /app
COPY --from=publish /app/publish .
USER app
EXPOSE 8080
ENTRYPOINT ["dotnet", "Blazor.dll"]

The solution contains ASP NET Core and Web Assembly projects, both migrated to NET 9 and using the latest nuget packages.

[steveisok]

@lewing I think this is <UseMonoRuntime> set for all cases likely as a result of targeting wasm somewhere. I think it needs to be fixed inside the blazor build.

[upCASE]

Is there any news to this? I see the fix being merged, but it still doesn't work.
We wanted to try .NET 9, but hit the same error in our builds. Very annoying...