Cannot `dotnet format` ASP.NET Core projects

After upgrading to 6.0.2 (6.0.200) I got errors when trying to format projects using the web SDK, i.e.

<Project Sdk="Microsoft.NET.Sdk.Web">

Initially I assumed that I had something wrong or unexpected in the project I was working on and/or in my environment, as the error is basically the same as that in https://github.com/dotnet/format/issues/1500; unfortunately in my case even removing all other SDKs did not fix the issue.

EDIT: since the report, new docker images have been released; the reproducer is now much simpler: https://github.com/dotnet/format/issues/1519#issuecomment-1043607496

I tried to reproduce it using one of the standard docker images, but the latest ones are 6.0.102, not 6.0.200, so I wrote this Dockerfile. Its first stage is based on https://github.com/dotnet/dotnet-docker/blob/17971807fc0f4ff5a0eca53deb2d85fff990d95c/src/sdk/6.0/bullseye-slim/amd64/Dockerfile updating just DOTNET_SDK_VERSION and dotnet_sha512 The second stage is the actual reproducer: it creates a simple webapp (from the template) and tries to format it

ARG REPO=mcr.microsoft.com/dotnet/aspnet
FROM $REPO:6.0.2-bullseye-slim-amd64 AS sdk-6.0.200

ENV \
    # Unset ASPNETCORE_URLS from aspnet base image
    ASPNETCORE_URLS= \
    # Do not generate certificate
    DOTNET_GENERATE_ASPNET_CERTIFICATE=false \
    # Do not show first run text
    DOTNET_NOLOGO=true \
    # SDK version
    DOTNET_SDK_VERSION=6.0.200 \
    # Enable correct mode for dotnet watch (only mode supported in a container)
    DOTNET_USE_POLLING_FILE_WATCHER=true \
    # Unset Logging__Console__FormatterName from aspnet base image
    Logging__Console__FormatterName= \
    # Skip extraction of XML docs - generally not useful within an image/container - helps performance
    NUGET_XMLDOC_MODE=skip \
    # PowerShell telemetry for docker image usage
    POWERSHELL_DISTRIBUTION_CHANNEL=PSDocker-DotnetSDK-Debian-11

RUN apt-get update \
    && apt-get install -y --no-install-recommends \
        curl \
        git \
        wget \
    && rm -rf /var/lib/apt/lists/*

# Install .NET SDK
RUN curl -fSL --output dotnet.tar.gz https://dotnetcli.azureedge.net/dotnet/Sdk/$DOTNET_SDK_VERSION/dotnet-sdk-$DOTNET_SDK_VERSION-linux-x64.tar.gz \
    && dotnet_sha512='334f3ea4bfeb736bed61c5896796a09d640b0ae74605c514edc5869c395befb7cfc795b58c922f14560e7d41c89c073c62ed01eefc6d9f13aa916e3478949c24' \
    && echo "$dotnet_sha512  dotnet.tar.gz" | sha512sum -c - \
    && mkdir -p /usr/share/dotnet \
    && tar -oxzf dotnet.tar.gz -C /usr/share/dotnet ./packs ./sdk ./sdk-manifests ./templates ./LICENSE.txt ./ThirdPartyNotices.txt \
    && rm dotnet.tar.gz \
    # Trigger first run experience by running arbitrary cmd
    && dotnet help

# Install PowerShell global tool
RUN powershell_version=7.2.1 \
    && curl -fSL --output PowerShell.Linux.x64.$powershell_version.nupkg https://pwshtool.blob.core.windows.net/tool/$powershell_version/PowerShell.Linux.x64.$powershell_version.nupkg \
    && powershell_sha512='bfd0fac3fe5e905156d28433dbf4978d5cea69a4f1b63cb5b8d903f865f0febf4a1b0476a5b84a8e3509b354c44b0cd9e79b31a105176f03b90693ff51c7bb0b' \
    && echo "$powershell_sha512  PowerShell.Linux.x64.$powershell_version.nupkg" | sha512sum -c - \
    && mkdir -p /usr/share/powershell \
    && dotnet tool install --add-source / --tool-path /usr/share/powershell --version $powershell_version PowerShell.Linux.x64 \
    && dotnet nuget locals all --clear \
    && rm PowerShell.Linux.x64.$powershell_version.nupkg \
    && ln -s /usr/share/powershell/pwsh /usr/bin/pwsh \
    && chmod 755 /usr/share/powershell/pwsh \
    # To reduce image size, remove the copy nupkg that nuget keeps.
    && find /usr/share/powershell -print | grep -i '.*[.]nupkg$' | xargs rm

# my reproducer

FROM sdk-6.0.200 AS my-test

WORKDIR /app
RUN dotnet new webapp
RUN dotnet format -v diag --verify-no-changes

This reliably reproduces the issue and results in the errors:

Unhandled exception: System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
Could not load file or assembly 'Microsoft.CodeAnalysis.CSharp, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.
Could not load file or assembly 'Microsoft.CodeAnalysis, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.

I am unsure if this is actually a dotnet format problem or some kind of packaging issue of the SDK. In the second case, sorry for the noise 😇

[niemyjski]

Is there an eta for a fix on this? There are a lot of issues being opened and this seems like a blocking issue for many.

[jmarolf]

This will be fixed tin the 6.0.202 SDK release. I will leave this issue open until that release is downloadable.