Could not load file or assembly Microsoft.IdentityModel.Tokens (related to _FunctionsSkipCleanOutput)

[srmagura]

A newly-created Azure Functions project fails to load Microsoft.IdentityModel.Tokens even when the .csproj file contains a PackageReference to the Microsoft.IdentityModel.Tokens NuGet package.

Investigative information

N/A, this issue is reproducible locally.

Repro steps

1. Clone my repo: https://github.com/srmagura/FunctionsAssemblyLoadingRepro
2. Open the solution file in Visual Studio 2022.
3. Run the project.
4. Go to http://localhost:7071/api/Function1 in your web browser.

Expected behavior

There should be no errors in the debug window. The browser should display the text "Function executed."

Actual behavior

An error message is displayed in the debug window:

System.Private.CoreLib: Exception while executing function: Function1. FunctionsAssemblyLoadingRepro: Could not load file or assembly 'Microsoft.IdentityModel.Tokens, Version=6.14.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.

Known workarounds

Add <_FunctionsSkipCleanOutput>true</_FunctionsSkipCleanOutput> to the .csproj file. This is a workaround, not a solution, because this property is internal and undocumented.

Related issues

• _FunctionsSkipCleanOutput/FunctionsSkipCleanOutput/FunctionsPreservedDependencies are solutions to a problem created by the Functions team #7601
• [ExtensionsMetadataGenerator] Improve configuration for cleaning build output #5894
• Could not load file or assembly 'System.Text.Encoding.CodePages, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. #7061
• Could not load file or assembly 'System.IdentityModel.Tokens.Jwt, Version=5.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' after upgrading Azure Function's nuget packages to 3.0.4 or 3.0.5 #5756

[Ved2806]

Thank you for your feedback! We will check for the possibilities internally and update you with the findings.

[Cogax]

Similar: AzureAD/microsoft-identity-web#1428

[emriti]

Hi.. try lowering your azure function version, for example:

<Project Sdk="Microsoft.NET.Sdk"> <PropertyGroup> <TargetFramework>netcoreapp3.1</TargetFramework> <AzureFunctionsVersion>v3</AzureFunctionsVersion> </PropertyGroup> <ItemGroup> <PackageReference Include="Microsoft.IdentityModel.JsonWebTokens" Version="6.14.1" /> <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.14.1" /> <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="3.0.3" /> </ItemGroup> <ItemGroup> <None Update="host.json"> <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory> </None> <None Update="local.settings.json"> <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory> <CopyToPublishDirectory>Never</CopyToPublishDirectory> </None> </ItemGroup> </Project>

Btw, I have a similar problem when updating to a higher version of Azure Function.

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment.

[srmagura]

Hello @Ved2806, why did you mark this as "Needs: Author Feedback"? What feedback do you need from me? Thanks.

[Ved2806]

Hi @fabiocav, @brettsam Could you please look into this? We are able to repro this.