dotnet-core/release-notes/5.0/5.0-known-issues.md

.NET 5 Known Issues

This document lists known issues for .NET 5 Preview 1 and beyond releases which may be encountered during usage.

.NET Runtime

Preview 1

1. Certain regular expressions involving negated character classes may fail to match correctly. This was a regression that occurred during extensive performance improvements made to the regular expression engine in 5.0. There is no general workaround, but modifying the expression may avoid the problem. This will be fixed in Preview 2. The issue dotnet/runtime #33399 explains the bug in detail.

2. Stepping with the debugger into code in certain assemblies in the .NET Platform may not succeed. This is because the assemblies do not have correct SourceLink information. This will be fixed in Preview 2. It is tracked by dotnet/runtime #33097.

3. The Microsoft.Windows.Compatibility package references dependencies that are not available at the targeted versions. To workaround, individually reference the packages your project needs. It is tracked by dotnet/runtime/issues #34351

Preview 2

1. The Microsoft.Windows.Compatibility package references dependencies that are not available at the targeted versions. To workaround, individually reference the packages your project needs. It is tracked by dotnet/runtime/issues #34351

Preview 6

1. With the work to provide sustainable and long-term support for WinRT consumption in .NET, the built-in support has been removed. This is a high impact change to all existing libraries and application that rely on the built-in WinRT support. The replacement for built-in WinRT support is the C#/WinRT tool chain. For complete details, see the official doc issue at dotnet/docs#18875.

ASP.NET Core Runtime

Preview 4

1. When running a docker enabled application from Visual Studio or running dotnet dev-certs https --trust -ep <<path.pfx>> -p <<password>> the HTTPS certificate created by ASP.NET Core will become corrupted and will prevent applications from running. If you try to run the dotnet dev-certs tool again it will think that there is no valid certificate and will try to recreate a new one every time it runs. To avoid this situation, you can add a global.json file at the root of your project and set it to use the latest 3.1.xxx installed sdk. If you tried to run the application within Visual Studio and it corrupted the certificate you will have to clean the existing certificates from your certificate store using the windows tooling. To do that, open the certificate manager (Windows+R -> mmc -> File -> Add remote add-in -> Certificates -> Current user -> Personal) and delete all the certificates that contain the "ASP.NET Core HTTPS development certificate" and also remove them from Trusted Root Certification Authorities We recommend to not create / open any docker-enabled projects while on Preview 4 SDK.

This will be fixed in the Preview 5 release. It is tracked by dotnet/aspnetcore/issues #21733

Preview 5

1. On Windows ARM64, NodeServices and SpaServices don’t work, because NodeJS is not supported on Windows ARM64. We will look into supporting these features once NodeJS releases support for Windows ARM64.

Preview 7

Some regular expressions will not match when using RegexOptions.Compiled and RegexOptions.IgnoreCase together

In some cases, a regular expression will fail to match when using RegexOptions.Compiled and RegexOptions.IgnoreCase together. This can occur when the pattern begins with a literal prefix (a sequence of characters that are not special regular expression tokens) whose last character is not affected by casing changes (for example, a symbol character).

The workaround is to remove "RegexOptions.Compiled", which will run a little slower but will avoid the bug. This problem is fixed in Preview 8. More details are in this issue: https://github.com/dotnet/runtime/issues/39518

Preview 8

Scaffolding

After installing Visual Studio 16.8 Preview 2, for ASP.NET Core projects targeting .NET 5 scaffolding will result in an error. The error that appears after attempting to use Add New Scaffolded Item is Install the package Microsoft.VisuaIStudio.Web.CodeGeneration.Design and try again.

Workaround:

The dotnet aspnet-codegenerator command line utility can be used. You can find more info on how to use the command line scaffolder at dotnet aspnet-codegenerator.

Templates

Known issue with the Azure B2C authentication web app password reset scenario not working.

Workaround:

Add the token cache implementation in startup.cs:

services.AddAuthentication(OpenIdConnectDefaults.AuthenticationScheme)
             .AddMicrosoftWebApp(Configuration, "AzureAdB2C")
             .AddMicrosoftWebAppCallsWebApi(Configuration, "AzureAdB2C")
             .AddInMemoryTokenCaches();

and then in appsettings.json, include a client secret.

Known issue with Register/Log in button not working when confirming email for a new user in Blazor Server apps with Individual User Accounts

Workaround:

Edit Areas\Identity\Pages\Shared_LoginPartial.cshtml in the project and change all instances of asp-area="MicrosoftIdentity" to asp-area="Identity"

- <a class="nav-link text-dark" asp-area="MicrosoftIdentity" asp-page="/Account/Register">Register</a>
+ <a class="nav-link text-dark" asp-area="Identity" asp-page="/Account/Register">Register</a>

.NET SDK

Preview 1

1. Runtime-dependent deployments of apps targeting .NET Core 3.1 that are created with .NET Core SDK 5.0.100 Preview 1 will require version 3.1.2 of the .NET Core runtime. This issue is tracked by dotnet/sdk #10812

Preview 5

1. For self-contained single-file apps, hostfxr and hostpolicy are not bundled into the application bundle, but are published alongside it. Framework-dependent single-file apps are not affected (since hostfxr and hostpolicy reside within the framework). This issue should be resolved in Preview 6, tracked by dotnet/runtime #32823.

Preview 8

1. (Fixed in RC1, affects only Preview 8 and RC1 before 5.0.100-rc.1.20451.10) Running xUnit tests fails to discover tests in with message No test is available in <assembly> Make sure that test discoverer & executors are registered and platform & framework version settings are appropriate and try again.. To solve this update your xunit.runner.visualstudio package to version 2.4.3. This version is used in dotnet new templates, but existing projects targetting, or updating to net5.0 need to be updated manually.

2. Projects targeting net5.0-windows will fail to build if the TargetPlatformMinimumVersion does not match the TargetPlatformVersion

   • An error similar to the following will be generated:

   NETSDK1005: Assets file 'C:\Users\username\source\repos\project\NuGetPackageExplorer-main\NuGetPackageExplorer-main\Types\obj\project.assets.json' doesn't have a target for 'net5.0-windows10.0.18362'. Ensure that restore has run and that you have included 'net5.0-windows10.0.18362' in the TargetFrameworks for your project.

3. C++/CLI

   • C++/CLI projects will not build if targeted to .NET 5.0

4. Warning icons in Dependencies node in Solution Explorer

   • For projects targeting .NET 5, warning icons may be displayed on packages listed in the Solution Explorer Depdendencies node