Hang in ConfidentialClientApplicationBuilderExtension.WithClientCredentials

[xs4free]

Microsoft.Identity.Web Library

Microsoft.Identity.Web.TokenAcquisition

Microsoft.Identity.Web version

2.15.3

Web app

Sign-in users and call web APIs

Web API

Protected web APIs (validating tokens)

Token cache serialization

In-memory caches

Description

In production the project that I'm currently working on, has experienced hangs on the sign-in proces of our Blazor Server website. We couldn't pinpoint the error in production, but I've found similar behaviour after starting the website locally a couple of times.
The code is hanging in ConfidentialClientApplicationBuilderExtension.WithClientCredentials on the line with

credentialsLoader.LoadCredentialsIfNeededAsync(credential, credentialSourceLoaderParameters).GetAwaiter().GetResult();

I've looked at the implementation of the potential credentials-loaders and found that the KeyVault-loader requires an async-path (maybe others as well).

I'm preparing a PR to make ConfidentialClientApplicationBuilderExtension.WithClientCredentialsAsync and the path upwards also async.

While making my change in the code I came across an obsolete message on ITokenAcquisition.ReplyForbiddenWithWwwAuthenticateHeader which pointed to Performance improvements and consequence on async methods in Microsoft.Identity.Web 1.9.0. So I suspect this bug has been in the code-base for a while.

Reproduction steps

Sorry, I'm not able to reproduce this consistently.

Error message

No error message, the application just halts and the browser shows a message that the server took to long to respond after a while.

Id Web logs

No response

Relevant code snippets

Sorry, I can't share the code of this application.

Regression

No response

Expected behavior

The call to ConfidentialClientApplicationBuilderExtension.WithClientCredentials to be fully async.

[jennyf19]

Included in 2.17.1 thanks @xs4free