Exception thrown by SocketsHttpHandler has changed

[mconnew]

Description

When a hostname can't be found, WCF throws System.ServiceModel.EndpointNotFoundException when HttpClient.SendAsync throws a specific exception. The details of the exception have now changed. Previously the exception thrown was System.Net.Http.HttpRequestException with an inner exception of type System.Net.Sockets.SocketException. If the value of SocketException.SocketErrorCode is one of SocketError.TryAgain, SocketError.NoRecovery, SocketError.NoData, or SocketError.HostNotFound, we will throw System.ServiceModel.EndpointNotFoundException.

On a recent test run, there's a new exception class between HttpRequestException and SocketException. The exception now looks like this:

-------- System.Net.Http.HttpRequestException : No such host is known. (nonexisthost:80)
------------ System.Net.NetworkException : No such host is known.
---------------- System.Net.Sockets.SocketException : nodename nor servname provided, or not known

There is now an additional NetworkException in the exception hierarchy.

Configuration

.NET Version: .NET 5.0.100-rc.1.20452.10
OS Version: So far I have seen this on OSX and on Windows 10 so this isn't OS specific

Regression?

This is new different behavior in .NET 5 so it is a regression.

[ghost]

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[geoffkizer]

This change got reverted. You should see the old exception behavior here in recent RC2 builds.

That said, it would be much better if you didn't have to rely on inner exceptions here. We've talked about having something like HttpRequestErrorCode on HttpRequestMessage; if we had that, presumably there would be a code like HostNotFound and you could check for that. Not sure if we have an issue on this currently...

[mconnew]

You mean like I requested in #15567 5 years ago before, 8 months before .NET Core 1.0 was released? The problem I now have is WCF is still only targeting netstandard2.0. This is because our package is still supported on .NET Framework which stopped at netstandard2.0. I can't access any new api's unless they are exposed in a nuget package which supports netstandard2.0.

[geoffkizer]

You mean like I requested in #15567 5 years ago before, 8 months before .NET Core 1.0 was released?

Yep, exactly :) Thanks for finding that issue.

[mconnew]

I've confirmed it's fixed in a more recent build. Closing the issue.