QuicConnection.ConnectAsync raises SocketException when host not found

[bentoi]

Description

The QuicConnect.ConnectAsync method raises a SocketException(SocketErrorCode = HostNotFound) if the resolution of a DnsEndPoint set with QuicClientOptions.RemoteEndpoint fails. I did expect a QuicException with a suitable error code instead.

Reproduction Steps

await using var connection = await QuicConnection.ConnectAsync(new QuicClientConnectionOptions
    {
          RemoteEndPoint = new DnsEndPoint("bogus.foo.com", 5001);
          ClientAuthenticationOptions = new SslClientAuthenticationOptions { ... } 
    });

Expected behavior

A QuicException with suitable QuicError.

Actual behavior

It raises a SocketException.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

[ghost]

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Issue Details

---

Description

The QuicConnect.ConnectAsync method raises a SocketException(SocketErrorCode = HostNotFound) if the resolution of a DnsEndPoint set with QuicClientOptions.RemoteEndpoint fails. I did expect a QuicException with a suitable error code instead.

Reproduction Steps

await using var connection = await QuicConnection.ConnectAsync(new QuicClientConnectionOptions
    {
          RemoteEndPoint = new DnsEndPoint("bogus.foo.com", 5001);
          ClientAuthenticationOptions = new SslClientAuthenticationOptions { ... } 
    });

Expected behavior

A QuicException with suitable QuicError.

Actual behavior

It raises a SocketException.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	bentoi
Assignees:	-
Labels:	area-System.Net.Quic
Milestone:	-

[ManickaP]

We have several places where we don't raise QuicException. Some raise AuthenticationException for example. However, it might be unexpected to get SocketException, seemingly System.Net.Sockets exclusive type, from System.Net.Quic.
On the other hand, in #76435 we got a feedback that we could leverage SocketException, albeit as a wrapped exception.
Lastly, in #75184, we have another use case that expects us to always wrap in QuicException.

Either way, we have several loosely related issue to exception types and their wrapping. We should take all this feedback and come up with a comprehensive solution to this.

Triage: this should be settled in 8.0.

cc: @rzikm

[wfurt]

It seems like we don't document what ConnectAsync can throw. We should probably fix that regardless of the choice so callers can handle that properly.

[alexrp]

It seems like we don't document what ConnectAsync can throw.

Just for the record, that seems to be a pervasive issue with all the QUIC API documentation, not just this particular method.

[antonfirsov]

Note that we shouldn't document stored (async) exceptions in the exception section of the API docs - dotnet/dotnet-api-docs#7840 (comment). The fact that we do it for some of the networking API docs is a violation of general BCL API doc practices.

[alexrp]

Note that we shouldn't document stored (async) exceptions in the exception section of the API docs - dotnet/dotnet-api-docs#7840 (comment). The fact that we do it for some of the networking API docs is a violation of general BCL API doc practices.

That issue mentions that async APIs should point to sync APIs for the possible exceptions. There are no sync APIs for QUIC at this time, though?

[antonfirsov]

Yepp, just pointed it out in the discussion.

[ManickaP]

Triage: this is part of bigger revision on exception in Quic. We should address this 8.0.

Slightly related: #75184

[wfurt]

We agreed to throw SocketException for transport errors - part of #82262 and based on API review feedback.

e.g. QuicExecption will indicate erros at Quic layer, SocketException with indicate problems bellow - e.g. IP or UDP. We shall document that somehow, perhaps as remarks because of pending debate about exceptions thrown synchronously vs exceptions stored in resulting Task.

[ManickaP]

Closing this in lieu of #92943