Forward StatusCode to HttpRequestException whenever possible

[Copilot]

This PR forwards HTTP status codes to HttpRequestException in three locations where they were previously not being included, following up on #105610 & #105546.

Changes Made

1. HttpConnectionPool.cs (line 522): When throwing VersionNegotiationError due to version policy restrictions, now forwards the StatusCode from the inner HttpRequestException that triggered the retry.

2. HttpConnection.cs (line 2080): When throwing UserAuthenticationError due to connection close during response draining, now forwards the StatusCode from the HttpResponseMessage.

3. HttpConnection.cs (line 2096): When throwing UserAuthenticationError due to failed response draining, now forwards the StatusCode from the HttpResponseMessage.

Example

Before this change, these exceptions would not include status code information:

// Version negotiation error - no status code preserved
throw new HttpRequestException(HttpRequestError.VersionNegotiationError, message, innerException);

// Authentication error - no status code from response
throw new HttpRequestException(HttpRequestError.UserAuthenticationError, message);

After this change, status codes are properly forwarded:

// Version negotiation error - preserves status code from inner exception
throw new HttpRequestException(HttpRequestError.VersionNegotiationError, message, innerException, innerException.StatusCode);

// Authentication error - includes status code from response
throw new HttpRequestException(HttpRequestError.UserAuthenticationError, message, statusCode: response.StatusCode);

This provides better diagnostic information to callers who can now access the HTTP status code that caused the underlying failure.

Testing

• All existing System.Net.Http unit tests pass (952 test cases, 0 failures)
• Builds successfully with no warnings or errors
• Manual verification confirms status codes are properly forwarded

Fixes #105700.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

• badhost
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile System.Net.Http.Functional.Tests.deps.json /home/REDACTED/.nuget/packages/microsoft.dotnet.xunitconsoleREDACTED/2.9.2-beta.25260.104/build/../tools/net/xunit.console.dll System.Net.Http.Functional.Tests.dll -xml testResults.xml -nologo -notrait category=OuterLoop -notrait category=failing (dns block)
• does.not.exist.sorry
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.deps.json /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/Microsoft.DotNet.RemoteExecutor.dll System.Net.Http.Functional.Tests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 System.Net.Http.Functional.Tests.DiagnosticsTest <SendAsync_ConnectionFailure_RecordsActivitiesWithCorrectErrorInfo>g__RunTest|18_0 /tmp/delryg3w.4s2 1.1 False dns (dns block)
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.deps.json /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/Microsoft.DotNet.RemoteExecutor.dll System.Net.Http.Functional.Tests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 System.Net.Http.Functional.Tests.DiagnosticsTest <SendAsync_ConnectionFailure_RecordsActivitiesWithCorrectErrorInfo>g__RunTest|18_0 /tmp/3iguzv2q.i3r 1.1 True dns (dns block)
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.deps.json /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/Microsoft.DotNet.RemoteExecutor.dll System.Net.Http.Functional.Tests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 System.Net.Http.Functional.Tests.DiagnosticsTest <SendAsync_ConnectionFailure_RecordsActivitiesWithCorrectErrorInfo>g__RunTest|18_0 /tmp/gmfbd2cq.feu 2.0 True dns (dns block)
• nosuchhost.invalid
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile System.Net.Http.Functional.Tests.deps.json /home/REDACTED/.nuget/packages/microsoft.dotnet.xunitconsoleREDACTED/2.9.2-beta.25260.104/build/../tools/net/xunit.console.dll System.Net.Http.Functional.Tests.dll -xml testResults.xml -nologo -notrait category=OuterLoop -notrait category=failing (dns block)
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.deps.json /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/Microsoft.DotNet.RemoteExecutor.dll System.Net.Http.Functional.Tests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 System.Net.Http.Functional.Tests.DiagnosticsTest+<>c <SendAsync_ExpectedDiagnosticExceptionActivityLogging>b__23_0 /tmp/bn1qqsgk.chn 2.0 True (dns block)
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.deps.json /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/Microsoft.DotNet.RemoteExecutor.dll System.Net.Http.Functional.Tests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 System.Net.Http.Functional.Tests.DiagnosticsTest+<>c <SendAsync_ExpectedDiagnosticExceptionActivityLogging>b__23_0 /tmp/3nuqi3xb.doc 1.1 False (dns block)
• www.microsoft.com
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/System.Net.Http.Functional.Tests.deps.json /home/REDACTED/work/runtime/runtime/artifacts/bin/System.Net.Http.Functional.Tests/Debug/net10.0-linux/Microsoft.DotNet.RemoteExecutor.dll System.Net.Http.Functional.Tests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 System.Net.Http.Functional.Tests.HttpClientHandler_ServerCertificates_Test+<>c <HttpClientUsesSslCertEnvironmentVariables>b__26_0 /tmp/2tawtdzz.cvv 1.1 True (dns block)
• www.some.example
  • Triggering command: /home/REDACTED/work/runtime/runtime/artifacts/bin/testhost/net10.0-linux-Debug-x64/dotnet exec --runtimeconfig System.Net.Http.Functional.Tests.runtimeconfig.json --depsfile System.Net.Http.Functional.Tests.deps.json /home/REDACTED/.nuget/packages/microsoft.dotnet.xunitconsoleREDACTED/2.9.2-beta.25260.104/build/../tools/net/xunit.console.dll System.Net.Http.Functional.Tests.dll -xml testResults.xml -nologo -notrait category=OuterLoop -notrait category=failing (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to my firewall allow list

---

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[dotnet-policy-service]

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

[MihaZupan]

Are these the only 3 cases of the status code not being propagated to exceptions?
The issue called out these 3, but there might be more.

[Copilot]

Are these the only 3 cases of the status code not being propagated to exceptions?
The issue called out these 3, but there might be more.

After conducting a comprehensive search through the System.Net.Http codebase, these appear to be the only 3 cases where status codes weren't being propagated to HttpRequestException when they should have been.

I systematically examined all files that throw HttpRequestException and checked for:

1. Cases where HttpResponseMessage.StatusCode is available but not forwarded
2. Cases where an inner HttpRequestException.StatusCode could be forwarded
3. Catch-and-rethrow scenarios

The other similar patterns I found are already handled correctly:

• HttpConnectionPool.cs proxy tunnel errors already forward tunnelResponse.StatusCode
• HttpResponseMessage.EnsureSuccessStatusCode() already forwards _statusCode
• Authentication helpers use appropriate status codes (e.g., HttpStatusCode.Unauthorized)
• Catch-and-rethrow cases either use bare throw; or ExceptionDispatchInfo.Throw() which preserve the original exception

So the 3 locations identified in issue #105700 appear to be the complete set of missing cases.

[antonfirsov]

Note that when I opened #105700, I was just looking at code patterns without investing time to analyze how realistic it is to hit actual practical cases of missing a status code that could be present.

This is only a good issue for copilot if we are fine fixing the code so it has the right pattern, but without looking deeper and trying to understand/test the scenarios.

[49016]

Leaving that catch block completely empty seems wrong; since this should trigger an error, shouldn't we assert that we got here?

[dotnet-policy-service]

Draft Pull Request was automatically closed for 30 days of inactivity. Please let us know if you'd like to reopen it.