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Fix NotSupportedException in DnsSocket.ReceiveAsync peek overload on macOS - #134924
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…macOS UnsafeAccessorType cannot represent value-type parameters, but the SocketFlags-taking ReceiveAsync overload declared its flags parameter with [UnsafeAccessorType], which threw NotSupportedException at runtime and broke every async DNS query on macOS (the OSX resolver uses this overload to await readiness on the mDNSResponder socket fd). Invoke that overload via reflection instead, mirroring the existing workaround used for the Socket constructor's value-type enum parameters. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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/azp run runtime-libraries-coreclr outerloop |
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Tagging subscribers to this area: @karelz, @dotnet/ncl |
cincuranet
approved these changes
Sep 30, 2026
MihaZupan
approved these changes
Sep 30, 2026
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Description
The macOS
DnsResolverimplementation (DnsResolverPal.OSX.cs) awaits readiness on the mDNSResponder connection's socket file descriptor by callingDnsSocket.ReceiveAsync(buffer, peek: true, cancellationToken). That overload forwards toSocket.ReceiveAsync(Memory<byte>, SocketFlags, CancellationToken)via an[UnsafeAccessor]-decorated method whoseflagsparameter was typed with[UnsafeAccessorType("System.Net.Sockets.SocketFlags, System.Net.Sockets")].UnsafeAccessorTypecannot represent value types (see the existing comment/workaround already applied to theSocketconstructor'sSocketType/ProtocolTypeenum parameters in the same file). BecauseSocketFlagsis an enum, this threwSystem.NotSupportedException: ValueTypes are not supported with UnsafeAccessorTypeAttributeat runtime on every call — breaking every async DNS query path on macOS.This was visible in CI as widespread
System.Net.NameResolution.Functional.Testsfailures on macOS outer-loop runs, e.g.:Fix
Apply the same reflection-based workaround already used for the
Socketconstructor: cache aMethodInfofor theSocketFlags-takingReceiveAsyncoverload and invoke it viaMethodInfo.Invoke, instead of declaring it through[UnsafeAccessor]/[UnsafeAccessorType].Testing
Ran the full macOS outer-loop
System.Net.NameResolution.Functional.Testssuite (DnsResolverTest, sync and async variants) locally on macOS/arm64:Prior to the fix, every async test case failed with the
NotSupportedExceptionabove.Note
This PR description and commit were AI-generated with GitHub Copilot CLI.