CopyToAsync_AllDataCopied fails on macOS 15: MemberData not found on inherited class

[rzikm]

Note

This issue was created with the assistance of AI (GitHub Copilot).

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1388505
Build error leg or test failing: System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
Helix log: https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-5a4f2044519842698e/System.Net.Sockets.Tests/3/console.1f596a8f.log?helixlogtype=result

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": "Could not find public static member (property, field, or method) named 'CopyToAsync_AllDataCopied_MemberData' on System.Net",
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Description

NetworkStreamTest.CopyToAsync_AllDataCopied has been failing consistently on macOS 15 (both amd64 and arm64) since April 7, 2026. The test uses [MemberData(nameof(CopyToAsync_AllDataCopied_MemberData))] to get test data from an inherited static method in the base class ConnectedStreamConformanceTests (in StreamConformanceTests.cs).

The error is:

System.ArgumentException : Could not find public static member (property, field, or method) named 'CopyToAsync_AllDataCopied_MemberData' on System.Net.Sockets.Tests.NetworkStreamTest

The CopyToAsync_AllDataCopied_MemberData method exists on the base class ConnectedStreamConformanceTests and is public static. The test works on all other platforms. This appears to be a test infrastructure / xunit reflection issue specific to macOS 15.

Frequency: 10 distinct builds over 2 weeks (April 7ΓÇô21), macOS 15 only.
Platforms affected: OSX.15.Amd64.Open, OSX.15.Arm64.Open

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1388505
Result validation: ⚠️ Validation could not be done without an Azure DevOps build URL on the issue. Please add it to the "Build: 🔎" line.
Validation performed at: 4/21/2026 2:33:24 PM UTC

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1388505
Error message validated: [Could not find public static member (property, field, or method) named 'CopyToAsync_AllDataCopied_MemberData' on System.Net]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 4/21/2026 2:35:17 PM UTC

Report

Build	Repository	Test	Pull Request
1460723	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
1459621	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#129226
1459328	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#125437
1458940	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
1457553	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#125437
1457550	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#129226
1457058	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
1455810	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#127498
1455366	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
1453379	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1452872	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1452386	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
1450787	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1449088	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
1447125	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1446635	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1444966	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1442805	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1442382	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1441846	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1440990	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution	#128408
1440694	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#127498
1440191	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1439314	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution	#128705
1439078	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#125437
1438268	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1436493	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1436708	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution	#128586
1435940	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#128448
1434964	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1434095	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#128448
1433744	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1433143	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1432621	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied
1431552	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#128408
1431370	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#125437
1430925	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1429871	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#125437
1429699	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#128408
1429323	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1428144	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution	#125437
1427748	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#124173
1427615	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1427030	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#125437
1426342	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution	#125437
1426173	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#128284
1425947	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution
1424920	dotnet/runtime	System.Net.Sockets.Tests.NetworkStreamTest.CopyToAsync_AllDataCopied	#128068
1420407	dotnet/runtime	System.Net.Sockets.Tests.WorkItemExecution	#128135

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
4	12	49

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Tagging subscribers to 'os-maccatalyst': @vitek-karas, @kotlarmilos, @steveisok, @akoeplinger
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