[NSUrlSessionHandler] Surface cancelled requests with a better exception. Fixes #25667. by rolfbjarne · Pull Request #25699 · dotnet/macios

rolfbjarne · 2026-06-16T08:51:45Z

Add a test that sets up a stalling HTTP server, reads the first byte
successfully, then cancels the second ReadAsync via a caller-owned
CancellationToken.

TODO:

Implement the fix.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

🤖 Pull request created by Copilot

Fixes: #25667

…ion. Fixes #25667. Add a test: that sets up a stalling HTTP server, reads the first byte successfully, then cancels the second ReadAsync via a caller-owned CancellationToken. TODO: * Implement the fix. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…lation-test

rolfbjarne · 2026-06-16T12:50:45Z

/azp run

azure-pipelines · 2026-06-16T12:51:16Z

Azure Pipelines successfully started running 3 pipeline(s).

Localhost server access should be reliable, so there's no need to paper over failures with IgnoreInCI/Inconclusive. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

rolfbjarne · 2026-06-16T16:54:20Z

/azp run

azure-pipelines · 2026-06-16T16:54:51Z

Azure Pipelines successfully started running 3 pipeline(s).

With Content-Length set, HttpListener may buffer the output until all bytes are written. Switching to chunked transfer encoding ensures the first byte reaches the client immediately, so the first ReadAsync completes and the test can proceed to the cancellation scenario. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…stream-readasync-cancellation-test

rolfbjarne · 2026-06-17T10:57:24Z

/azp run

azure-pipelines · 2026-06-17T10:57:53Z

Azure Pipelines successfully started running 3 pipeline(s).

HttpListener buffers output even with chunked encoding, preventing the first byte from reaching the client in time. Using a raw TcpListener with NoDelay lets us write HTTP response bytes directly to the socket, ensuring the first chunk is delivered immediately so the test can proceed to the cancellation scenario. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Three changes to make the test work reliably: 1. Wait for the complete HTTP request (\r\n\r\n) before sending the response, to avoid confusing the HTTP framing. 2. Use Content-Length framing instead of chunked encoding, and send 4KB of body data (NSUrlSession may buffer very small payloads before calling DidReceiveData). 3. Declare a Content-Length 10x larger than the data actually sent, so the connection stays open and ReadAsync blocks in the polling loop waiting for more data. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

When the caller's CancellationToken triggers cancellation in the ReadAsync polling loop, rethrow as OperationCanceledException (via ThrowIfCancellationRequested) instead of wrapping it in TimeoutException. TimeoutException is now only thrown when the cancellation comes from an internal source (e.g. HttpClient.Timeout), not from the caller's token. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Use 'new OperationCanceledException(message, ex, cancellationToken)' instead of ThrowIfCancellationRequested so the original TaskCanceledException stack trace is preserved as InnerException. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

vs-mobiletools-engineering-service2 · 2026-06-18T17:09:25Z

✅ [PR Build #ff3034f] Build passed (Detect API changes) ✅

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Hash: ff3034fa3543c4c3e3979267211b43136c2b3f7d [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T17:19:30Z

✅ [PR Build #ff3034f] Build passed (Build packages) ✅

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Hash: ff3034fa3543c4c3e3979267211b43136c2b3f7d [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T17:21:45Z

✅ API diff for current PR / commit

NET (empty diffs)

iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

✅ API diff vs stable

NET (empty diffs)

iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

ℹ️ Generator diff

Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

Pipeline on Agent
Hash: ff3034fa3543c4c3e3979267211b43136c2b3f7d [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T17:30:37Z

✅ [PR Build #ff3034f] Build passed (Build macOS tests) ✅

Pipeline on Agent
Hash: ff3034fa3543c4c3e3979267211b43136c2b3f7d [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T19:04:59Z

🔥 [CI Build #ff3034f] Test results 🔥

Test results

❌ Tests failed on VSTS: test results

1 tests crashed, 25 tests failed, 168 tests passed.

Failures

❌ assembly-processing tests

🔥 Failed catastrophically on VSTS: test results - assembly-processing (no summary found).

Html Report (VSDrops) Download

❌ introspection tests

4 tests failed, 2 tests passed.

Failed tests

introspection/iOS - simulator/Debug: LaunchTimedOut
introspection/iOS - simulator/Debug (ARM64): LaunchTimedOut
introspection/tvOS - simulator/Debug: LaunchTimedOut
introspection/tvOS - simulator/Debug (ARM64): LaunchTimedOut

Html Report (VSDrops) Download

❌ monotouch tests (macOS)

1 tests failed, 22 tests passed.

Failed tests

monotouch-test/macOS/Release (static registrar, all optimizations): TimedOut (Execution timed out after 1200 seconds.
Test run crashed)

Html Report (VSDrops) Download

❌ monotouch tests (tvOS)

20 tests failed, 0 tests passed.

Failed tests

monotouch-test/tvOS - simulator/Debug: LaunchTimedOut
monotouch-test/tvOS - simulator/Release (link sdk): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (link all): LaunchTimedOut
monotouch-test/tvOS - simulator/Debug (LinkSdk): LaunchTimedOut
monotouch-test/tvOS - simulator/Debug (static registrar): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (all optimizations): LaunchTimedOut
monotouch-test/tvOS - simulator/Debug (ARM64): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (NativeAOT, ARM64): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (trimmable static registrar, NativeAOT, ARM64): LaunchTimedOut
monotouch-test/tvOS - simulator/Debug (managed static registrar): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (managed static registrar, all optimizations): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (NativeAOT, x64): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (trimmable static registrar, NativeAOT, x64): LaunchTimedOut
monotouch-test/tvOS - simulator/Debug (interpreter): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (interpreter): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (compat inline Class.GetHandle): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (strict inline Class.GetHandle): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (compat inline dlfcn): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (strict inline dlfcn, link sdk): LaunchTimedOut
monotouch-test/tvOS - simulator/Release (NativeAOT, .NET 11 defaults): LaunchTimedOut

Html Report (VSDrops) Download

Successes

✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (iOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (MacCatalyst): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (macOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (Multiple platforms): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (tvOS): All 1 tests passed. Html Report (VSDrops) Download
✅ framework: All 2 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 4 tests passed. Html Report (VSDrops) Download
✅ generator: All 5 tests passed. Html Report (VSDrops) Download
✅ interdependent-binding-projects: All 4 tests passed. Html Report (VSDrops) Download
✅ linker (iOS): All 11 tests passed. Html Report (VSDrops) Download
✅ linker (MacCatalyst): All 11 tests passed. Html Report (VSDrops) Download
✅ linker (macOS): All 11 tests passed. Html Report (VSDrops) Download
✅ linker (tvOS): All 11 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 20 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 23 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ sharpie: All 1 tests passed. Html Report (VSDrops) Download
✅ windows: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 4 tests passed. Html Report (VSDrops) Download
✅ xtro: All 1 tests passed. Html Report (VSDrops) Download

macOS tests

✅ Tests on macOS Monterey (12): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Ventura (13): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Sonoma (14): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Sequoia (15): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Tahoe (26): All 5 tests passed. Html Report (VSDrops) Download

Linux Build Verification

✅ Linux build succeeded

Pipeline on Agent
Hash: ff3034fa3543c4c3e3979267211b43136c2b3f7d [PR build]

rolfbjarne added the copilot label Jun 16, 2026

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Merge branch 'main' into dev/rolf/issue-25667-stream-readasync-cancel…

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…lation-test

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Don't ignore test failures in CI

03840d1

Localhost server access should be reliable, so there's no need to paper over failures with IgnoreInCI/Inconclusive. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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rolfbjarne and others added 2 commits June 17, 2026 08:49

Merge remote-tracking branch 'origin/main' into dev/rolf/issue-25667-…

292dda8

…stream-readasync-cancellation-test

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vs-mobiletools-engineering-service2 commented Jun 18, 2026

✅ [PR Build #ff3034f] Build passed (Detect API changes) ✅

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✅ [PR Build #ff3034f] Build passed (Build packages) ✅

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✅ API diff vs stable

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✅ [PR Build #ff3034f] Build passed (Build macOS tests) ✅

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🔥 [CI Build #ff3034f] Test results 🔥

Test results

Failures

❌ assembly-processing tests

❌ introspection tests

Failed tests

❌ monotouch tests (macOS)

Failed tests

❌ monotouch tests (tvOS)

Failed tests

Successes

macOS tests

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