[CI] Flaky: HarnessException "Unable to evaluate the property OutputPath" (exit code 139)

[rolfbjarne]

Flaky Test Report (automated)

Test: xharness AppBundleLocator.GetPropertyByMSBuildEvaluationAsync — MSBuild property evaluation crashes
Platform: macOS, Mac Catalyst
Category: Flaky / Infrastructure
Period: June 22–29, 2026

Occurrence Summary

PR	Build	Configuration	Bot	Direct Link
#25713	14515144	link all/macOS/Debug (PrepareAssemblies, CoreCLR, Trimmable Static Registrar)	AcesShared 9	Run tests
#25849	14515024	trimmode link/Mac Catalyst/Release	AcesShared 81	Run tests

Total: Failed in 2 builds across 2 unrelated PRs.

Error Details

Both failures share the same pattern — the MSBuild property evaluation subprocess crashes with exit code 139 (SIGSEGV — segmentation fault). This prevents xharness from locating the app bundle and the entire test configuration fails:

Build 14515144 (PR#25713):

HarnessException: Unable to evaluate the property OutputPath in
/Users/cloudtest/vss/_work/1/s/macios/tests/xharness/bin/Debug/tmp-test-dir/link all474/link all.csproj,
build failed with exit code 139. Timed out: False
   at Xharness.AppBundleLocator.GetPropertyByMSBuildEvaluationAsync(...)
   at Xharness.AppBundleLocator.LocateAppBundle(...)
   at Xharness.Jenkins.TestTasks.MacExecuteTask.RunTestAsync()

Build 14515024 (PR#25849):

HarnessException: Unable to evaluate the property OutputPath in
/Users/cloudtest/vss/_work/1/s/macios/tests/xharness/bin/Debug/tmp-test-dir/trimmode link94/trimmode link.csproj,
build failed with exit code 139. Timed out: False
   at Xharness.AppBundleLocator.GetPropertyByMSBuildEvaluationAsync(...)
   at Xharness.AppBundleLocator.LocateAppBundle(...)
   at Xharness.Jenkins.TestTasks.MacExecuteTask.RunTestAsync()

Analysis

• Exit code 139 = SIGSEGV — the dotnet process that evaluates MSBuild properties is crashing with a segmentation fault.
• Both occurrences are on AcesShared pool bots (9 and 81), suggesting this may be related to the bot environment (e.g., corrupted dotnet install, missing shared libraries, or memory issues on these VMs).
• The failures are in different test suites (link all on macOS and trimmode link on MacCatalyst) but both hit the same code path (AppBundleLocator.GetPropertyByMSBuildEvaluationAsync).
• This is likely a transient infrastructure issue on AcesShared bots rather than a code bug.

Classification

This failure was identified as flaky/infrastructure because:

• It appeared across 2 unrelated PRs ([msbuild] Resolve Content and BundleResource items using the main project's location. Fixes 23898. #25713, [build] Fix NuGet migration race condition workaround #25849)
• The crash (SIGSEGV) in a dotnet subprocess is not caused by test code
• Both occurrences are on AcesShared pool bots

---

This issue was automatically generated by CI post-mortem analysis.

[dalexsoto]

Reopening because the same dotnet build -getProperty:OutputPath SIGSEGV recurred after the fix in #25862, on two monitored PR heads that both contain merge commit 9f5295776c545e9a5041167736d19c6d6d79e436:

PR / head	Build attempt / job	Evidence
#26140 / 5ebeaab0ae976b54831f68aa059217bb9ce4c49e	14745481 attempt 1 — monotouch_tvos / Run tests	OutputPath evaluation exited 139 on AcesShared 36. PR is conflicting, so no retry.
#26281 / 3f68b464d8acbbcee96c586f04f93bc07e4747ec	14753858 attempt 1 — linker_tvos / Run tests	15 tvOS configurations failed through the same AppBundleLocator.GetPropertyByMSBuildEvaluationAsync path on AcesShared 2. The published CrashReports container has no linker_tvos report, so the native stack is unavailable. Build remains active; no retry yet.

The canonical signature now covers 4 build/job occurrences across 4 PRs. These builds postdate the June 30 closure by more than two weeks and incorporate the closing fix, so the new evidence invalidates the completed closure state.

[dalexsoto]

Retry outcome for #26281 @ 3f68b464d8acbbcee96c586f04f93bc07e4747ec: build 14753858 simulator_tests attempt 2 cleared the original linker_tvos OutputPath/exit-139 failure.

The overall retry remained failed because a previously canceled, independently classified monotouch_macos NativeAOT configuration exposed a source issue: SFChooseIdentityTableCellView is available through objc_getClass, but its Objective-C class symbol is absent from SecurityInterface.tbd. That source issue is fixed on the PR branch by commit c0556e2b1e91419b677890bde8fbade3277d196f; fresh CI is starting.

Retry budget usage is 1 lifetime / 1 old-head request. The OutputPath recurrence count remains 4 build/job occurrences across 4 PRs.

[dalexsoto]

New exact-signature occurrence on PR #26500 @ f21c4957124500591af17e944b0c1775c2d51982:

• Build 15162528 / T: linker_tvos / Run tests reproduced AppBundleLocator.GetPropertyByMSBuildEvaluationAsync evaluating OutputPath with target _GenerateBundleName, where the host dotnet build process exited 139 and TimedOut=False.
• The trigger was trimmode link/tvOS - simulator/Debug. Its app build had already succeeded; the crash occurred during the subsequent property probe. The aggregate harness attached the same exception to 15 configurations, which are cascades rather than 15 independent roots.
• Classification remains a known intermittent host dotnet/MSBuild property-evaluation SIGSEGV. The XHarness dependency update contains no implementation change matching this path.
• The native .ips report was written under /Library/Logs/DiagnosticReports, while the pipeline collector checked the user crash directory, so the native faulting stack is unavailable in published artifacts.

The canonical total is now 5 build/job occurrences across 5 distinct monitored PRs. Build 15162528 remains active, so no retry was submitted. Retry accounting is 3 PR-lifetime / 0 current-head requests.

Issue-specific checklist: none; the issue body has no Additional info to collect section.

[dalexsoto]

Terminal outcome for PR #26500 @ f21c4957124500591af17e944b0c1775c2d51982:

• Build 15162528 completed failed at 2026-09-01T04:56:55Z.
• The linker_tvos OutputPath/exit-139 occurrence remains the single root for this signature; its 15 harness results are cascades.
• No retry was submitted because the same build also has a deterministic recurring Ventura worker hang that guarantees another unchanged run is not diagnostically useful.

The canonical count remains 5 build/job occurrences across 5 distinct monitored PRs. Retry accounting for PR #26500 is 3 lifetime / 0 current-head requests.

Issue-specific checklist: none; the issue body has no Additional info to collect section.

[dalexsoto]

Successful retry outcome for PR #26500 @ f21c4957124500591af17e944b0c1775c2d51982:

• Build 15162528, simulator_tests attempt 2 / linker_tvos completed successfully on AcesShared 1 at 2026-09-01T09:03:15Z.
• The original AppBundleLocator.GetPropertyByMSBuildEvaluationAsync OutputPath/exit-139 failure did not recur. The entire simulator stage completed succeeded at 09:03:28Z.
• The overall build completed failed at 09:08:12Z only because the separately tracked Ventura macOS/osx-arm64 monotouch-test timeout in [CI] Flaky: monotouch-test macOS NativeAOT configurations TimedOut #25687 remained failed.

The canonical count remains 5 build/job occurrences across 5 distinct monitored PRs. Attempt 2 was the fourth PR-lifetime and first current-head retry request; a subsequent Ventura-only retry is active, so current accounting is 5 lifetime / 2 current-head requests.

Issue-specific checklist: none; the issue body has no Additional info to collect section.

[dalexsoto]

New exact-signature occurrence on PR #26526 @ 9460728d5943096ee89d7a53b83f584aeb34a8f8:

• Build 15180780 / T: monotouch_tvos / Run tests failed on AcesShared 40.
• AppBundleLocator.GetPropertyByMSBuildEvaluationAsync could not evaluate OutputPath because the host dotnet build process exited 139 with TimedOut=False.
• The aggregate harness attached the same exception to 19 tvOS configurations. These are cascades from one property-evaluation process crash, not 19 independent root occurrences.
• Classification remains a known intermittent host dotnet/MSBuild property-evaluation SIGSEGV. The PR changes test CodeQL suppressions and does not modify this path.
• Build 15180780 remains active, so no retry is permitted yet.

The durable ledger was reconciled against the retained issue body and comments before this update. The canonical total is now 6 build/job occurrences across 6 distinct monitored PRs.

The issue body has no Additional info to collect checklist.

[dalexsoto]

Active retry status for PR #26526 @ 9460728d5943096ee89d7a53b83f584aeb34a8f8:

• After refreshing the unchanged mergeable head, terminal build, failed scope, observable attempts, and retry budgets, Azure accepted build 15180780, simulator_tests attempt 2.
• Only monotouch_tvos is rerunning, on AcesShared 12.
• Retry usage is 1 PR-lifetime / 1 current-head request.
• No equivalent retry will be submitted while attempt 2 is active.

The canonical count remains 6 build/job occurrences across 6 PRs pending the retry outcome. The issue body has no Additional info to collect checklist.