[CI][Windows] PowerShell bootstrap reports complete but pwsh.exe missing before tests

[dalexsoto]

Failure signature

Windows Integration Tests / Dotnet tests first runs Install PowerShell Core (log 200). It observed pwsh absent, reported MSI installation complete and updated PATH, yet the immediately following Undo Github merge PowerShell@2 task (log 201) failed with The term 'pwsh.exe' is not recognized as the name of a cmdlet, function, script file, or operable program. Prepare tests results and Html Report (log 230) repeated the error; .NET installation and actual tests were skipped. Stable signature: CI-infrastructure|WindowsIntegration|Install-PowerShell-Core-reports-complete|Undo-Github-merge|pwsh.exe-not-recognized-before-tests. Classification: shared Windows CI tooling/bootstrap failure; logs do not prove whether MSI installation or PATH propagation is the precise fault.

Confirmed occurrences

• #26730, head 7a91401cda9176471a41021aee69b02bfdd4257c: simulator run 15463868 / attempt 1 / Dotnet tests / Undo Github merge, log201, first failure 2026-09-25T17:04:41.079277Z.
• #26683, head 2fbdc937e9bf5d9e9d52ccd3631b33bf41c870b8: simulator run 15463857 / attempt 1 / Dotnet tests / Undo Github merge, log201, first failure 2026-09-25T17:07:45.479202Z.

Both use pipeline xamarin-macios-sim-pr-tests (definition 21922), Windows Integration stage attempt 1, job eac261bd-81a1-5958-df8d-94842fc987be attempt 1, task eaab6636-9cb5-52b3-7baf-9a8835ff506f. 2 confirmed occurrences across 2 distinct monitored PRs. First/latest observed failures were 17:04:41 / 17:07:45 UTC on 2026-09-25; both parent runs remain active. The identical installer-success/next-task-missing-binary/reporting-cascade sequence occurred on unrelated Maestro main and Rolf release branches, before any real Windows NUnit test.

Investigation, impact and current workaround

Compared Azure timelines, installer logs200, first failure logs201 and downstream logs230 for both runs. #26713's contemporaneous Windows job already had pwsh, successfully completed Undo Github merge, then separately failed HKLM registry setup (#26667). Searches across all open/closed dotnet/macios issues for the stable words, exact task, error fragment and PowerShell component found no matching root. Plausible candidates were inspected: #26537 records a NativeAOT test deadlock, #26490 NTSTATUS DLL-initialization/agent loss, #25313 SSH verification, #8585 logging and #26667 registry access denial. None is the same failure.

Restore/verify pwsh.exe installation and job PATH before PowerShell@2; an issue is not authorization for a source change or rerun. No monitor retry occurred: the parent runs are active, any later retry must rerun the whole Windows Integration Tests stage, and the all-actor 25-lifetime/10-head accepted-request budgets and safe CLI stage operation remain uncertified. No branch was edited. Real NUnit results and Helix items are unavailable because tests never started. Azure logs are retention-limited; no worker identifiers, IPs or credentials are disclosed.

AI-assisted CI monitoring.

[dalexsoto]

#26730: Windows PowerShell bootstrap path succeeded on external stage retry

The original #26730 failure on head 7a91401cda9176471a41021aee69b02bfdd4257c, Azure simulator run 15463868 / Windows Integration attempt 1, remains confirmed: Install PowerShell Core reported completion but the following Undo Github merge PowerShell@2 task could not find pwsh.exe, so product tests never started.

On an externally initiated whole Windows Integration Tests stage attempt 2, the exact Undo Github merge task (pipeline 21922, Dotnet tests job 9e1d9d57-f452-5f66-496f-9f10db70de3d attempt 2, task 97055a28-4804-52a5-cc91-563f0e851b42 record attempt 1, log 3071) succeeded. Its task log invoked C:\Program Files\PowerShell\7\pwsh.exe; Install PowerShell Core also succeeded (log 3070) and reported pwsh is already installed: 0, with no new MSI install shown. Local and remote Windows tests passed (logs 3094/3095); TestSummary-windows_integrationwindows-2 reports all 3 tests passed. The whole Windows stage attempt 2 succeeded at 2026-09-26 21:52:39 UTC, and parent run 15463868 completed succeeded at 21:57:33 UTC. #26730 merged at 21:57:48 UTC (merge bc0738d4f730d9fa09ce90e336059f858574403e). This confirms one retry outcome, not a monitor source fix or proof the prior MSI/PATH fault is permanently repaired.

The separate #26683 occurrence remains recorded; canonical failure totals stay at 2 occurrences across 2 distinct monitored PRs. The issue body has no Additional info to collect section. Original-run NUnit results remain unavailable because its tests never started; the passing attempt has the three-test summary. This is direct Azure CI, with no Helix work item. The monitor made no retry or source edit; external accepted-request actor/payload and exact PR/head lifetime counters remain uncertified. Azure artifacts are retention-limited, and no worker identifier or IP is disclosed.

AI-assisted CI monitoring update.

[dalexsoto]

Windows PowerShell bootstrap recurrence before product tests

Signature: CI-infrastructure|WindowsIntegration|Install-PowerShell-Core-reports-complete|Undo-Github-merge|pwsh.exe-not-recognized-before-tests. 3 confirmed exact-signature occurrences across 3 distinct monitored PRs; this batch adds 1 previously unprocessed occurrence(s).

• [release/11.0.1xx] [dotnet] Add DeployToDevice MSBuild target for 'dotnet run' support #26830 / 9891a344982fa33c3210122335b97051c1bfdbc9: run 15551721 / windows_integration / exact task, definition 21922, stage/job/task attempt 1, log 1390; 1 distinct record(s). Job eac261bd-81a1-5958-df8d-94842fc987be, task eaab6636-9cb5-52b3-7baf-9a8835ff506f.
  Exact scopes: Undo Github merge before product tests.

Diagnosis and collection:
Installer log 1389 observed pwsh absent, then reported MSI installation complete/PATH update. Next-task log 1390 could not resolve pwsh.exe; result-preparation log 1421 repeated the error. Product .NET tests never executed. This exactly matches the shared Windows tooling/bootstrap issue, not PR source. The precise MSI/PATH fault remains unisolated. No retry was sent: full all-actor counters and a verified existing-run entire Windows Integration Tests stage CLI payload are not certified; the parent run remains active.

Issue-specific checklist: the freshly read body has no Additional info to collect section; no requested diagnostic item is pending. Exact per-occurrence PR/head/run/definition/stage/job/task/attempt/log/test or configuration, timestamps where published, artifact/member identities and fingerprints are retained.
Unavailable/not established — MSI_vs_PATH_fault: Not isolated by installer-success/next-task-missing-executable evidence. Attributed scopes: #26830/run 15551721/job eac261bd-81a1-5958-df8d-94842fc987be.
Unavailable/not established — test_results: Unavailable because product tests never started. Attributed scopes: #26830/run 15551721/job eac261bd-81a1-5958-df8d-94842fc987be.
Unavailable/not established — safe_retry_operation: Verified stage-only existing-run CLI request shape unavailable; no retry was sent. Attributed scopes: #26830/run 15551721/job eac261bd-81a1-5958-df8d-94842fc987be.

No worker identifiers, machine addresses, credentials or raw environment blocks are published. No Helix item applies to these direct Azure jobs; diagnostics are retention-limited. No monitor source edit, binding/suppression change, retry or reopening.