main is red: `RunCommandFailFastAsync` used but undefined in TypeScriptEmptyAppHostTemplateTests (introduced by #17575)

[maddymontaquila]

Summary

main does not compile its CLI E2E test project, so ci.yml is failing on every PR (and on main itself). This blocks all PR merges until fixed.

Root cause

Commit 4cfc99df7 (PR #17575, "Fix TypeScript AppHost async callback deadlock") added tests/Aspire.Cli.EndToEnd.Tests/TypeScriptEmptyAppHostTemplateTests.cs, which calls a helper that does not exist:

tests/Aspire.Cli.EndToEnd.Tests/TypeScriptEmptyAppHostTemplateTests.cs(79): await auto.RunCommandFailFastAsync("cd TsDeadlockRepro", counter);
tests/Aspire.Cli.EndToEnd.Tests/TypeScriptEmptyAppHostTemplateTests.cs(80): await auto.RunCommandFailFastAsync("aspire restore --non-interactive", counter, TimeSpan.FromMinutes(3));
tests/Aspire.Cli.EndToEnd.Tests/TypeScriptEmptyAppHostTemplateTests.cs(81): await auto.RunCommandFailFastAsync("npm run build", counter, TimeSpan.FromMinutes(2));

Hex1bTerminalAutomator (from Hex1b.Automation) exposes RunCommandAsync, which is used everywhere else in the project, but there is no RunCommandFailFastAsync defined anywhere in the repo or the referenced package version. Build fails with:

error CS1061: 'Hex1bTerminalAutomator' does not contain a definition for 'RunCommandFailFastAsync'

Evidence

• ci.yml is failure on main HEAD 4cfc99df7 (and the prior commit), failing checks Stabilization Check and Tests / Setup for tests.
• git grep RunCommandFailFastAsync origin/main returns only the three call sites above — no definition.

Suggested fix

Either add the missing RunCommandFailFastAsync helper (a fail-fast variant of RunCommandAsync that asserts non-zero exit fails the test), bump the Hex1b package to a version that provides it, or replace the calls with the existing RunCommandAsync. Alternatively revert #17575 until the helper is available.

[maddymontaquila]

Confirmed this is now blocking PR CI repo-wide (not just main's own build). Example: PR #17680's Tests / Setup for tests job fails to compile with:

tests/Aspire.Cli.EndToEnd.Tests/TypeScriptEmptyAppHostTemplateTests.cs(79,24): error CS1061: 'Hex1bTerminalAutomator' does not contain a definition for 'RunCommandFailFastAsync'

On origin/main only RunCommandAsync exists (tests/Shared/Hex1bAutomatorTestHelpers.cs:265); there is no RunCommandFailFastAsync definition anywhere, and no open fix PR. Every PR whose CI merges with main is blocked until the missing helper is added (or #17575's test changes are reverted). cc the #17575 author to add the intended RunCommandFailFastAsync helper.

[joperezr]

🤖 Aspire triage pass — 2026-05-29 21:24 UTC

Area: area-engineering-systems (already applied)
Kind: test-failure (build break in CI; blocks PR merges)
Repro: yes-minimal — dotnet build tests/Aspire.Cli.EndToEnd.Tests/ reproduces error CS1061 on RunCommandFailFastAsync; details in the issue body and the comment from the reporter
Affected version(s): main HEAD (post-#17575 merge on 2026-05-29); not yet in a released bit
Severity: S2 — repo-wide PR CI failing (Tests / Setup for tests, Stabilization Check), no workaround other than reverting / patching main

Urgency: 🟡 vNext — recommend milestone 13.5
Reason: CI break on main introduced 2026-05-29 by #17575 (test-only file references a Hex1bTerminalAutomator.RunCommandFailFastAsync helper that does not exist in the repo or the referenced Hex1b.Automation version). Not a shipped-product regression in 13.4 (the failure is in the test project, not the 13.4 product surface), so it does not clear the 13.4 release-blocking bar as defined for this snap. However it is operationally urgent because it blocks landing any other 13.4 fixes in the final week before ship — flagging for human escalation so a release manager can decide whether to pull into 13.4 servicing (or just hotfix main and the release branch in parallel).

Suggested owner(s): @IEvangelist (author of the regressing PR #17575, score 5), backup @radical (score 9 on area-engineering-systems general activity)
Evidence:

• Fix TypeScript AppHost async callback deadlock #17575 ("Fix TypeScript AppHost async callback deadlock") merged by @IEvangelist 2026-05-29T19:24Z added tests/Aspire.Cli.EndToEnd.Tests/TypeScriptEmptyAppHostTemplateTests.cs containing the three undefined calls — direct authorship of the break
• @radical has the highest recency-weighted merged-PR count in area-engineering-systems over the last 90 days (e.g. Avoid empty test summary artifact URL #16478, Add LocalArchive + DotnetTool CLI install modes for E2E tests #16454, feat(ci): add test failure retry support to auto-rerun workflow #16446, Publish and sign CLI install scripts #15127, [CI] Fix randomly failing tests on azdo due to docker+testcontainers/ryuk issues #15111, Automatically rerun transient CI failures #15110, [CI] Update to newer linux image on internal pipeline #15055, Reduce the number of PR validation jobs #15031, Reduce PR validation time by decoupling CLI archive dependencies #15023, [release/13.2][CI] Use large runner for Aspire.Hosting.Tests #15016) — natural backup owner for the test-infra side
• CODEOWNERS not separately consulted — the regressing PR author is unambiguous here

Confidence: high (root cause + introducing commit are explicitly identified by the reporter and confirmed by the comment evidence; my own PR lookup confirms #17575 added the file 2026-05-29)
Needs human?: yes — repo-wide CI break in the final week before 13.4 ships; release manager needs to decide between (a) revert #17575, (b) add the missing RunCommandFailFastAsync helper, (c) swap calls to existing RunCommandAsync, or (d) bump Hex1b.Automation

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