[ci-scan] Test failure: AssemblyTests.AssemblyLoadWithPublicKey (iossimulator-arm64)

[github-actions]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1452872
Build error leg or test failing: iossimulator-arm64 Release AllSubsets_CoreCLR - System.Reflection.Tests

Error Details

Two tests in System.Reflection.Tests.AssemblyTests consistently fail on iossimulator-arm64 CoreCLR:

[FAIL] System.Reflection.Tests.AssemblyTests.AssemblyLoadWithPublicKey
System.IO.FileNotFoundException : Could not load file or assembly 'System.Runtime, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
   at System.Reflection.RuntimeAssembly.InternalLoad(AssemblyName assemblyName, StackCrawlMark& stackMark, AssemblyLoadContext assemblyLoadContext, RuntimeAssembly requestingAssembly, Boolean throwOnFileNotFound)
   at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
   at System.Reflection.Tests.AssemblyTests.AssemblyLoadWithPublicKey()

[FAIL] System.Reflection.Tests.AssemblyTests.AssemblyGetForwardedTypesLoadFailure
Assert.True() Failure
Expected: True
Actual:   False

Affected legs:

• runtime-extra-platforms (def 154) / iossimulator-arm64 Release AllSubsets_CoreCLR / exit code 1

First build it occurred:

• Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1449088
• Finished: 2026-06-04T09:47:08Z
• Occurrences in window: 5+ (builds 1449088, 1450787, 1452386, 1452872, 1453379)
• Not present in build 1442382 (2026-05-31); regression likely introduced between May 31 and June 4.

Error Message

{
  "ErrorMessage": ["System.Reflection.Tests.AssemblyTests.AssemblyLoadWithPublicKey", "Could not load file or assembly 'System.Runtime, Culture=neutral, PublicKeyToken=null'"],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

---

Filed by ci-failure-scan, which scans dnceng-public outer-loop pipelines on main and converts stable failures into KBEs and test-disable PRs. Comment here or on the workflow file to suggest changes; ci-failure-scan-feedback reads in-scope feedback daily and opens (or updates) a PR with prompt edits.

Note

🔒 Integrity filter blocked 5 items

The following items were blocked because they don't meet the GitHub integrity level.

• #56073 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #128392 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #107933 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #29383 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #110173 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".

To allow these resources, lower min-integrity in your GitHub frontmatter:

tools:
  github:
    min-integrity: approved  # merged | approved | unapproved | none

Generated by CI Outer-Loop Failure Scanner · ● 48.3M · ◷

Report

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	0	0

[github-actions]

Workflow artifact: ci-fix
Artifact kind: handoff
Linked KBE: #129149

Note

AI/Copilot-generated triage note.

This Known Build Error has no producible automated code change (reason: product bug in the assembly loader on iossimulator-arm64 CoreCLR — the fix requires changes to assembly resolution internals that exceed automated small-fix bounds), so I could not open even a best-effort PR. Looping in owners so it can be fixed forward rather than muted.

Root cause (best analysis)

AssemblyTests.AssemblyLoadWithPublicKey fails on iossimulator-arm64 (AllSubsets_CoreCLR) because Assembly.Load(new AssemblyName("System.Runtime")) throws FileNotFoundException:

System.IO.FileNotFoundException : Could not load file or assembly 'System.Runtime, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.

The test creates an AssemblyName with just the simple name "System.Runtime" (no version, no public key token, no culture), then calls Assembly.Load(). On most platforms, the assembly resolver successfully locates System.Runtime by simple name alone. On iossimulator-arm64 CoreCLR, the resolution fails — likely due to a difference in how the iOS app bundle layout or trimming affects assembly probing when the PublicKeyToken is null.

The second failing test (AssemblyGetForwardedTypesLoadFailure) likely depends on the same resolution path.

Evidence

• Failing build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1452872
• First build it occurred: build 1449088, 2026-06-04T09:47:08Z (computed within the scanned window; may not be the true origin)
• Not present in build 1442382 (2026-05-31); regression likely introduced between May 31 and June 4
• Possible related PR: none identified with sufficient confidence — no assembly loader commits found in the window

Suggested reviewers / area contacts

• Area owners (area-AssemblyLoader): @elinor-fung, @dotnet/runtime-infrastructure

A fix would likely involve adjusting the assembly probing logic on iOS to correctly resolve assemblies by simple name when no public key token is specified, similar to how other platforms handle this case.

Note

🔒 Integrity filter blocked 2 items

The following items were blocked because they don't meet the GitHub integrity level.

• #128501 search_pull_requests: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• [ci-scan] Test failure: CryptoStreamTests.ReadWrite_Success MemberData not found on maccatalyst #128451 issue_read: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".

To allow these resources, lower min-integrity in your GitHub frontmatter:

tools:
  github:
    min-integrity: approved  # merged | approved | unapproved | none

Generated by CI Outer-Loop Failure Fixer · ● 20.1M · ◷

[jeffschwMSFT]

removing blocking-clean-ci as it has not failed in 30 days

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	0	0

[matouskozak]

The test is no-longer failing, see https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-6c09e9bdc534462991/System.Reflection.Tests/1/console.bed47e4d.log?helixlogtype=result&skoid=8eda00af-b5ec-4be9-b69b-0919a2338892&sktid=72f988bf-86f1-41af-91ab-2d7cd011db47&skt=2026-07-24T12%3A04%3A30Z&ske=2026-07-24T13%3A04%3A30Z&sks=b&skv=2026-02-06&sv=2026-02-06&se=2026-07-24T13%3A04%3A30Z&sr=b&sp=rl&sig=8sZcCWQvrn8BHW1XcyIDut6PeQL9JKWZGe3FMOE1oqQ%3D