CI flake: Smoketests (Linux 1/1) / standalone::csharp_aot_module::test_build_csharp_module_aot

[clockwork-labs-bot]

Detected by CI Gremlin after a failed GitHub Actions attempt succeeded on rerun.

Tests:

• standalone::csharp_aot_module::test_build_csharp_module_aot

Error:
thread 'standalone::csharp_aot_module::test_build_csharp_module_aot' (11146) panicked at crates/smoketests/tests/standalone/csharp_aot_module.rs:77:5:
NativeAOT-LLVM publish failed:

Failed job runs:

• https://github.com/clockworklabs/SpacetimeDB/actions/runs/35073899631/job/104723069533 (Smoketests (Linux 1/1), attempt 1 -> 2)

Timeout detection:

• none

Context:

• none

[clockwork-labs-bot]

Diagnosis for the linked job: run 35073899631, job 104723069533 (Smoketests (Linux 1/1)), attempt 1.

The failing step was Run smoketest partition (Linux). Setup completed, the C# packages built, and nextest ran 48 standalone smoketests. The only failed test was standalone::csharp_aot_module::test_build_csharp_module_aot.

Failure signature:

NativeAOT-LLVM publish failed
Microsoft.NETCore.Native.targets(377,5): error MSB3073: .../runtime.linux-x64.microsoft.dotnet.ilcompiler.llvm/10.0.0-rc.1.26357.1/tools//ilc @obj/Release/net10.0/wasi-wasm/native/StdbModule.ilc.rsp exited with code 139

Root cause for this exact attempt: the experimental NativeAOT-LLVM ilc compiler crashed with exit code 139 while publishing modules/sdk-test-cs for net10.0/wasi-wasm. This is a toolchain/compiler crash in the C# AOT publish path, not a SpacetimeDB runtime assertion, runner setup failure, or timeout. The preceding IL3050 line is an AOT analysis warning and does not appear to be the direct failure; the hard failure is the ilc process crash.

Suggested title: CI flake: NativeAOT-LLVM ilc exits 139 building C# AOT smoketest

Duplicate search:

• Searched public issues for NativeAOT-LLVM publish failed, ilc exited with code 139, Microsoft.DotNet.ILCompiler.LLVM, csharp_aot_module, MSB3073 ilc, runtime.linux-x64.microsoft.dotnet.ilcompiler.llvm, and broad code 139 terms.
• Similar public tickets exist, but I did not find a close Test Flakes duplicate for this exact mechanism.
• CI flake: Nuget Unable to load the service index for source #5303 and CI flake: Smoketests (Windows) / smoketests::csharp_aot_module::test_build_csharp_module_aot #5312 share the NativeAOT-LLVM publish failed wrapper, but they were Windows NuGet/service-index failures, not a Linux ilc exit-139 crash.
• NativeAOT-LLVM for .NET 8 has issues with the JsonSerializerContext Case Insensitivity #5568 is related NativeAOT-LLVM work, but it tracks a deterministic JsonSerializerContext/AOT issue with ilc exit 1, not this Linux compiler crash.
• C# module build pipeline depends on deprecated .NET workload; AOT compilation path needed #4514 is the broader public C# AOT path tracker, not a Test Flakes duplicate.

Top duplicate candidate: none close enough to mark as a duplicate. Leaving this open.