SOS VarargPInvoke test expects a stub signature without the explicit secret argument #6165

Description

SOS.Tests.VarargPInvokeTests.VarargPInvoke_ReportsInteropMethodAndDisassemblesStub fails because its exact expected IL stub signature omits the explicit secret-context parameter.

The test expects:

ILStubClass.IL_STUB_PInvoke(System.String, Int32, Double, ...)

Both legacy DAC and cDAC report:

ILStubClass.IL_STUB_PInvoke(System.String, Int32, Double, IntPtr, ...)

The failure occurs at frames.SingleRow(...), before the subsequent ip2md, clru, and clru -il assertions run.

Configuration

Observed in dotnet/runtime#135805, diagnostics build 1651653:

• Windows x64 and arm64, Release, .NET 12 private runtime.
• Both SOS and SOS_EnumMemory jobs.
• Windows/CDB live debugging; x64 console confirms the same mismatch with both legacy DAC and cDAC.

Regression?

The exact-string assertion was introduced by #6155 on October 26, 2026.

The additional IntPtr is expected runtime behavior: dotnet/runtime#132534 made IL stub secret context an explicit native int modreq(SecretStubArgument) parameter. In src/coreclr/vm/dllimport.cpp, StubNeedsSecretArgument selects vararg forward stubs and AppendSecretStubArgument appends ELEMENT_TYPE_I. These helpers are unchanged by dotnet/runtime#135805.

Other information

Suggested fix: update the expected StubName in VarargPInvokeTests.cs for the applicable runtime versions, preserving the existing stack, method-resolution, and disassembly assertions. Rerun the test to validate the later assertions, which the current failure prevents from executing.

x64 Helix console

SOS.TestHarness.SosAssertException : SOS assertion failed.
  host:     cdb
  command:  clrstack
  expected: exactly one row where Function is ILStubClass.IL_STUB_PInvoke(System.String, Int32, Double, ...) (found 0)

This report is based on CI results and source inspection; no local Windows reproduction or proposed fix has been run.