Fix Apple NativeAOT test harness crash from string P/Invoke marshalling by kotlarmilos · Pull Request #130341 · dotnet/runtime

kotlarmilos · 2026-07-08T08:59:36Z

Description

The Apple NativeAOT test harness aborts on startup with MarshalDirectiveException before any test runs. Its mono_ios_set_summary and mono_ios_append_output __Internal P/Invokes take a string, and the harness file is compiled into library test assemblies that apply [assembly: DisableRuntimeMarshalling] through src/libraries/Common/src/DisableRuntimeMarshalling.cs. Under that attribute the NativeAOT compiler disallows non-blittable string marshalling even with [MarshalAs(UnmanagedType.LPUTF8Str)], so it emits a stub that throws at startup. This change switches the externs to a blittable IntPtr and converts the string to a null-terminated UTF-8 buffer in managed code with Marshal.StringToCoTaskMemUTF8, matching the native const char* in src/tasks/AppleAppBuilder/Templates/main-console.m. A blittable P/Invoke needs no runtime marshalling and stays correct on Mono and NativeAOT.

Fixes #130219.

AppleTestRunner.cs declares the mono_ios_set_summary and mono_ios_append_output __Internal P/Invokes with a string parameter. This file is compiled into every library test assembly. Several of those assemblies apply [assembly: DisableRuntimeMarshalling] through Common/src/DisableRuntimeMarshalling.cs, which disallows non-blittable P/Invoke marshalling. Under that attribute the NativeAOT compiler cannot marshal the string argument, even with [MarshalAs(UnmanagedType.LPUTF8Str)], so it emits a stub that throws MarshalDirectiveException. The harness aborts on startup before any test runs, failing every affected work item on the Apple NativeAOT test legs. Change the extern declarations to take a blittable IntPtr and convert the string to a null-terminated UTF-8 buffer in managed code with Marshal.StringToCoTaskMemUTF8, matching the native const char* signature in main-console.m. A blittable P/Invoke requires no runtime marshalling, so it compiles and runs under DisableRuntimeMarshalling and remains correct on Mono and NativeAOT. Fixes dotnet#130219 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

dotnet-policy-service · 2026-07-08T09:00:50Z

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Pull request overview

This PR updates the Apple NativeAOT library test harness (SimpleTestRunner) to avoid unsupported string marshalling in __Internal P/Invokes by switching the native imports to a blittable IntPtr signature and performing explicit UTF-8 allocation/free in managed code. This aligns the managed interop with the native const char* functions used by the AppleAppBuilder template and prevents the harness from aborting before any tests execute on Apple NativeAOT legs.

Changes:

Replace string-typed DllImport("__Internal") declarations with IntPtr-typed native entrypoints.
Add managed wrappers that convert string to a null-terminated UTF-8 buffer via Marshal.StringToCoTaskMemUTF8 and free it with Marshal.FreeCoTaskMem.

Show a summary per file

File	Description
src/libraries/Common/tests/AppleTestRunner/AppleTestRunner.cs	Switches `mono_ios_*` P/Invokes to blittable `IntPtr` and adds UTF-8 allocation/free wrappers to avoid runtime marshalling.

Copilot's findings

Files reviewed: 1/1 changed files
Comments generated: 0

kotlarmilos · 2026-07-08T09:45:47Z

/azp run runtime-extra-platforms

azure-pipelines · 2026-07-08T09:46:00Z

Azure Pipelines successfully started running 1 pipeline(s).

MichalStrehovsky · 2026-07-08T13:23:43Z

Under that attribute the NativeAOT compiler disallows non-blittable string marshalling even with [MarshalAs(UnmanagedType.LPUTF8Str)]

Yes, this is not supposed to work and I don't think it works with CoreCLR either. The fact it works on Mono is a bit concerning because DisableRuntimeMarshalling is supposed to fully disable it. I guess if we didn't run into issues so far, it's probably fine for one more release.

Does [LibraryImport] work here? You could replace the [DllImport] with [LibraryImport] and that will do the marshalling for you.

kotlarmilos · 2026-07-08T13:58:47Z

Under that attribute the NativeAOT compiler disallows non-blittable string marshalling even with [MarshalAs(UnmanagedType.LPUTF8Str)]

Yes, this is not supposed to work and I don't think it works with CoreCLR either. The fact it works on Mono is a bit concerning because DisableRuntimeMarshalling is supposed to fully disable it. I guess if we didn't run into issues so far, it's probably fine for one more release.

Does [LibraryImport] work here? You could replace the [DllImport] with [LibraryImport] and that will do the marshalling for you.

[LibraryImport] should work, but the generated stub is unsafe, which is why I went with it. If you prefer [LibraryImport] for consistency, I am happy to switch it.

jkotas · 2026-07-08T14:41:14Z

[LibraryImport] should work, but the generated stub is unsafe, which is why I went with it.

The APIs you are calling directly are unsafe too, and they will require unsafe annotations in not-too-distant future as well.

Replace the manual `IntPtr` plus `Marshal.StringToCoTaskMemUTF8` marshalling of `mono_ios_set_summary` and `mono_ios_append_output` with source-generated `[LibraryImport]` using `StringMarshalling.Utf8`. The generator emits a blittable `byte*` inner P/Invoke and performs the UTF-8 conversion in managed code, so no runtime string marshalling crosses the P/Invoke boundary. This keeps the harness correct under `[assembly: DisableRuntimeMarshalling]` on NativeAOT and on Mono. The generated stubs require unsafe code, so `AllowUnsafeBlocks` is enabled for the harness project and the NativeAOT iOS-like test build. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

kotlarmilos · 2026-07-08T16:32:11Z

/azp run runtime-extra-platforms

azure-pipelines · 2026-07-08T16:32:24Z

Azure Pipelines successfully started running 1 pipeline(s).

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

kotlarmilos · 2026-07-09T08:21:35Z

/ba-g unrelated extra-platforms failures, no marshalling Native AOT errors on Apple mobile

Copilot AI review requested due to automatic review settings July 8, 2026 08:59

github-actions Bot added the area-NativeAOT-coreclr label Jul 8, 2026

dotnet-policy-service Bot assigned kotlarmilos Jul 8, 2026

Copilot started reviewing on behalf of kotlarmilos July 8, 2026 09:00 View session

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kotlarmilos requested review from MichalStrehovsky and vitek-karas July 8, 2026 09:39

kotlarmilos added this to the 11.0.0 milestone Jul 8, 2026

This was referenced Jul 8, 2026

Mono iOS test failures with "The "AppleAppBuilderTask" task failed unexpectedly." in ProxyProjectForAOTOnHelix #127423

Open

Helix: System.IO.IOException: No space left on device #128758

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Copilot AI review requested due to automatic review settings July 8, 2026 16:24

Copilot started reviewing on behalf of kotlarmilos July 8, 2026 16:24 View session

Drop redundant comment in tests.ioslike.targets

8f653be

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI reviewed Jul 8, 2026

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Comment thread src/libraries/Common/tests/AppleTestRunner/AppleTestRunner.cs

Copilot AI review requested due to automatic review settings July 8, 2026 16:29

Copilot started reviewing on behalf of kotlarmilos July 8, 2026 16:29 View session

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Comment thread src/libraries/Common/tests/AppleTestRunner/AppleTestRunner.cs

MichalStrehovsky approved these changes Jul 8, 2026

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This was referenced Jul 9, 2026

[wasm] OpenQA.Selenium.WebDriverTimeoutException: timeout: Timed out receiving message from renderer #117486

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Flaky timeout in CreateFileChangeToken_RootDeletedAndRecreated_TokenFiresWhenFileCreated #129691

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kotlarmilos merged commit 7600052 into dotnet:main Jul 9, 2026
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dotnet-maestro Bot mentioned this pull request Jul 10, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#7617

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Copilot AI mentioned this pull request Jul 10, 2026

Increase vectorized Tan test tolerance #130469

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dotnet-milestone-bot Bot modified the milestones: 11.0.0, 11.0-preview7 Jul 10, 2026

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