[ci-fix] Use DoNotWrapExceptions across ReflectionMemberAccessor Invoke paths

[github-actions]

Workflow artifact: ci-fix
Artifact kind: help
Linked KBE: #128766

> [!NOTE]
> This is an AI/Copilot-generated fix updated after PR feedback and validated with targeted local build/test runs.

Root cause (best analysis)

AsyncEnumerableTests.SerializeAsyncEnumerable_*_PartialItemFailure_PriorItemsAreFullyWritten fails on tvos-arm64 AllSubsets_Mono because the test expects InvalidOperationException but receives TargetInvocationException.

The failing log line:

[FAIL] ...AsyncEnumerableTests_AsyncPipeSerializer.SerializeAsyncEnumerable_TopLevelValues_PartialItemFailure_PriorItemsAreFullyWritten
Expected: typeof(System.InvalidOperationException)
Actual:   typeof(System.Reflection.TargetInvocationException)

On Mono/tvOS (AOT environments), System.Text.Json uses ReflectionMemberAccessor, where reflection Invoke can wrap target exceptions. CoreCLR commonly uses ReflectionEmitMemberAccessor, which propagates underlying exceptions directly.

Attempted fix

Updated ReflectionMemberAccessor to apply BindingFlags.DoNotWrapExceptions on NET targets across relevant reflection Invoke call sites in the file (including property accessors and other Invoke usages raised in review), while preserving non-NET compatibility paths.

Additional polish from feedback:

• Kept exception behavior aligned with ReflectionEmitMemberAccessor for add-method delegate behavior.
• Improved null-handling/diagnostics for union accessor delegate creation.

What is unverified / where I need help

• Full matrix/platform validation (especially tvOS Mono) still depends on CI legs; local validation was targeted.

Validation

• ./build.sh clr+libs -rc release ✅
• ./build.sh clr+libs+host -rc release -lc release ✅
• dotnet build src/libraries/System.Text.Json/src/System.Text.Json.csproj -c Release ✅
• dotnet build /t:test src/libraries/System.Text.Json/tests/System.Text.Json.Tests/System.Text.Json.Tests.csproj -p:Configuration=Release /p:XunitMethodName=System.Text.Json.Serialization.Tests.AsyncEnumerableTests_AsyncPipeSerializer.SerializeAsyncEnumerable_TopLevelValues_PartialItemFailure_PriorItemsAreFullyWritten ✅

Evidence

• Failing build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1438268
• First build it occurred: build 1433744, finished 2026-05-25T09:02:27Z (computed within scanned window; may not be true origin)
• Suspected regressing change: none identified with sufficient confidence

Help wanted

• Area owners (area-System.Text.Json): @StephenMolloy, @dotnet/area-system-text-json

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Filed by ci-failure-fix. 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.

> [!WARNING]
>

> Generated by CI Outer-Loop Failure Fixer · ● 35M · ◷

[Copilot]

Pull request overview

Updates System.Text.Json’s reflection-based MemberAccessor implementation to avoid TargetInvocationException wrapping when invoking constructors/methods via reflection, aligning exception propagation with the ReflectionEmit-based accessor paths.

Changes:

• Use BindingFlags.DoNotWrapExceptions for reflection Invoke calls when targeting #if NET.
• On non-NET TFMs, unwrap TargetInvocationException.InnerException via ExceptionDispatchInfo to preserve the original exception and stack.
• Apply this across parameterless/parameterized constructors, add-method delegates, and property getter/setter delegates.

Show a summary per file

File	Description
src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/ReflectionMemberAccessor.cs	Adjusts reflection invocation patterns to avoid exception wrapping and preserve original exception behavior.

Copilot's findings

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