[STJ] Account for F# CompilationMappingAttribute now supporting multiple declarations.

[eiriktsarpalis]

Addresses #114824 for .NET 10.

[Copilot]

Pull Request Overview

This PR updates how the code retrieves the FSharp compilation mapping attributes to support multiple attribute declarations for .NET 10.

• In GetFSharpCompilationMappingAttribute, the code now retrieves all attributes and returns the first explicit declaration.
• In GetFSharpCoreAssembly, the attribute lookup is modified to ignore inherited attributes.

Files not reviewed (1)

• src/libraries/System.Text.Json/tests/System.Text.Json.FSharp.Tests/RecordTests.fs: Language not supported

Comments suppressed due to low confidence (2)

src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/FSharpCoreReflectionProxy.cs:208

• Switching from GetCustomAttribute with inherit:true to retrieving all attributes with inherit:false and using the first one might overlook multiple explicit declarations. Please verify that only the first attribute is sufficient for the intended behavior.

object[] attributes = type.GetCustomAttributes(_compilationMappingAttributeType, inherit: false);

src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/FSharpCoreReflectionProxy.cs:218

• Changing the attribute lookup from inherit:true to inherit:false might omit inherited attributes that could be relevant. Confirm that this adjustment aligns with the intended F# core assembly resolution behavior.

foreach (Attribute attr in type.GetCustomAttributes(inherit: false))

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
See info in area-owners.md if you want to be subscribed.

[jeffhandley]

When you say, "Partially addresses," do you mean that it only addresses the issue for .NET 10, or do you mean that there are scenarios in .NET 10 still not addressed with this as well?

[eiriktsarpalis]

When you say, "Partially addresses," do you mean that it only addresses the issue for .NET 10, or do you mean that there are scenarios in .NET 10 still not addressed with this as well?

I sorry, I should have said this addresses it fully for 10, but it shouldn't be used to close the underlying issue as we're working out resolution strategies for .NET 8 and 9.

[jeffhandley]

/ba-g The failures are all known and unrelated and they are not transient.

[eiriktsarpalis]

/backport to release/9.0-staging

[github-actions]

Started backporting to release/9.0-staging: https://github.com/dotnet/runtime/actions/runs/14681001692

[eiriktsarpalis]

/backport to release/8.0-staging

[github-actions]

Started backporting to release/8.0-staging: https://github.com/dotnet/runtime/actions/runs/14681004374