[release/8.0-preview4] Add suppression message to JSON serialization

[github-actions]

Backport of #47908 to release/8.0-preview4

/cc @eerhardt

Add suppression message to JSON serialization

Adds trimming and AOT suppressions in the Minimal API source generated code

Description

With the latest aspnetcore and Minimal API Source Generator, Native AOT users are getting a warning coming from generated code:

Trim analysis error IL2026: Microsoft.AspNetCore.Http.Generated.<GeneratedRouteBuilderExtensions_g>F69328E0708B4B584C5AACA22FE2C51A1CF192D6622828F613FC57C583CA77B63__GeneratedRouteBuilderExtensionsCore.ExecuteObjectResult(Object, HttpContext): Using member 'Microsoft.AspNetCore.Http.HttpResponseJsonExtensions.WriteAsJsonAsync<TValue>(HttpResponse, TValue, CancellationToken)' which has 'RequiresUnreferencedCodeAttribute' can break functionality when trimming application code. JSON serialization and deserialization might require types that cannot be statically analyzed. Use the overload that takes a JsonTypeInfo or JsonSerializerContext, or make sure all of the required types are preserved.

The issue that this warning is alerting us to is handled through the JsonSerializer.IsReflectionEnabledByDefault feature switch and can be suppressed.

Customer Impact

With Native AOT (and trimming), the warnings are the main communication to the app developer that their app might not work after publishing. If an app doesn't contain warnings, we guarantee the app will continue to work as it did before publishing.

By always having an errant warning coming from generated code, developers will be confused and think they are doing something wrong. This makes the AOT experience unacceptable. The warnings need to be actionable by the developer.

Regression?

• Yes
• No

8.0-preview3 didn't have any AOT warnings in the dotnet new api --aot template. Without this change, it does now.

Risk

• High
• Medium
• Low

The change is just adding a warning suppression to the Minimal API source generated code. There is already the same suppression in another place. Adding it in one more is very unlikely to cause problems.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

[ghost]

Hi @github-actions[bot]. Please make sure you've updated the PR description to use the Shiproom Template. Also, make sure this PR is not marked as a draft and is ready-to-merge.

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[ghost]

Hi @github-actions[bot]. This PR was just approved to be included in the upcoming servicing release. Somebody from the @dotnet/aspnet-build team will get it merged when the branches are open. Until then, please make sure all the CI checks pass and the PR is reviewed.

[eerhardt]

Approved in email.