Documentation status of _AggressiveAttributeTrimming

[MichalStrehovsky]

These options are currently not documented on learn, but Blazor WASM enables them by default. So customers who get broken by this have no recourse but to dig into undocumented properties. Should these be documented?

https://github.com/dotnet/sdk/blob/16546adca23bbbea314c734a684ea696b866d5fd/src/BlazorWasmSdk/Targets/Microsoft.NET.Sdk.BlazorWebAssembly.6_0.targets#L49-L50

Cc @dotnet/illink @eerhardt

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Issue Details

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These options are currently not documented on learn, but Blazor WASM enables them by default. So customers who get broken by this have no recourse but to dig into undocumented properties. Should these be documented?

https://github.com/dotnet/sdk/blob/16546adca23bbbea314c734a684ea696b866d5fd/src/BlazorWasmSdk/Targets/Microsoft.NET.Sdk.BlazorWebAssembly.6_0.targets#L49-L50

Cc @dotnet/illink @eerhardt

Author:	MichalStrehovsky
Assignees:	-
Labels:	linkable-framework, area-Tools-ILLink
Milestone:	-

[MichalStrehovsky]

If _AggressiveAttributeTrimming (or it's renamed equivalent) become public, we need to do something for #88994.

[Sergio0694]

Would a documented version of _AggressiveAttributeTrimming unconditionally trim all attributes, or would it be able to preserve some? Eg. those it can see code specifically looking for (ie. via calls to GetCustomAttribute<T>, etc.), or perhaps via opt-in in some way? Asking because it sounds nice on paper, and I'm wondering how/if we could benefit from this too in CsWinRT, which does need to preserve a few attributes needed to support the interop infrastructure though 🤔

[MichalStrehovsky]

Would a documented version of _AggressiveAttributeTrimming unconditionally trim all attributes, or would it be able to preserve some? Eg. those it can see code specifically looking for (ie. via calls to GetCustomAttribute<T>, etc.), or perhaps via opt-in in some way? Asking because it sounds nice on paper, and I'm wondering how/if we could benefit from this too in CsWinRT, which does need to preserve a few attributes needed to support the interop infrastructure though 🤔

You're basically asking for #103934. Yep, it would be great if attribute stripping was done in way that it doesn't break apps. It currently does break apps.

[sbomer]

Closing this because the feature switch was removed in #103970, and we don't want to support/document the current attribute trimming model. See more context in #103004 (comment).

[MichalStrehovsky]

_AggressiveAttributeTrimming still exists though and looks like Android enables it: https://github.com/dotnet/android/blob/1f822a6fa58e78981b3c80de696a815fb1e65026/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets#L119-L120

[sbomer]

I'm not sure what we should do here (aside from implementing #103934 as a better long-term solution).

_AggressiveAttributeTrimming is an underscored property, which I understand to mean "intentionally undocumented and technically unsupported". Do we really want to document it? Maybe we should push on Android to stop using it instead? I opened dotnet/android#9060 for discussion.

[MichalStrehovsky]

The issue is that if Android opts into it and someone gets broken by it, they don't know what hit them and how to disable it. Documenting would involve dropping the underscore. Android SDK would ideally not do that. We can still keep the underscored feature for experimentation or just delete it.

[sbomer]

Android removed it in dotnet/android#9062.

[sbomer]

Closing this since the only remaining work is for xamarin-macios to remove use of the property.