[API Proposal]: Expose `Assembly.GetSimpleName()`

[Youssef1313]

Background and motivation

Today, getting assembly simple name is done via assembly.GetName().Name. This does more work than necessary, like GetCodeBase, GetPublicKey, GetVersion, and allocating AssemblyName instance. In a hot code path, this can be problematic.

API Proposal

namespace System.Reflection;

public abstract partial class Assembly
{
+   public virtual string GetSimpleName() => GetName().Name;
}

internal sealed partial class RuntimeAssembly : Assembly
{
-       internal string GetSimpleName()
+       public override string GetSimpleName()
        {
            RuntimeAssembly runtimeAssembly = this;
            string? name = null;
            GetSimpleName(new QCallAssembly(ref runtimeAssembly), new StringHandleOnStack(ref name));
            return name!;
        }
}

internal class DelegatingAssembly : Assembly
{
+       public override string GetSimpleName() => UnderlyingAssembly.GetSimpleName();
}

internal sealed partial class RuntimeAssemblyBuilder : AssemblyBuilder
{
+       public override string GetSimpleName() => InternalAssembly.GetSimpleName();
}

public sealed class PersistedAssemblyBuilder : AssemblyBuilder
{
+       public override string GetSimpleName() => _assemblyName.Name;
}

API Usage

Example:

_ = typeof(MyType).Assembly.GetSimpleName();

// Instead of:
_ = typeof(MyType).Assembly.GetName().Name;

Alternative Designs

Do nothing, and callers who have perf issues can introduce caching themselves.

The perf issue is more likely to be "querying the same assembly/assemblies over and over again" and not "querying too many different assemblies".

This was motivated by the perf investigations found in microsoft/vstest#15259 though.

Risks

No response

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[AaronRobinsonMSFT]

@Youssef1313 Can you elaborate on what the simple name is being used for? Is this a logging mechanism or is the simple name being used for some other purpose?

[Youssef1313]

@AaronRobinsonMSFT For our case, it's mostly used for display purposes in VS Test Explorer.

[teo-tsirpanis]

You can read only the assembly's name with the help of System.Reflection.Metadata and AssemblyExtensions.TryGetRawMetadata. It might result in some extra metadata parsing, but it will be the most efficient thing memory-wise.

If we want to add a new method on Assembly, we can add one that returns AssemblyNameInfo, which is immutable and can be cached by the objects.

[jkotas]

You can read only the assembly's name with the help of System.Reflection.Metadata and AssemblyExtensions.TryGetRawMetadata. It might result in some extra metadata parsing, but it will be the most efficient thing memory-wise.

I expect that this would be significantly less efficient compared to assembly.GetName().Name.

If we want to add a new method on Assembly, we can add one that returns AssemblyNameInfo,

This would not fully address the inefficiency. AssemblyNameInfo costs about as much to allocate as AssemblyName. Also, AssemblyNameInfo lives in System.Reflection.Metadata. Moving AssemblyNameInfo to System.Runtime/Corelib is possible for newer runtimes, but somewhat complicated.

[ThomasGoulet73]

It could be used in WPF to replace this helper:
https://github.com/dotnet/wpf/blob/b4e470e583593fd593818ced9b2f6409a2b56c50/src/Microsoft.DotNet.Wpf/src/Shared/MS/Internal/ReflectionUtils.cs#L48-L80

The helper is used in a bunch of places in WPF:
https://github.com/search?q=repo%3Adotnet%2Fwpf%20GetAssemblyPartialName&type=code