[API Proposal]: Add `LocalPath` property to `RuntimeFile` and `ResourceAssembly` in `Microsoft.Extensions.DependencyModel`

[elinor-fung]

Background and motivation

The SDK uses Microsoft.Extensions.DependencyModel to create the .deps.json for an application or library. This file includes dependencies such as NuGet package assets. Currently, the path written to the file for those assets is that relative path in the NuGet package. It does not indicate the actual path on disk relative to the application.

This means that at run time, the host makes assumptions about where the file will be relative to the application. As a result, any custom relative path (for example, trying to put a dependency in a subfolder next to the app) is not respected. In order to support this, the expected path on disk also needs to be included in the .deps file.

The additional information is needed to address.

• Relative path in deps.json is ignored for assemblies from the app #3525
• Generated .deps.json for a resolved package should include path relative to published app layout sdk#48406

These issues are also related to a broader desire around allowing customization of app layout - anything we do there will probably require a fix for these issues.

cc @dotnet/appmodel @dsplaisted @richlander

API Proposal

namespace Microsoft.Extensions.DependencyModel;

public partial class ResourceAssembly
{
    public ResourceAssembly(string path, string locale);
+   public ResourceAssembly(string path, string locale, string? localPath);
    public string Locale { get; set; }
    public string Path { get; set; }
+   public string? LocalPath { get; }
}

public partial class RuntimeFile
{
    public RuntimeFile(string path, string? assemblyVersion, string? fileVersion);
+   public RuntimeFile(string path, string? assemblyVersion, string? fileVersion, string? localPath);
    public string? AssemblyVersion { get; }
    public string? FileVersion { get; }
    public string Path { get; }
+   public string? LocalPath { get; }
}

API Usage

var runtimeFile = new RuntimeFile("lib/net10.0/lib.dll", "1.0.0", "1.0.0", "lib.dll");
var resourceAssembly = new ResourceAssembly("lib/net10.0/fr/lib.resources.dll", "fr", "fr/lib.resources.dll");

string? runtimeFileLocalPath = runtimeFile.LocalPath;
string? resourceAssemblyLocalPath = resourceAssembly.LocalPath;

Example from current .deps.json file:

"MyPackage/1.0.0": {
  "runtime": {
    "lib/net10.0/lib.dll": {
      "assemblyVersion": "1.0.0",
      "fileVersion": "1.0.0"
    },
    "resources": {
      "lib/net10.0/fr/lib.resources.dll": {
        "locale": "fr"
      }
    }
  }
}

Example of .deps with additional information that this proposal would enable:

"MyPackage/1.0.0": {
  "runtime": {
    "lib/net10.0/lib.dll": {
      "assemblyVersion": "1.0.0",
      "fileVersion": "1.0.0",
      "localPath": "lib.dll"
    },
    "resources": {
      "lib/net10.0/fr/lib.resources.dll": {
        "locale": "fr",
        "localPath": "fr/lib.resources.dll"
      }
    }
  }
}

Alternative Designs

No response

Risks

No response

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[dsplaisted]

LGTM 👍

[bes207863]

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[jeffhandley]

@elinor-fung Are you planning to drive this through API Review and implementation? If you're planning to consume this in .NET 10, this would be reasonable to add in RC1; otherwise we would punt it to .NET 11.

[elinor-fung]

Yes, I am planning to drive this through API review and implementation. I'm hoping to consume it in .NET 10.

[bartonjs]

Video

Looks good as proposed

namespace Microsoft.Extensions.DependencyModel;

public partial class ResourceAssembly
{
    public ResourceAssembly(string path, string locale, string? localPath);
    public string? LocalPath { get; }
}

public partial class RuntimeFile
{
    public RuntimeFile(string path, string? assemblyVersion, string? fileVersion, string? localPath);
    public string? LocalPath { get; }
}