Dayforce.LocalSdkResolver.cs

using System;
using System.IO;
using Microsoft.Build.Framework;

namespace Dayforce.LocalSdkResolver;

/// <summary>
/// A generic MSBuild SDK resolver for local SDK development.
///
/// Set the LOCAL_SDK_ROOTS environment variable to a semicolon-delimited
/// list of directories that contain SDK folders. For each SDK reference,
/// the resolver checks {root}/{SdkName}/Sdk/Sdk.props in order.
///
/// Example:
///   SET LOCAL_SDK_ROOTS=C:\myrepo\sdk;D:\shared\sdks
///
/// With that, <Project Sdk="My.Custom.Sdk"> resolves if
/// C:\myrepo\sdk\My.Custom.Sdk\Sdk\Sdk.props exists.
/// </summary>
public class LocalSdkResolver : SdkResolver
{
    private const string EnvVarName = "LOCAL_SDK_ROOTS";

    public override string Name => "Dayforce.LocalSdkResolver";

    // After NuGet (~5000), before Default (10000).
    // Published/versioned SDKs take precedence; this is a dev-time fallback.
    public override int Priority => 9000;

    public override SdkResult Resolve(
        SdkReference sdkReference,
        SdkResolverContext resolverContext,
        SdkResultFactory factory)
    {
        string roots = Environment.GetEnvironmentVariable(EnvVarName);

        if (string.IsNullOrEmpty(roots))
        {
            // Env var not set — silently decline so other resolvers can handle it.
            return factory.IndicateFailure(null);
        }

        foreach (string root in roots.Split([';'], StringSplitOptions.RemoveEmptyEntries))
        {
            string trimmed = root.Trim();
            if (trimmed.Length == 0) continue;

            string candidate = Path.Combine(trimmed, sdkReference.Name, "Sdk");
            string propsFile = Path.Combine(candidate, "Sdk.props");

            if (File.Exists(propsFile))
            {
                resolverContext.Logger.LogMessage(
                    $"{Name}: Resolved '{sdkReference.Name}' from '{candidate}'",
                    MessageImportance.Low);
                return factory.IndicateSuccess(candidate, string.Empty);
            }
        }

        return factory.IndicateFailure([
            $"{Name}: '{sdkReference.Name}' not found in any LOCAL_SDK_ROOTS path."
        ]);
    }
}