Fix bug mixing .NET SDKs

src/Shared/DotnetUtil.cs

@@ -1,5 +1,7 @@
-using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.Build.Logging.StructuredLogger;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Configuration.Internal;
 using System.Diagnostics;
@@ -12,11 +14,34 @@ namespace Basic.CompilerLog;
 
 internal static class DotnetUtil
 {
+    private static readonly Lazy<Dictionary<string, string>> _lazyDotnetEnvironmentVariables = new(CreateDotnetEnvironmentVariables);
+
+    private static Dictionary<string, string> CreateDotnetEnvironmentVariables()
+    {
+        // The CLI, particularly when run from dotnet test, will set the MSBuildSDKsPath environment variable
+        // to point to the current SDK. That could be an SDK that is higher than the version that our tests
+        // are executing under. For example `dotnet test` could spawn an 8.0 process but we end up testing
+        // the 7.0.400 SDK. This environment variable though will point to 8.0 and end up causing load 
+        // issues. Clear it out here so that the `dotnet` commands have a fresh context.
+        var map = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        foreach (DictionaryEntry entry in Environment.GetEnvironmentVariables())
+        {
+            var key = (string)entry.Key;
+            if (!string.Equals(key, "MSBuildSDKsPath", StringComparison.OrdinalIgnoreCase))
+            {
+                map.Add(key, (string)entry.Value!);
+
+            }
+        }
+        return map;
+    }
+
     internal static ProcessResult Command(string args, string? workingDirectory = null) =>
         ProcessUtil.Run(
             "dotnet",
             args,
-            workingDirectory: workingDirectory);
+            workingDirectory: workingDirectory,
+            environment: _lazyDotnetEnvironmentVariables.Value);
 
     internal static void CommandOrThrow(string args, string? workingDirectory = null)
     {

src/Shared/ProcessUtil.cs

@@ -1,9 +1,11 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Drawing.Printing;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using MessagePack.Formatters;
 
 namespace Basic.CompilerLog;
 
@@ -28,7 +30,8 @@ internal static class ProcessUtil
     internal static ProcessResult Run(
         string fileName,
         string args,
-        string? workingDirectory = null)
+        string? workingDirectory = null,
+        Dictionary<string, string>? environment = null)
     {
         var info = new ProcessStartInfo()
         {
@@ -40,11 +43,20 @@ internal static ProcessResult Run(
             RedirectStandardError = true,
         };
 
+        if (environment is not null)
+        {
+            info.Environment.Clear();
+            foreach (var tuple in environment)
+            {
+                info.Environment.Add(tuple.Key, tuple.Value);
+            }
+        }
+
         var process = Process.Start(info)!;
         var standardOut = process.StandardOutput.ReadToEnd();
         var standardError = process.StandardError.ReadToEnd();
-
         process.WaitForExit();
+
         return new ProcessResult(
             process.ExitCode,
             standardOut,