Fix Compiler.config not being initialized by default

* Extended whitelist tests to use the other method of creating a compiler without explicit compiler settings
* Initialize Compiler._config as it's a struct so everything was zeroed before

engine/Sandbox.Compiling.Test/Data/code/blacklist/UsingStatic.cs

@@ -1,3 +1,4 @@
+using System;
 using static System.Runtime.InteropServices.MemoryMarshal;
 
 class UsingStaticTest

engine/Sandbox.Compiling.Test/Tests/BlacklistTest.cs

@@ -9,6 +9,65 @@ namespace TestCompiler;
 [TestClass]
 public partial class BlacklistTest
 {
+
+	[TestMethod]
+	public async Task DefaultCompilerFailsWhitelist()
+	{
+		var codePath = System.IO.Path.GetFullPath( "data/code/blacklist" );
+		var group = new CompileGroup( "TestWhitelist" );
+
+		var compiler = group.GetOrCreateCompiler( "test" );
+		compiler.AddSourcePath( codePath );
+		compiler.MarkForRecompile();
+		await group.BuildAsync();
+
+		// Verify compilation failed due to whitelist violations
+		var output = compiler.Output;
+		Assert.IsNotNull( output );
+		Assert.IsFalse( output.Successful, "Compiler should fail with default whitelist settings" );
+		Assert.IsTrue( output.Diagnostics.Count > 0, "Should have diagnostics for whitelist violations" );
+	}
+
+	[TestMethod]
+	public async Task CompilerWithWhitelistFails()
+	{
+		var codePath = System.IO.Path.GetFullPath( "data/code/blacklist" );
+		var group = new CompileGroup( "TestWhitelist" );
+
+		var compilerSettings = new Compiler.Configuration();
+		compilerSettings.Whitelist = true;
+		compilerSettings.Unsafe = false;
+
+		var compiler = group.CreateCompiler( "test", codePath, compilerSettings );
+		await group.BuildAsync();
+
+		// Verify compilation failed due to whitelist being enabled
+		var output = compiler.Output;
+		Assert.IsNotNull( output );
+		Assert.IsFalse( output.Successful, "Compiler should fail when whitelist is explicitly enabled" );
+		Assert.IsTrue( output.Diagnostics.Count > 0, "Should have diagnostics for whitelist violations" );
+	}
+
+	[TestMethod]
+	public async Task CompilerWithoutWhitelistSucceeds()
+	{
+		var codePath = System.IO.Path.GetFullPath( "data/code/blacklist" );
+		var group = new CompileGroup( "TestWhitelist" );
+
+		var compilerSettings = new Compiler.Configuration();
+		compilerSettings.Whitelist = false;
+		compilerSettings.Unsafe = true;
+
+		var compiler = group.CreateCompiler( "test", codePath, compilerSettings );
+		await group.BuildAsync();
+
+		// Verify compilation succeeded with whitelist disabled
+		var output = compiler.Output;
+		Assert.IsNotNull( output );
+		Assert.IsTrue( output.Successful, "Compiler should succeed when whitelist is disabled" );
+		Assert.IsNull( output.Exception, "Should not have any exceptions" );
+	}
+
 	[TestMethod]
 	public async Task EndToEndBuildFailure()
 	{

engine/Sandbox.Compiling/Compiler/Compiler.Build.cs

@@ -114,10 +114,10 @@ partial class Compiler
 
 		var archive = new CodeArchive();
 		archive.CompilerName = Name;
-		archive.Configuration = config;
+		archive.Configuration = _config;
 		output.Archive = archive;
 
-		var parseOptions = config.GetParseOptions();
+		var parseOptions = _config.GetParseOptions();
 
 		//
 		// References
@@ -217,7 +217,7 @@ partial class Compiler
 		// check for blacklisted methods/types used in compilation
 		// we need this because the c# compiler will post optimize and use tons of blacklisted methods
 		// run this after generators because they can contain user inputs too
-		if ( config.Whitelist )
+		if ( _config.Whitelist )
 		{
 			RunBlacklistWalker( compiler, output );
 
@@ -242,7 +242,7 @@ partial class Compiler
 
 				peStream.Seek( 0, System.IO.SeekOrigin.Begin );
 
-				if ( config.Whitelist && Group.AccessControl is { } access )
+				if ( _config.Whitelist && Group.AccessControl is { } access )
 				{
 					var result = access.VerifyAssembly( peStream, out TrustedBinaryStream stream );
 					if ( !result.Success )

engine/Sandbox.Compiling/Compiler/Compiler.SyntaxTree.cs

@@ -78,7 +78,7 @@ partial class Compiler
 	/// </summary>
 	private string GetReplacementDirective( string filePath )
 	{
-		foreach ( var pair in config.ReplacementDirectives )
+		foreach ( var pair in _config.ReplacementDirectives )
 		{
 			if ( filePath.EndsWith( pair.Key, StringComparison.OrdinalIgnoreCase ) )
 				return pair.Value;
@@ -108,7 +108,7 @@ partial class Compiler
 				var pathFolders = folderName.Split( new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries );
 
 				// is this ignored
-				if ( pathFolders.Any( x => config.IgnoreFolders.Contains( x, StringComparer.OrdinalIgnoreCase ) ) )
+				if ( pathFolders.Any( x => _config.IgnoreFolders.Contains( x, StringComparer.OrdinalIgnoreCase ) ) )
 					return;
 
 				if ( pathFolders.Contains( "obj", StringComparer.OrdinalIgnoreCase ) )
@@ -156,7 +156,7 @@ partial class Compiler
 				{
 					tree = CSharpSyntaxTree.ParseText( text: sourceText, options: fileOptions, path: physicalPath );
 
-					if ( config.StripDisabledTextTrivia )
+					if ( _config.StripDisabledTextTrivia )
 						tree = StripDisabledTextTrivia( tree );
 				}
 
@@ -168,7 +168,7 @@ partial class Compiler
 					var wrappedSourceText = SourceText.From( wrappedText, Encoding.UTF8 );
 					tree = CSharpSyntaxTree.ParseText( wrappedSourceText, fileOptions, physicalPath );
 
-					if ( config.StripDisabledTextTrivia )
+					if ( _config.StripDisabledTextTrivia )
 						tree = StripDisabledTextTrivia( tree );
 				}
 

engine/Sandbox.Compiling/Compiler/Compiler.cs

@@ -85,7 +85,7 @@ public sealed partial class Compiler : IDisposable
 	/// <summary>
 	/// The compiler's settings. 
 	/// </summary>
-	private Compiler.Configuration config;
+	private Compiler.Configuration _config = new();
 
 	/// <summary>
 	/// Should only ever get called from CompileGroup.
@@ -134,13 +134,13 @@ public sealed partial class Compiler : IDisposable
 
 	public void SetConfiguration( Compiler.Configuration newConfig )
 	{
-		config = newConfig;
+		_config = newConfig;
 		incrementalState.Reset();
 	}
 
 	public Configuration GetConfiguration()
 	{
-		return config;
+		return _config;
 	}
 
 	/// <summary>