Drop script slot analysis opt-out

Author: rogeralsing

src/Asynkron.JsEngine/Ast/Legacy/StatementNodeExtensions.cs

@@ -2180,13 +2180,12 @@ private static JsValue EvaluateProgramJsValueCore(ProgramNode program, JsEnviron
             program.IsStrict ? ScopeMode.Strict : ScopeMode.Sloppy,
             cancellationToken,
             executionKind);
-        // For eval, always disable identifier caching/slot analysis because eval runs in the caller's
+        // For eval, always disable identifier caching because eval runs in the caller's
         // lexical environment which may contain 'with' statements or allow deletable bindings.
         // The static analysis of the eval code alone doesn't tell us about the outer context.
-        var allowScriptSlotAnalysis = context.RealmState.Options.AllowScriptSlotAnalysis &&
-                                      executionKind != ExecutionKind.Eval;
+        var allowIdentifierCache = executionKind != ExecutionKind.Eval;
         var allowsIdentifierCaching = AllowsIdentifierCaching(program);
-        context.AllowIdentifierCache = allowScriptSlotAnalysis &&
+        context.AllowIdentifierCache = allowIdentifierCache &&
                                        allowsIdentifierCaching;
         context.DrainAwaitMicrotasks = drainAwaitMicrotasks;
         if (inheritedPrivateNameScopes is { IsDefault: false, Length: > 0 } scopes)
@@ -2352,7 +2351,7 @@ trueGlobalEnvironment is not null &&
         var canUseIrPlan = context.AllowIdentifierCache || canUseNoSlotIr;
         ScriptPlanCache? scriptPlanCache = null;
         ExecutionPlan? scriptPlan = null;
-        var enableScriptSlots = allowScriptSlotAnalysis && context.AllowIdentifierCache;
+        var enableScriptSlots = context.AllowIdentifierCache;
         if (canUseIrPlan)
         {
             scriptPlanCache = ((IAstCacheable<ScriptPlanCache>)program).GetOrCreateCache();
@@ -2441,7 +2440,7 @@ trueGlobalEnvironment is not null &&
 
         if (!canUseIrPlan)
         {
-            const string failureReason = "script slot analysis disabled for non-dynamic script execution";
+            const string failureReason = "identifier caching is unavailable for non-dynamic script execution";
             context.RealmState.Logger?.LogInformation(
                 "Rejecting non-dynamic script because IR script plan is unavailable: {FailureReason}",
                 failureReason);

src/Asynkron.JsEngine/IJsEngineOptions.cs

@@ -31,12 +31,6 @@ public interface IJsEngineOptions
     /// </summary>
     bool DebugMode { get; }
 
-    /// <summary>
-    ///     Enables script-level slot analysis and identifier caching when it is safe to do so
-    ///     (no direct eval/with). Defaults to false for safety.
-    /// </summary>
-    bool AllowScriptSlotAnalysis { get; }
-
     /// <summary>
     ///     Optional logger used for realm-level diagnostics such as identifier slot hit/miss tracing.
     /// </summary>

src/Asynkron.JsEngine/JsEngineOptions.cs

@@ -19,7 +19,6 @@ public sealed class JsEngineOptions : IJsEngineOptions
     public TimeZoneInfo TimeZone { get; init; } = TimeZoneInfo.Utc;
     public bool AllowImportMeta { get; init; } = true;
     public bool DebugMode { get; init; }
-    public bool AllowScriptSlotAnalysis { get; init; } = true;
 
     /// <summary>
     /// Optional logger to receive realm traces and diagnostics.

tests/Asynkron.JsEngine.Tests.Test262/Test262Test.cs

@@ -200,13 +200,11 @@ internal static JsEngine CreateTest262Engine(ILogger? logger, bool debugMode, bo
             ? BaseRealmSnapshot.Instance.Value.CreateEngine(new JsEngineOptions
             {
                 Logger = logger,
-                AllowScriptSlotAnalysis = true,
                 DebugMode = debugMode,
             })
             : new JsEngine(new JsEngineOptions
             {
                 Logger = logger,
-                AllowScriptSlotAnalysis = true,
                 DebugMode = debugMode,
             });
 

tests/Asynkron.JsEngine.Tests/DynamicFunctionClassTestBomb.cs

@@ -46,15 +46,14 @@ public async Task H1_TopLevelScript_DefaultEngine()
         AssertBrandCheckResult(result);
     }
 
-    /// H2: The exact top-level script should also work when script slot analysis is enabled.
+    /// H2: The exact top-level script should also work when debug diagnostics are enabled.
     [Fact(Timeout = 10000)]
-    public async Task H2_TopLevelScript_WithScriptSlotAnalysis()
+    public async Task H2_TopLevelScript_WithDebugDiagnostics()
     {
         await using var engine = CreateEngine(() => new JsEngineOptions
         {
             Logger = CurrentLogger,
             DebugMode = true,
-            AllowScriptSlotAnalysis = true,
         });
 
         var result = await engine.Evaluate(PrivateMethodClassSource);

tests/Asynkron.JsEngine.Tests/ScriptSlotAnalysisTests.cs

@@ -11,27 +11,19 @@ public ScriptSlotAnalysisTests(ITestOutputHelper output) : base(output)
     }
 
     [Fact]
-    public async Task ScriptSlotAnalysisToggle_ProducesSameResult()
+    public async Task ScriptSlotAnalysis_SimpleScriptUsesIrByDefault()
     {
         const string script = """
             let a = 1;
             let b = 2;
             a + b;
             """;
 
-        await using var engineNoSlots = CreateEngine(() => new JsEngineOptions
-        {
-            AllowScriptSlotAnalysis = false
-        });
-        await using var engineWithSlots = CreateEngine(() => new JsEngineOptions
-        {
-            AllowScriptSlotAnalysis = true
-        });
+        await using var engine = CreateEngine();
 
-        await Assert.ThrowsAsync<NotSupportedException>(async () => await engineNoSlots.Evaluate(script));
-        var resultWith = await engineWithSlots.Evaluate(script);
+        var result = await engine.Evaluate(script);
 
-        Assert.Equal(3d, resultWith);
+        Assert.Equal(3d, result);
     }
 
     [Fact]
@@ -46,7 +38,6 @@ public async Task ScriptSlotAnalysis_DirectEvalWithoutCapturedWith_UsesIrPath()
 
         await using var engine = CreateEngine(() => new JsEngineOptions
         {
-            AllowScriptSlotAnalysis = true,
             DebugMode = true,
             Logger = logger
         });
@@ -61,7 +52,7 @@ static record => record.Message.Contains(
     }
 
     [Fact]
-    public async Task ScriptSlotAnalysis_DisabledWhenWithIsPresent()
+    public async Task ScriptSlotAnalysis_WithStatementUsesNoSlotIrPath()
     {
         const string script = """
             var obj = { value: 7 };
@@ -72,10 +63,7 @@ public async Task ScriptSlotAnalysis_DisabledWhenWithIsPresent()
             result;
             """;
 
-        await using var engine = CreateEngine(() => new JsEngineOptions
-        {
-            AllowScriptSlotAnalysis = true
-        });
+        await using var engine = CreateEngine();
 
         var result = await engine.Evaluate(script);
         Assert.Equal(7d, result);
@@ -96,7 +84,6 @@ public async Task ScriptSlotAnalysis_TopLevelWithWithoutCapturedWith_UsesIrPath(
 
         await using var engine = CreateEngine(() => new JsEngineOptions
         {
-            AllowScriptSlotAnalysis = true,
             DebugMode = true,
             Logger = logger
         });
@@ -122,7 +109,6 @@ public async Task ScriptSlotAnalysis_EvalWithWithoutCapturedWith_UsesIrPath()
 
         await using var engine = CreateEngine(() => new JsEngineOptions
         {
-            AllowScriptSlotAnalysis = true,
             DebugMode = true,
             Logger = logger
         });
@@ -150,7 +136,6 @@ public async Task ScriptSlotAnalysis_DirectEvalInsideWithWithoutCapturedClosure_
 
         await using var engine = CreateEngine(() => new JsEngineOptions
         {
-            AllowScriptSlotAnalysis = true,
             DebugMode = true,
             Logger = logger
         });
@@ -178,7 +163,6 @@ public async Task ScriptSlotAnalysis_DirectEvalVarDeclarationInsideWithWithoutCa
 
         await using var engine = CreateEngine(() => new JsEngineOptions
         {
-            AllowScriptSlotAnalysis = true,
             DebugMode = true,
             Logger = logger
         });