Merge branch 'refactor/fse-per-call-scheduler-159' into 'main'

refactor(fse): move scheduler to per-call local variable

Closes #159

See merge request arolang/aro!178

Author: KrisSimon

Sources/ARORuntime/Core/FeatureSetExecutor.swift

@@ -23,7 +23,7 @@ import AROParser
 /// By default, statements execute sequentially. When `enableParallelIO`
 /// is true, I/O operations may run in parallel based on data dependencies
 /// while maintaining sequential semantics (ARO-0011).
-public final class FeatureSetExecutor: @unchecked Sendable {
+public final class FeatureSetExecutor: Sendable {
     // MARK: - Properties
 
     private let actionRegistry: ActionRegistry
@@ -32,10 +32,7 @@ public final class FeatureSetExecutor: @unchecked Sendable {
     private let expressionEvaluator: ExpressionEvaluator
 
     /// Whether to enable parallel I/O optimization (ARO-0011)
-    public var enableParallelIO: Bool = false
-
-    /// The statement scheduler for parallel I/O (lazy initialization)
-    private lazy var scheduler = StatementScheduler()
+    public let enableParallelIO: Bool
 
     // MARK: - Initialization
 
@@ -128,6 +125,7 @@ public final class FeatureSetExecutor: @unchecked Sendable {
         do {
             if enableParallelIO {
                 // ARO-0011: Data-flow driven parallel I/O execution
+                let scheduler = StatementScheduler()
                 _ = try await scheduler.execute(
                     analyzedFeatureSet,
                     context: context

Tests/AROuntimeTests/FeatureSetExecutorTests.swift

@@ -36,10 +36,7 @@ struct FeatureSetExecutorTests {
 
     @Test("Enable parallel IO property")
     func testEnableParallelIOProperty() {
-        var executor = createExecutor()
-        #expect(executor.enableParallelIO == false)
-
-        executor.enableParallelIO = true
+        let executor = createExecutor(enableParallelIO: true)
         #expect(executor.enableParallelIO == true)
     }