Honor configured regex timeouts in prepared scripts

CHANGELOG.md

@@ -1,3 +1,9 @@
+# 1.1.3
+
+Released on Friday, October 30 2026.
+
+- Fixed prepared regular-expression literals ignoring the timeout configured during engine creation
+
 # 1.1.2
 
 Released on Sunday, October 25 2026.

src/AngleSharp.Js.Tests/EngineConfigurationTests.cs

@@ -5,6 +5,7 @@ namespace AngleSharp.Js.Tests
     using AngleSharp.Js.Tests.Mocks;
     using AngleSharp.Scripting;
     using Jint;
+    using Jint.Native;
     using Jint.Runtime;
     using NUnit.Framework;
     using System;
@@ -14,6 +15,51 @@ namespace AngleSharp.Js.Tests
 
     public class EngineConfigurationTests
     {
+        [TestCase(false)]
+        [TestCase(true)]
+        public async Task RegexTimeoutAppliesToInlineAndExplicitScripts(Boolean inline)
+        {
+            var timeout = TimeSpan.FromMilliseconds(37);
+            var config = Configuration.Default
+                .With(new EngineCreator((window, options) => new Engine(options.RegexTimeoutInterval(timeout))))
+                .WithJs()
+                .WithEventLoop();
+
+            using (var context = BrowsingContext.New(config))
+            {
+                var document = await context.OpenAsync(request => request.Content(inline
+                    ? "<script>var configuredRegex = /inlineEngineTimeout/;</script>"
+                    : "")).ConfigureAwait(false);
+                var expression = (JsRegExp)document.ExecuteScript(inline ? "configuredRegex" : "/explicitEngineTimeout/");
+
+                Assert.AreEqual(timeout, expression.Value.MatchTimeout);
+            }
+        }
+
+        [TestCase(23, 71)]
+        [TestCase(71, 23)]
+        public async Task CachedScriptsKeepEachEngineRegexTimeout(Int32 firstMilliseconds, Int32 secondMilliseconds)
+        {
+            var source = "/cachedEngineTimeout" + firstMilliseconds + "/";
+
+            foreach (var milliseconds in new[] { firstMilliseconds, secondMilliseconds, firstMilliseconds })
+            {
+                var timeout = TimeSpan.FromMilliseconds(milliseconds);
+                var config = Configuration.Default
+                    .With(new EngineCreator((window, options) => new Engine(options.RegexTimeoutInterval(timeout))))
+                    .WithJs()
+                    .WithEventLoop();
+
+                using (var context = BrowsingContext.New(config))
+                {
+                    var document = await context.OpenNewAsync().ConfigureAwait(false);
+                    var expression = (JsRegExp)document.ExecuteScript(source);
+
+                    Assert.AreEqual(timeout, expression.Value.MatchTimeout);
+                }
+            }
+        }
+
         [Test]
         public async Task ConstraintsAreInstalledBeforeInlineScriptsRun()
         {

src/AngleSharp.Js/Cache/ScriptCache.cs

@@ -9,8 +9,8 @@ namespace AngleSharp.Js.Cache
     /// <summary>
     /// Caches the parsed and analyzed form of scripts. A prepared script is
     /// documented by Jint as reusable and thread-safe, so the same one can serve
-    /// every document that runs the same source - a page loading a library ends up
-    /// parsing it once instead of once per document.
+    /// every document that runs the same source with the same regex timeout - a
+    /// page loading a library ends up parsing it once instead of once per document.
     /// </summary>
     static class ScriptCache
     {
@@ -19,24 +19,29 @@ static class ScriptCache
         //  seen first: libraries are referenced early and by many documents.
         private const Int32 Capacity = 32;
 
-        private static readonly ConcurrentDictionary<String, Prepared<Script>> _scripts =
-            new ConcurrentDictionary<String, Prepared<Script>>(StringComparer.Ordinal);
+        private static readonly ConcurrentDictionary<ScriptKey, Prepared<Script>> _scripts =
+            new ConcurrentDictionary<ScriptKey, Prepared<Script>>();
 
         /// <summary>
         /// Gets the prepared form of the given source. An invalid result means the
         /// source could not be prepared and should be handed to the engine as text,
         /// so that the engine reports the syntax error itself.
         /// </summary>
-        public static Prepared<Script> GetOrCreate(String source)
+        public static Prepared<Script> GetOrCreate(String source, TimeSpan regexTimeout)
         {
-            if (_scripts.TryGetValue(source, out var prepared))
+            var key = new ScriptKey(source, regexTimeout);
+
+            if (_scripts.TryGetValue(key, out var prepared))
             {
                 return prepared;
             }
 
             try
             {
-                prepared = Engine.PrepareScript(source);
+                prepared = Engine.PrepareScript(source, options: new ScriptPreparationOptions
+                {
+                    ParsingOptions = new ScriptParsingOptions { RegexTimeout = regexTimeout },
+                });
             }
             catch (ScriptPreparationException)
             {
@@ -45,10 +50,29 @@ public static Prepared<Script> GetOrCreate(String source)
 
             if (_scripts.Count < Capacity)
             {
-                _scripts.TryAdd(source, prepared);
+                _scripts.TryAdd(key, prepared);
             }
 
             return prepared;
         }
+
+        private readonly struct ScriptKey : IEquatable<ScriptKey>
+        {
+            private readonly String _source;
+            private readonly TimeSpan _regexTimeout;
+
+            public ScriptKey(String source, TimeSpan regexTimeout)
+            {
+                _source = source ?? throw new ArgumentNullException(nameof(source));
+                _regexTimeout = regexTimeout;
+            }
+
+            public Boolean Equals(ScriptKey other) =>
+                String.Equals(_source, other._source, StringComparison.Ordinal) && _regexTimeout == other._regexTimeout;
+
+            public override Boolean Equals(Object obj) => obj is ScriptKey other && Equals(other);
+
+            public override Int32 GetHashCode() => (_source.GetHashCode() * 397) ^ _regexTimeout.GetHashCode();
+        }
     }
 }

src/AngleSharp.Js/EngineInstance.cs

@@ -24,6 +24,7 @@ sealed class EngineInstance
         private const Int32 StackGuardDisabled = -1;
 
         private readonly Engine _engine;
+        private readonly TimeSpan _regexTimeout;
         private readonly PrototypeCache _prototypes;
         private readonly ReferenceCache _references;
         private readonly ConditionalWeakTable<Object, SameObjectCache> _sameObjects;
@@ -49,6 +50,7 @@ public EngineInstance(IWindow window, IDictionary<String, Object> assignments, I
             var creator = window.Document.Context.GetService<EngineCreator>();
             _engine = (creator is null ? new Engine(engineOptions) : creator.Invoke(window, engineOptions))
                 ?? throw new InvalidOperationException("The engine creator must return a Jint engine.");
+            _regexTimeout = engineOptions.Constraints.RegexTimeout;
             _libs = new LibrarySet(libs);
             _prototypes = new PrototypeCache(_engine, _libs);
             _references = new ReferenceCache();
@@ -159,7 +161,7 @@ public JsValue RunScript(String source, String type, String sourceUrl)
             {
                 if (MimeTypeNames.IsJavaScript(type))
                 {
-                    var prepared = ScriptCache.GetOrCreate(source);
+                    var prepared = ScriptCache.GetOrCreate(source, _regexTimeout);
                     //  An invalid result means the source did not parse; hand it to the
                     //  engine as text so the syntax error is reported as usual.
                     return prepared.IsValid ? _engine.Evaluate(prepared) : _engine.Evaluate(source);