chore: update Node versions (#4319)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

src/Misc/externals.sh

@@ -6,8 +6,8 @@ NODE_URL=https://nodejs.org/dist
 NODE_ALPINE_URL=https://github.com/actions/alpine_nodejs/releases/download
 # When you update Node versions you must also create a new release of alpine_nodejs at that updated version.
 # Follow the instructions here: https://github.com/actions/alpine_nodejs?tab=readme-ov-file#getting-started
-NODE20_VERSION="20.20.1"
-NODE24_VERSION="24.14.0"
+NODE20_VERSION="20.20.2"
+NODE24_VERSION="24.14.1"
 
 get_abs_path() {
   # exploits the fact that pwd will print abs path when no args

src/Runner.Worker/ActionManifestManager.cs

@@ -316,7 +316,6 @@ namespace GitHub.Runner.Worker
                 Schema = _actionManifestSchema,
                 // TODO: Switch to real tracewriter for cutover
                 TraceWriter = new GitHub.Actions.WorkflowParser.ObjectTemplating.EmptyTraceWriter(),
-                AllowCaseFunction = false,
             };
 
             // Expression values from execution context

src/Runner.Worker/ActionManifestManagerLegacy.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Threading;
@@ -315,7 +315,6 @@ namespace GitHub.Runner.Worker
                     maxBytes: 10 * 1024 * 1024),
                 Schema = _actionManifestSchema,
                 TraceWriter = executionContext.ToTemplateTraceWriter(),
-                AllowCaseFunction = false,
             };
 
             // Expression values from execution context

src/Runner.Worker/Dap/DapDebugger.cs

@@ -1,9 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.IO;
 using System.Net;
-using System.Net.Http.Headers;
 using System.Net.Sockets;
 using System.Text;
 using System.Threading;
@@ -11,9 +9,6 @@ using System.Threading.Tasks;
 using GitHub.DistributedTask.WebApi;
 using GitHub.Runner.Common;
 using GitHub.Runner.Sdk;
-using Microsoft.DevTunnels.Connections;
-using Microsoft.DevTunnels.Contracts;
-using Microsoft.DevTunnels.Management;
 using Newtonsoft.Json;
 
 namespace GitHub.Runner.Worker.Dap
@@ -35,7 +30,9 @@ namespace GitHub.Runner.Worker.Dap
     /// </summary>
     public sealed class DapDebugger : RunnerService, IDapDebugger
     {
+        private const int _defaultPort = 4711;
         private const int _defaultTimeoutMinutes = 15;
+        private const string _portEnvironmentVariable = "ACTIONS_RUNNER_DAP_PORT";
         private const string _timeoutEnvironmentVariable = "ACTIONS_RUNNER_DAP_CONNECTION_TIMEOUT";
         private const string _contentLengthHeader = "Content-Length: ";
         private const int _maxMessageSize = 10 * 1024 * 1024; // 10 MB
@@ -61,12 +58,6 @@ namespace GitHub.Runner.Worker.Dap
         private CancellationTokenRegistration? _cancellationRegistration;
         private bool _isFirstStep = true;
 
-        // Dev Tunnel relay host for remote debugging
-        private TunnelRelayTunnelHost _tunnelRelayHost;
-
-        // When true, skip tunnel relay startup (unit tests only)
-        internal bool SkipTunnelRelay { get; set; }
-
         // Synchronization for step execution
         private TaskCompletionSource<DapCommand> _commandTcs;
         private readonly object _stateLock = new object();
@@ -110,18 +101,11 @@ namespace GitHub.Runner.Worker.Dap
             Trace.Info("DapDebugger initialized");
         }
 
-        public async Task StartAsync(IExecutionContext jobContext)
+        public Task StartAsync(IExecutionContext jobContext)
         {
             ArgUtil.NotNull(jobContext, nameof(jobContext));
-            var debuggerConfig = jobContext.Global.Debugger;
+            var port = ResolvePort();
 
-            if (debuggerConfig == null || !debuggerConfig.HasValidTunnel)
-            {
-                throw new InvalidOperationException(
-                    "Debugger requires valid tunnel configuration (tunnelId, clusterId, hostToken, port).");
-            }
-
-            var port = debuggerConfig.Tunnel.Port;
             Trace.Info($"Starting DAP debugger on port {port}");
 
             _jobContext = jobContext;
@@ -131,15 +115,6 @@ namespace GitHub.Runner.Worker.Dap
             _listener.Start();
             Trace.Info($"DAP debugger listening on {_listener.LocalEndpoint}");
 
-            // Start Dev Tunnel relay so remote clients reach the local DAP port.
-            // The relay is torn down explicitly in StopAsync (after the DAP session
-            // is closed) so we do NOT pass the job cancellation token here — that
-            // would race with the DAP shutdown and drop the transport mid-protocol.
-            if (!SkipTunnelRelay)
-            {
-                await StartTunnelRelayAsync(debuggerConfig);
-            }
-
             _state = DapSessionState.WaitingForConnection;
             _connectionLoopTask = ConnectionLoopAsync(jobContext.CancellationToken);
 
@@ -151,36 +126,7 @@ namespace GitHub.Runner.Worker.Dap
             });
 
             Trace.Info($"DAP debugger started on port {port}");
-        }
-
-        private async Task StartTunnelRelayAsync(DebuggerConfig config)
-        {
-            Trace.Info($"Starting Dev Tunnel relay (tunnel={config.Tunnel.TunnelId}, cluster={config.Tunnel.ClusterId})");
-
-            var managementClient = new TunnelManagementClient(
-                new ProductInfoHeaderValue("actions-runner", "1.0"),
-                () => Task.FromResult(
-                    (AuthenticationHeaderValue)
-                    new AuthenticationHeaderValue("tunnel", config.Tunnel.HostToken)));
-
-            var tunnel = new Tunnel
-            {
-                TunnelId = config.Tunnel.TunnelId,
-                ClusterId = config.Tunnel.ClusterId,
-                AccessTokens = new Dictionary<string, string>
-                {
-                    [TunnelAccessScopes.Host] = config.Tunnel.HostToken
-                },
-                Ports = new[]
-                {
-                    new TunnelPort { PortNumber = (ushort)config.Tunnel.Port }
-                },
-            };
-
-            _tunnelRelayHost = new TunnelRelayTunnelHost(managementClient, new TraceSource("DevTunnelRelay"));
-            await _tunnelRelayHost.StartAsync(tunnel, CancellationToken.None);
-
-            Trace.Info("Dev Tunnel relay started");
+            return Task.CompletedTask;
         }
 
         public async Task WaitUntilReadyAsync()
@@ -253,25 +199,6 @@ namespace GitHub.Runner.Worker.Dap
                         }
                         catch { /* best effort */ }
                     }
-
-                    // Tear down Dev Tunnel relay
-                    if (_tunnelRelayHost != null)
-                    {
-                        try
-                        {
-                            Trace.Info("Stopping Dev Tunnel relay");
-                            await _tunnelRelayHost.DisposeAsync();
-                            Trace.Info("Dev Tunnel relay stopped");
-                        }
-                        catch (Exception ex)
-                        {
-                            Trace.Warning($"Error stopping tunnel relay: {ex.Message}");
-                        }
-                        finally
-                        {
-                            _tunnelRelayHost = null;
-                        }
-                    }
                 }
                 catch (Exception ex)
                 {
@@ -1345,6 +1272,18 @@ namespace GitHub.Runner.Worker.Dap
             };
         }
 
+        internal int ResolvePort()
+        {
+            var portEnv = Environment.GetEnvironmentVariable(_portEnvironmentVariable);
+            if (!string.IsNullOrEmpty(portEnv) && int.TryParse(portEnv, out var customPort) && customPort > 1024 && customPort <= 65535)
+            {
+                Trace.Info($"Using custom DAP port {customPort} from {_portEnvironmentVariable}");
+                return customPort;
+            }
+
+            return _defaultPort;
+        }
+
         internal int ResolveTimeout()
         {
             var timeoutEnv = Environment.GetEnvironmentVariable(_timeoutEnvironmentVariable);

src/Runner.Worker/Dap/DebuggerConfig.cs

@@ -1,33 +0,0 @@
-using GitHub.DistributedTask.Pipelines;
-
-namespace GitHub.Runner.Worker.Dap
-{
-    /// <summary>
-    /// Consolidated runtime configuration for the job debugger.
-    /// Populated once from the acquire response and owned by <see cref="GlobalContext"/>.
-    /// </summary>
-    public sealed class DebuggerConfig
-    {
-        public DebuggerConfig(bool enabled, DebuggerTunnelInfo tunnel)
-        {
-            Enabled = enabled;
-            Tunnel = tunnel;
-        }
-
-        /// <summary>Whether the debugger is enabled for this job.</summary>
-        public bool Enabled { get; }
-
-        /// <summary>
-        /// Dev Tunnel details for remote debugging.
-        /// Required when <see cref="Enabled"/> is true.
-        /// </summary>
-        public DebuggerTunnelInfo Tunnel { get; }
-
-        /// <summary>Whether the tunnel configuration is complete and valid.</summary>
-        public bool HasValidTunnel => Tunnel != null
-            && !string.IsNullOrEmpty(Tunnel.TunnelId)
-            && !string.IsNullOrEmpty(Tunnel.ClusterId)
-            && !string.IsNullOrEmpty(Tunnel.HostToken)
-            && Tunnel.Port > 0;
-    }
-}

src/Runner.Worker/ExecutionContext.cs

@@ -970,7 +970,7 @@ namespace GitHub.Runner.Worker
             Global.WriteDebug = Global.Variables.Step_Debug ?? false;
 
             // Debugger enabled flag (from acquire response).
-            Global.Debugger = new Dap.DebuggerConfig(message.EnableDebugger, message.DebuggerTunnel);
+            Global.EnableDebugger = message.EnableDebugger;
 
             // Hook up JobServerQueueThrottling event, we will log warning on server tarpit.
             _jobServerQueue.JobServerQueueThrottling += JobServerQueueThrottling_EventReceived;

src/Runner.Worker/GlobalContext.cs

@@ -4,7 +4,6 @@ using GitHub.Actions.RunService.WebApi;
 using GitHub.DistributedTask.WebApi;
 using GitHub.Runner.Common.Util;
 using GitHub.Runner.Worker.Container;
-using GitHub.Runner.Worker.Dap;
 using Newtonsoft.Json.Linq;
 using Sdk.RSWebApi.Contracts;
 
@@ -28,7 +27,7 @@ namespace GitHub.Runner.Worker
         public StepsContext StepsContext { get; set; }
         public Variables Variables { get; set; }
         public bool WriteDebug { get; set; }
-        public DebuggerConfig Debugger { get; set; }
+        public bool EnableDebugger { get; set; }
         public string InfrastructureFailureCategory { get; set; }
         public JObject ContainerHookState { get; set; }
         public bool HasTemplateEvaluatorMismatch { get; set; }

src/Runner.Worker/JobRunner.cs

@@ -182,7 +182,7 @@ namespace GitHub.Runner.Worker
                 _tempDirectoryManager.InitializeTempDirectory(jobContext);
 
                 // Setup the debugger
-                if (jobContext.Global.Debugger?.Enabled == true)
+                if (jobContext.Global.EnableDebugger)
                 {
                     Trace.Info("Debugger enabled for this job run");
 

src/Runner.Worker/Runner.Worker.csproj

@@ -23,7 +23,6 @@
     <PackageReference Include="System.ServiceProcess.ServiceController" Version="8.0.1" />
     <PackageReference Include="System.Threading.Channels" Version="8.0.0" />
     <PackageReference Include="YamlDotNet.Signed" Version="5.3.0" />
-    <PackageReference Include="Microsoft.DevTunnels.Connections" Version="1.0.7317" />
   </ItemGroup>
 
   <ItemGroup>

src/Sdk/DTExpressions2/Expressions2/ExpressionParser.cs

@@ -17,10 +17,9 @@ namespace GitHub.DistributedTask.Expressions2
             String expression,
             ITraceWriter trace,
             IEnumerable<INamedValueInfo> namedValues,
-            IEnumerable<IFunctionInfo> functions,
-            Boolean allowCaseFunction = true)
+            IEnumerable<IFunctionInfo> functions)
         {
-            var context = new ParseContext(expression, trace, namedValues, functions, allowCaseFunction: allowCaseFunction);
+            var context = new ParseContext(expression, trace, namedValues, functions);
             context.Trace.Info($"Parsing expression: <{expression}>");
             return CreateTree(context);
         }
@@ -416,12 +415,6 @@ namespace GitHub.DistributedTask.Expressions2
             String name,
             out IFunctionInfo functionInfo)
         {
-            if (String.Equals(name, "case", StringComparison.OrdinalIgnoreCase) && !context.AllowCaseFunction)
-            {
-                functionInfo = null;
-                return false;
-            }
-
             return ExpressionConstants.WellKnownFunctions.TryGetValue(name, out functionInfo) ||
                 context.ExtensionFunctions.TryGetValue(name, out functionInfo);
         }
@@ -429,7 +422,6 @@ namespace GitHub.DistributedTask.Expressions2
         private sealed class ParseContext
         {
             public Boolean AllowUnknownKeywords;
-            public Boolean AllowCaseFunction;
             public readonly String Expression;
             public readonly Dictionary<String, IFunctionInfo> ExtensionFunctions = new Dictionary<String, IFunctionInfo>(StringComparer.OrdinalIgnoreCase);
             public readonly Dictionary<String, INamedValueInfo> ExtensionNamedValues = new Dictionary<String, INamedValueInfo>(StringComparer.OrdinalIgnoreCase);
@@ -445,8 +437,7 @@ namespace GitHub.DistributedTask.Expressions2
                 ITraceWriter trace,
                 IEnumerable<INamedValueInfo> namedValues,
                 IEnumerable<IFunctionInfo> functions,
-                Boolean allowUnknownKeywords = false,
-                Boolean allowCaseFunction = true)
+                Boolean allowUnknownKeywords = false)
             {
                 Expression = expression ?? String.Empty;
                 if (Expression.Length > ExpressionConstants.MaxLength)
@@ -467,7 +458,6 @@ namespace GitHub.DistributedTask.Expressions2
 
                 LexicalAnalyzer = new LexicalAnalyzer(Expression);
                 AllowUnknownKeywords = allowUnknownKeywords;
-                AllowCaseFunction = allowCaseFunction;
             }
 
             private class NoOperationTraceWriter : ITraceWriter

src/Sdk/DTObjectTemplating/ObjectTemplating/TemplateContext.cs

@@ -86,12 +86,6 @@ namespace GitHub.DistributedTask.ObjectTemplating
 
         internal ITraceWriter TraceWriter { get; set; }
 
-        /// <summary>
-        /// Gets or sets a value indicating whether the case expression function is allowed.
-        /// Defaults to true. Set to false to disable the case function.
-        /// </summary>
-        internal Boolean AllowCaseFunction { get; set; } = true;
-
         private IDictionary<String, Int32> FileIds
         {
             get

src/Sdk/DTObjectTemplating/ObjectTemplating/Tokens/TemplateToken.cs

@@ -57,7 +57,7 @@ namespace GitHub.DistributedTask.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,
@@ -94,7 +94,7 @@ namespace GitHub.DistributedTask.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,
@@ -123,7 +123,7 @@ namespace GitHub.DistributedTask.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,
@@ -152,7 +152,7 @@ namespace GitHub.DistributedTask.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,

src/Sdk/DTPipelines/Pipelines/AgentJobRequestMessage.cs

@@ -260,13 +260,6 @@ namespace GitHub.DistributedTask.Pipelines
             set;
         }
 
-        [DataMember(EmitDefaultValue = false)]
-        public DebuggerTunnelInfo DebuggerTunnel
-        {
-            get;
-            set;
-        }
-
         /// <summary>
         /// Gets the collection of variables associated with the current context.
         /// </summary>

src/Sdk/DTPipelines/Pipelines/DebuggerTunnelInfo.cs

@@ -1,24 +0,0 @@
-using System.Runtime.Serialization;
-
-namespace GitHub.DistributedTask.Pipelines
-{
-    /// <summary>
-    /// Dev Tunnel information the runner needs to host the debugger tunnel.
-    /// Matches the run-service <c>DebuggerTunnel</c> contract.
-    /// </summary>
-    [DataContract]
-    public sealed class DebuggerTunnelInfo
-    {
-        [DataMember(EmitDefaultValue = false)]
-        public string TunnelId { get; set; }
-
-        [DataMember(EmitDefaultValue = false)]
-        public string ClusterId { get; set; }
-
-        [DataMember(EmitDefaultValue = false)]
-        public string HostToken { get; set; }
-
-        [DataMember(EmitDefaultValue = false)]
-        public int Port { get; set; }
-    }
-}

src/Sdk/DTPipelines/Pipelines/ObjectTemplating/PipelineTemplateConverter.cs

@@ -681,7 +681,7 @@ namespace GitHub.DistributedTask.Pipelines.ObjectTemplating
             var node = default(ExpressionNode);
             try
             {
-                node = expressionParser.CreateTree(condition, null, namedValues, functions, allowCaseFunction: context.AllowCaseFunction) as ExpressionNode;
+                node = expressionParser.CreateTree(condition, null, namedValues, functions) as ExpressionNode;
             }
             catch (Exception ex)
             {

src/Sdk/Expressions/ExpressionParser.cs

@@ -1,4 +1,4 @@
-#nullable disable // Consider removing in the future to minimize likelihood of NullReferenceException; refer https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references
+#nullable disable // Consider removing in the future to minimize likelihood of NullReferenceException; refer https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references
 
 using System;
 using System.Collections.Generic;
@@ -17,10 +17,9 @@ namespace GitHub.Actions.Expressions
             String expression,
             ITraceWriter trace,
             IEnumerable<INamedValueInfo> namedValues,
-            IEnumerable<IFunctionInfo> functions,
-            Boolean allowCaseFunction = true)
+            IEnumerable<IFunctionInfo> functions)
         {
-            var context = new ParseContext(expression, trace, namedValues, functions, allowCaseFunction: allowCaseFunction);
+            var context = new ParseContext(expression, trace, namedValues, functions);
             context.Trace.Info($"Parsing expression: <{expression}>");
             return CreateTree(context);
         }
@@ -322,7 +321,7 @@ namespace GitHub.Actions.Expressions
                     context.Operators.Pop();
                 }
                 var functionOperands = PopOperands(context, parameterCount);
-                
+
                 // Node already exists on the operand stack
                 function = (Function)context.Operands.Peek();
 
@@ -416,12 +415,6 @@ namespace GitHub.Actions.Expressions
             String name,
             out IFunctionInfo functionInfo)
         {
-            if (String.Equals(name, "case", StringComparison.OrdinalIgnoreCase) && !context.AllowCaseFunction)
-            {
-                functionInfo = null;
-                return false;
-            }
-
             return ExpressionConstants.WellKnownFunctions.TryGetValue(name, out functionInfo) ||
                 context.ExtensionFunctions.TryGetValue(name, out functionInfo);
         }
@@ -429,7 +422,6 @@ namespace GitHub.Actions.Expressions
         private sealed class ParseContext
         {
             public Boolean AllowUnknownKeywords;
-            public Boolean AllowCaseFunction;
             public readonly String Expression;
             public readonly Dictionary<String, IFunctionInfo> ExtensionFunctions = new Dictionary<String, IFunctionInfo>(StringComparer.OrdinalIgnoreCase);
             public readonly Dictionary<String, INamedValueInfo> ExtensionNamedValues = new Dictionary<String, INamedValueInfo>(StringComparer.OrdinalIgnoreCase);
@@ -445,8 +437,7 @@ namespace GitHub.Actions.Expressions
                 ITraceWriter trace,
                 IEnumerable<INamedValueInfo> namedValues,
                 IEnumerable<IFunctionInfo> functions,
-                Boolean allowUnknownKeywords = false,
-                Boolean allowCaseFunction = true)
+                Boolean allowUnknownKeywords = false)
             {
                 Expression = expression ?? String.Empty;
                 if (Expression.Length > ExpressionConstants.MaxLength)
@@ -467,7 +458,6 @@ namespace GitHub.Actions.Expressions
 
                 LexicalAnalyzer = new LexicalAnalyzer(Expression);
                 AllowUnknownKeywords = allowUnknownKeywords;
-                AllowCaseFunction = allowCaseFunction;
             }
 
             private class NoOperationTraceWriter : ITraceWriter

src/Sdk/WorkflowParser/Conversion/WorkflowTemplateConverter.cs

@@ -1828,7 +1828,7 @@ namespace GitHub.Actions.WorkflowParser.Conversion
             var node = default(ExpressionNode);
             try
             {
-                node = expressionParser.CreateTree(condition, null, namedValues, functions, allowCaseFunction: context.AllowCaseFunction) as ExpressionNode;
+                node = expressionParser.CreateTree(condition, null, namedValues, functions) as ExpressionNode;
             }
             catch (Exception ex)
             {

src/Sdk/WorkflowParser/ObjectTemplating/TemplateContext.cs

@@ -1,4 +1,4 @@
-#nullable disable // Consider removing in the future to minimize likelihood of NullReferenceException; refer https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references
+#nullable disable // Consider removing in the future to minimize likelihood of NullReferenceException; refer https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references
 
 using System;
 using System.Collections.Generic;
@@ -113,12 +113,6 @@ namespace GitHub.Actions.WorkflowParser.ObjectTemplating
         /// </summary>
         internal Boolean StrictJsonParsing { get; set; }
 
-        /// <summary>
-        /// Gets or sets a value indicating whether the case expression function is allowed.
-        /// Defaults to true. Set to false to disable the case function.
-        /// </summary>
-        internal Boolean AllowCaseFunction { get; set; } = true;
-
         internal ITraceWriter TraceWriter { get; set; }
 
         private IDictionary<String, Int32> FileIds

src/Sdk/WorkflowParser/ObjectTemplating/Tokens/TemplateToken.cs

@@ -1,4 +1,4 @@
-#nullable disable // Consider removing in the future to minimize likelihood of NullReferenceException; refer https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references
+#nullable disable // Consider removing in the future to minimize likelihood of NullReferenceException; refer https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references
 
 using System;
 using System.Collections.Generic;
@@ -55,7 +55,7 @@ namespace GitHub.Actions.WorkflowParser.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,
@@ -93,7 +93,7 @@ namespace GitHub.Actions.WorkflowParser.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,
@@ -123,7 +123,7 @@ namespace GitHub.Actions.WorkflowParser.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,
@@ -153,7 +153,7 @@ namespace GitHub.Actions.WorkflowParser.ObjectTemplating.Tokens
             var originalBytes = context.Memory.CurrentBytes;
             try
             {
-                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions, allowCaseFunction: context.AllowCaseFunction);
+                var tree = new ExpressionParser().CreateTree(expression, null, context.GetExpressionNamedValues(), context.ExpressionFunctions);
                 var options = new EvaluationOptions
                 {
                     MaxMemory = context.Memory.MaxBytes,
@@ -289,4 +289,4 @@ namespace GitHub.Actions.WorkflowParser.ObjectTemplating.Tokens
             return result;
         }
     }
-}
+}

src/Test/L0/Sdk/ExpressionParserL0.cs

@@ -1,4 +1,4 @@
-using GitHub.DistributedTask.Expressions2;
+using GitHub.DistributedTask.Expressions2;
 using GitHub.DistributedTask.Expressions2.Sdk;
 using GitHub.DistributedTask.ObjectTemplating;
 using System;
@@ -9,7 +9,7 @@ namespace GitHub.Runner.Common.Tests.Sdk
 {
     /// <summary>
     /// Regression tests for ExpressionParser.CreateTree to verify that
-    /// allowCaseFunction does not accidentally set allowUnknownKeywords.
+    /// the case function does not accidentally set allowUnknownKeywords.
     /// </summary>
     public sealed class ExpressionParserL0
     {
@@ -18,7 +18,7 @@ namespace GitHub.Runner.Common.Tests.Sdk
         [Trait("Category", "Sdk")]
         public void CreateTree_RejectsUnrecognizedNamedValue()
         {
-            // Regression: allowCaseFunction was passed positionally into
+            // Regression: the case function parameter was passed positionally into
             // the allowUnknownKeywords parameter, causing all named values
             // to be silently accepted.
             var parser = new ExpressionParser();
@@ -52,7 +52,7 @@ namespace GitHub.Runner.Common.Tests.Sdk
         [Fact]
         [Trait("Level", "L0")]
         [Trait("Category", "Sdk")]
-        public void CreateTree_CaseFunctionWorks_WhenAllowed()
+        public void CreateTree_CaseFunctionWorks()
         {
             var parser = new ExpressionParser();
             var namedValues = new List<INamedValueInfo>
@@ -60,35 +60,17 @@ namespace GitHub.Runner.Common.Tests.Sdk
                 new NamedValueInfo<ContextValueNode>("github"),
             };
 
-            var node = parser.CreateTree("case(github.event_name, 'push', 'Push Event')", null, namedValues, null, allowCaseFunction: true);
+            var node = parser.CreateTree("case(github.event_name, 'push', 'Push Event')", null, namedValues, null);
 
             Assert.NotNull(node);
         }
 
-        [Fact]
-        [Trait("Level", "L0")]
-        [Trait("Category", "Sdk")]
-        public void CreateTree_CaseFunctionRejected_WhenDisallowed()
-        {
-            var parser = new ExpressionParser();
-            var namedValues = new List<INamedValueInfo>
-            {
-                new NamedValueInfo<ContextValueNode>("github"),
-            };
-
-            var ex = Assert.Throws<ParseException>(() =>
-                parser.CreateTree("case(github.event_name, 'push', 'Push Event')", null, namedValues, null, allowCaseFunction: false));
-
-            Assert.Contains("Unrecognized function", ex.Message);
-        }
-
         [Fact]
         [Trait("Level", "L0")]
         [Trait("Category", "Sdk")]
         public void CreateTree_CaseFunctionDoesNotAffectUnknownKeywords()
         {
-            // The key regression test: with allowCaseFunction=true (default),
-            // unrecognized named values must still be rejected.
+            // The key regression test: unrecognized named values must still be rejected.
             var parser = new ExpressionParser();
             var namedValues = new List<INamedValueInfo>
             {
@@ -96,7 +78,7 @@ namespace GitHub.Runner.Common.Tests.Sdk
             };
 
             var ex = Assert.Throws<ParseException>(() =>
-                parser.CreateTree("github.ref", null, namedValues, null, allowCaseFunction: true));
+                parser.CreateTree("github.ref", null, namedValues, null));
 
             Assert.Contains("Unrecognized named-value", ex.Message);
         }

src/Test/L0/Sdk/RSWebApi/AgentJobRequestMessageL0.cs

@@ -69,56 +69,6 @@ public sealed class AgentJobRequestMessageL0
         Assert.False(recoveredMessage.EnableDebugger, "EnableDebugger should be false when JSON contains 'EnableDebugger': false");
     }
 
-    [Fact]
-    [Trait("Level", "L0")]
-    [Trait("Category", "Common")]
-    public void VerifyDebuggerTunnelDeserialization_WithTunnel()
-    {
-        // Arrange
-        var serializer = new DataContractJsonSerializer(typeof(AgentJobRequestMessage), new DataContractJsonSerializerSettings
-        {
-            KnownTypes = new[] { typeof(DebuggerTunnelInfo) }
-        });
-        string json = DoubleQuotify(
-            "{'EnableDebugger': true, 'DebuggerTunnel': {'TunnelId': 'tun-123', 'ClusterId': 'use2', 'HostToken': 'tok-abc', 'Port': 4711}}");
-
-        // Act
-        using var stream = new MemoryStream();
-        stream.Write(Encoding.UTF8.GetBytes(json));
-        stream.Position = 0;
-        var recoveredMessage = serializer.ReadObject(stream) as AgentJobRequestMessage;
-
-        // Assert
-        Assert.NotNull(recoveredMessage);
-        Assert.True(recoveredMessage.EnableDebugger);
-        Assert.NotNull(recoveredMessage.DebuggerTunnel);
-        Assert.Equal("tun-123", recoveredMessage.DebuggerTunnel.TunnelId);
-        Assert.Equal("use2", recoveredMessage.DebuggerTunnel.ClusterId);
-        Assert.Equal("tok-abc", recoveredMessage.DebuggerTunnel.HostToken);
-        Assert.Equal(4711, recoveredMessage.DebuggerTunnel.Port);
-    }
-
-    [Fact]
-    [Trait("Level", "L0")]
-    [Trait("Category", "Common")]
-    public void VerifyDebuggerTunnelDeserialization_WithoutTunnel()
-    {
-        // Arrange
-        var serializer = new DataContractJsonSerializer(typeof(AgentJobRequestMessage));
-        string json = DoubleQuotify("{'EnableDebugger': true}");
-
-        // Act
-        using var stream = new MemoryStream();
-        stream.Write(Encoding.UTF8.GetBytes(json));
-        stream.Position = 0;
-        var recoveredMessage = serializer.ReadObject(stream) as AgentJobRequestMessage;
-
-        // Assert
-        Assert.NotNull(recoveredMessage);
-        Assert.True(recoveredMessage.EnableDebugger);
-        Assert.Null(recoveredMessage.DebuggerTunnel);
-    }
-
     private static string DoubleQuotify(string text)
     {
         return text.Replace('\'', '"');

src/Test/L0/Worker/ActionManifestManagerL0.cs

@@ -504,7 +504,7 @@ namespace GitHub.Runner.Common.Tests.Worker
             }
         }
 
-         [Fact]
+        [Fact]
         [Trait("Level", "L0")]
         [Trait("Category", "Worker")]
         public void Load_Node24Action()
@@ -1006,6 +1006,45 @@ namespace GitHub.Runner.Common.Tests.Worker
             _ec.Setup(x => x.AddIssue(It.IsAny<Issue>(), It.IsAny<ExecutionContextLogOptions>())).Callback((Issue issue, ExecutionContextLogOptions logOptions) => { _hc.GetTrace().Info($"[{issue.Type}]{logOptions.LogMessageOverride ?? issue.Message}"); });
         }
 
+        [Fact]
+        [Trait("Level", "L0")]
+        [Trait("Category", "Worker")]
+        public void Evaluate_Default_Input_Case_Function()
+        {
+            try
+            {
+                //Arrange
+                Setup();
+
+                var actionManifest = new ActionManifestManager();
+                actionManifest.Initialize(_hc);
+
+                _ec.Object.ExpressionValues["github"] = new LegacyContextData.DictionaryContextData
+                {
+                    { "ref", new LegacyContextData.StringContextData("refs/heads/main") },
+                };
+                _ec.Object.ExpressionValues["strategy"] = new LegacyContextData.DictionaryContextData();
+                _ec.Object.ExpressionValues["matrix"] = new LegacyContextData.DictionaryContextData();
+                _ec.Object.ExpressionValues["steps"] = new LegacyContextData.DictionaryContextData();
+                _ec.Object.ExpressionValues["job"] = new LegacyContextData.DictionaryContextData();
+                _ec.Object.ExpressionValues["runner"] = new LegacyContextData.DictionaryContextData();
+                _ec.Object.ExpressionValues["env"] = new LegacyContextData.DictionaryContextData();
+                _ec.Object.ExpressionFunctions.Add(new LegacyExpressions.FunctionInfo<GitHub.Runner.Worker.Expressions.HashFilesFunction>("hashFiles", 1, 255));
+
+                // Act — evaluate a case() expression as a default input value.
+                // The feature flag is set, so this should succeed.
+                var token = new BasicExpressionToken(null, null, null, "case(true, 'matched', 'default')");
+                var result = actionManifest.EvaluateDefaultInput(_ec.Object, "testInput", token);
+
+                // Assert — case() should evaluate successfully
+                Assert.Equal("matched", result);
+            }
+            finally
+            {
+                Teardown();
+            }
+        }
+
         private void Teardown()
         {
             _hc?.Dispose();

src/Test/L0/Worker/DapDebuggerL0.cs

@@ -16,6 +16,7 @@ namespace GitHub.Runner.Common.Tests.Worker
 {
     public sealed class DapDebuggerL0
     {
+        private const string PortEnvironmentVariable = "ACTIONS_RUNNER_DAP_PORT";
         private const string TimeoutEnvironmentVariable = "ACTIONS_RUNNER_DAP_CONNECTION_TIMEOUT";
         private DapDebugger _debugger;
 
@@ -24,7 +25,6 @@ namespace GitHub.Runner.Common.Tests.Worker
             var hc = new TestHostContext(this, testName);
             _debugger = new DapDebugger();
             _debugger.Initialize(hc);
-            _debugger.SkipTunnelRelay = true;
             return hc;
         }
 
@@ -144,26 +144,6 @@ namespace GitHub.Runner.Common.Tests.Worker
         {
             var jobContext = new Mock<IExecutionContext>();
             jobContext.Setup(x => x.CancellationToken).Returns(cancellationToken);
-            jobContext.Setup(x => x.Global).Returns(new GlobalContext());
-            jobContext
-                .Setup(x => x.GetGitHubContext(It.IsAny<string>()))
-                .Returns((string contextName) => string.Equals(contextName, "job", StringComparison.Ordinal) ? jobName : null);
-            return jobContext;
-        }
-
-        private static Mock<IExecutionContext> CreateJobContextWithTunnel(CancellationToken cancellationToken, int port, string jobName = null)
-        {
-            var tunnel = new GitHub.DistributedTask.Pipelines.DebuggerTunnelInfo
-            {
-                TunnelId = "test-tunnel",
-                ClusterId = "test-cluster",
-                HostToken = "test-token",
-                Port = port
-            };
-            var debuggerConfig = new DebuggerConfig(true, tunnel);
-            var jobContext = new Mock<IExecutionContext>();
-            jobContext.Setup(x => x.CancellationToken).Returns(cancellationToken);
-            jobContext.Setup(x => x.Global).Returns(new GlobalContext { Debugger = debuggerConfig });
             jobContext
                 .Setup(x => x.GetGitHubContext(It.IsAny<string>()))
                 .Returns((string contextName) => string.Equals(contextName, "job", StringComparison.Ordinal) ? jobName : null);
@@ -185,36 +165,42 @@ namespace GitHub.Runner.Common.Tests.Worker
         [Fact]
         [Trait("Level", "L0")]
         [Trait("Category", "Worker")]
-        public async Task StartAsyncFailsWithoutValidTunnelConfig()
+        public void ResolvePortUsesCustomPortFromEnvironment()
         {
             using (CreateTestContext())
             {
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = new Mock<IExecutionContext>();
-                jobContext.Setup(x => x.CancellationToken).Returns(cts.Token);
-                jobContext.Setup(x => x.Global).Returns(new GlobalContext
+                WithEnvironmentVariable(PortEnvironmentVariable, "9999", () =>
                 {
-                    Debugger = new DebuggerConfig(true, null)
+                    Assert.Equal(9999, _debugger.ResolvePort());
                 });
-
-                await Assert.ThrowsAsync<InvalidOperationException>(() => _debugger.StartAsync(jobContext.Object));
             }
         }
 
         [Fact]
         [Trait("Level", "L0")]
         [Trait("Category", "Worker")]
-        public async Task StartAsyncUsesPortFromTunnelConfig()
+        public void ResolvePortIgnoresInvalidPortFromEnvironment()
         {
             using (CreateTestContext())
             {
-                var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-                using var client = await ConnectClientAsync(port);
-                Assert.True(client.Connected);
-                await _debugger.StopAsync();
+                WithEnvironmentVariable(PortEnvironmentVariable, "not-a-number", () =>
+                {
+                    Assert.Equal(4711, _debugger.ResolvePort());
+                });
+            }
+        }
+
+        [Fact]
+        [Trait("Level", "L0")]
+        [Trait("Category", "Worker")]
+        public void ResolvePortIgnoresOutOfRangePortFromEnvironment()
+        {
+            using (CreateTestContext())
+            {
+                WithEnvironmentVariable(PortEnvironmentVariable, "99999", () =>
+                {
+                    Assert.Equal(4711, _debugger.ResolvePort());
+                });
             }
         }
 
@@ -268,12 +254,15 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-                using var client = await ConnectClientAsync(port);
-                Assert.True(client.Connected);
-                await _debugger.StopAsync();
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
+                {
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
+                    using var client = await ConnectClientAsync(port);
+                    Assert.True(client.Connected);
+                    await _debugger.StopAsync();
+                });
             }
         }
 
@@ -286,10 +275,13 @@ namespace GitHub.Runner.Common.Tests.Worker
             {
                 foreach (var port in new[] { GetFreePort(), GetFreePort() })
                 {
-                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                    var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                    await _debugger.StartAsync(jobContext.Object);
-                    await _debugger.StopAsync();
+                    await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
+                    {
+                        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                        var jobContext = CreateJobContext(cts.Token);
+                        await _debugger.StartAsync(jobContext.Object);
+                        await _debugger.StopAsync();
+                    });
                 }
             }
         }
@@ -302,22 +294,25 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-
-                var waitTask = _debugger.WaitUntilReadyAsync();
-                using var client = await ConnectClientAsync(port);
-                await SendRequestAsync(client.GetStream(), new Request
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
                 {
-                    Seq = 1,
-                    Type = "request",
-                    Command = "configurationDone"
-                });
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
 
-                await waitTask;
-                Assert.Equal(DapSessionState.Ready, _debugger.State);
-                await _debugger.StopAsync();
+                    var waitTask = _debugger.WaitUntilReadyAsync();
+                    using var client = await ConnectClientAsync(port);
+                    await SendRequestAsync(client.GetStream(), new Request
+                    {
+                        Seq = 1,
+                        Type = "request",
+                        Command = "configurationDone"
+                    });
+
+                    await waitTask;
+                    Assert.Equal(DapSessionState.Ready, _debugger.State);
+                    await _debugger.StopAsync();
+                });
             }
         }
 
@@ -329,22 +324,25 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port, "ci-job");
-                await _debugger.StartAsync(jobContext.Object);
-                using var client = await ConnectClientAsync(port);
-                var stream = client.GetStream();
-                await SendRequestAsync(client.GetStream(), new Request
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
                 {
-                    Seq = 1,
-                    Type = "request",
-                    Command = "threads"
-                });
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token, "ci-job");
+                    await _debugger.StartAsync(jobContext.Object);
+                    using var client = await ConnectClientAsync(port);
+                    var stream = client.GetStream();
+                    await SendRequestAsync(client.GetStream(), new Request
+                    {
+                        Seq = 1,
+                        Type = "request",
+                        Command = "threads"
+                    });
 
-                var response = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
-                Assert.Contains("\"command\":\"threads\"", response);
-                Assert.Contains("\"name\":\"Job: ci-job\"", response);
-                await _debugger.StopAsync();
+                    var response = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
+                    Assert.Contains("\"command\":\"threads\"", response);
+                    Assert.Contains("\"name\":\"Job: ci-job\"", response);
+                    await _debugger.StopAsync();
+                });
             }
         }
 
@@ -356,27 +354,30 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-
-                var waitTask = _debugger.WaitUntilReadyAsync();
-                using var client = await ConnectClientAsync(port);
-                await SendRequestAsync(client.GetStream(), new Request
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
                 {
-                    Seq = 1,
-                    Type = "request",
-                    Command = "configurationDone"
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
+
+                    var waitTask = _debugger.WaitUntilReadyAsync();
+                    using var client = await ConnectClientAsync(port);
+                    await SendRequestAsync(client.GetStream(), new Request
+                    {
+                        Seq = 1,
+                        Type = "request",
+                        Command = "configurationDone"
+                    });
+
+                    await waitTask;
+                    cts.Cancel();
+
+                    // In the real runner, JobRunner always calls OnJobCompletedAsync
+                    // from a finally block. The cancellation callback only unblocks
+                    // pending waits; OnJobCompletedAsync handles state + cleanup.
+                    await _debugger.OnJobCompletedAsync();
+                    Assert.Equal(DapSessionState.Terminated, _debugger.State);
                 });
-
-                await waitTask;
-                cts.Cancel();
-
-                // In the real runner, JobRunner always calls OnJobCompletedAsync
-                // from a finally block. The cancellation callback only unblocks
-                // pending waits; OnJobCompletedAsync handles state + cleanup.
-                await _debugger.OnJobCompletedAsync();
-                Assert.Equal(DapSessionState.Terminated, _debugger.State);
             }
         }
 
@@ -399,22 +400,25 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-
-                var waitTask = _debugger.WaitUntilReadyAsync();
-                using var client = await ConnectClientAsync(port);
-                await SendRequestAsync(client.GetStream(), new Request
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
                 {
-                    Seq = 1,
-                    Type = "request",
-                    Command = "configurationDone"
-                });
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
 
-                await waitTask;
-                await _debugger.OnJobCompletedAsync();
-                Assert.Equal(DapSessionState.Terminated, _debugger.State);
+                    var waitTask = _debugger.WaitUntilReadyAsync();
+                    using var client = await ConnectClientAsync(port);
+                    await SendRequestAsync(client.GetStream(), new Request
+                    {
+                        Seq = 1,
+                        Type = "request",
+                        Command = "configurationDone"
+                    });
+
+                    await waitTask;
+                    await _debugger.OnJobCompletedAsync();
+                    Assert.Equal(DapSessionState.Terminated, _debugger.State);
+                });
             }
         }
 
@@ -437,17 +441,20 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
+                {
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
 
-                var waitTask = _debugger.WaitUntilReadyAsync();
-                await Task.Delay(50);
-                cts.Cancel();
+                    var waitTask = _debugger.WaitUntilReadyAsync();
+                    await Task.Delay(50);
+                    cts.Cancel();
 
-                var ex = await Assert.ThrowsAnyAsync<OperationCanceledException>(() => waitTask);
-                Assert.IsNotType<TimeoutException>(ex);
-                await _debugger.StopAsync();
+                    var ex = await Assert.ThrowsAnyAsync<OperationCanceledException>(() => waitTask);
+                    Assert.IsNotType<TimeoutException>(ex);
+                    await _debugger.StopAsync();
+                });
             }
         }
 
@@ -464,29 +471,32 @@ namespace GitHub.Runner.Common.Tests.Worker
                 hc.SecretMasker.AddValue("initialized");
 
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-                using var client = await ConnectClientAsync(port);
-                var stream = client.GetStream();
-
-                await SendRequestAsync(stream, new Request
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
                 {
-                    Seq = 1,
-                    Type = "request",
-                    Command = "initialize"
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
+                    using var client = await ConnectClientAsync(port);
+                    var stream = client.GetStream();
+
+                    await SendRequestAsync(stream, new Request
+                    {
+                        Seq = 1,
+                        Type = "request",
+                        Command = "initialize"
+                    });
+
+                    var response = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
+                    Assert.Contains("\"type\":\"response\"", response);
+                    Assert.Contains("\"command\":\"initialize\"", response);
+                    Assert.Contains("\"success\":true", response);
+
+                    var initializedEvent = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
+                    Assert.Contains("\"type\":\"event\"", initializedEvent);
+                    Assert.Contains("\"event\":\"initialized\"", initializedEvent);
+
+                    await _debugger.StopAsync();
                 });
-
-                var response = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
-                Assert.Contains("\"type\":\"response\"", response);
-                Assert.Contains("\"command\":\"initialize\"", response);
-                Assert.Contains("\"success\":true", response);
-
-                var initializedEvent = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
-                Assert.Contains("\"type\":\"event\"", initializedEvent);
-                Assert.Contains("\"event\":\"initialized\"", initializedEvent);
-
-                await _debugger.StopAsync();
             }
         }
 
@@ -498,38 +508,41 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-
-                // Complete handshake so session is ready
-                var waitTask = _debugger.WaitUntilReadyAsync();
-                using var client = await ConnectClientAsync(port);
-                var stream = client.GetStream();
-                await SendRequestAsync(stream, new Request
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
                 {
-                    Seq = 1,
-                    Type = "request",
-                    Command = "configurationDone"
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
+
+                    // Complete handshake so session is ready
+                    var waitTask = _debugger.WaitUntilReadyAsync();
+                    using var client = await ConnectClientAsync(port);
+                    var stream = client.GetStream();
+                    await SendRequestAsync(stream, new Request
+                    {
+                        Seq = 1,
+                        Type = "request",
+                        Command = "configurationDone"
+                    });
+                    await waitTask;
+
+                    // Simulate a step starting (which pauses)
+                    var step = new Mock<IStep>();
+                    step.Setup(s => s.DisplayName).Returns("Test Step");
+                    step.Setup(s => s.ExecutionContext).Returns((IExecutionContext)null);
+                    var stepTask = _debugger.OnStepStartingAsync(step.Object);
+
+                    // Give the step time to pause
+                    await Task.Delay(50);
+
+                    // Cancel the job — should release the step pause
+                    cts.Cancel();
+                    await stepTask;
+
+                    // In the real runner, OnJobCompletedAsync always follows.
+                    await _debugger.OnJobCompletedAsync();
+                    Assert.Equal(DapSessionState.Terminated, _debugger.State);
                 });
-                await waitTask;
-
-                // Simulate a step starting (which pauses)
-                var step = new Mock<IStep>();
-                step.Setup(s => s.DisplayName).Returns("Test Step");
-                step.Setup(s => s.ExecutionContext).Returns((IExecutionContext)null);
-                var stepTask = _debugger.OnStepStartingAsync(step.Object);
-
-                // Give the step time to pause
-                await Task.Delay(50);
-
-                // Cancel the job — should release the step pause
-                cts.Cancel();
-                await stepTask;
-
-                // In the real runner, OnJobCompletedAsync always follows.
-                await _debugger.OnJobCompletedAsync();
-                Assert.Equal(DapSessionState.Terminated, _debugger.State);
             }
         }
 
@@ -545,10 +558,13 @@ namespace GitHub.Runner.Common.Tests.Worker
 
                 // Start then immediate stop (no connection, no WaitUntilReady)
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-                await _debugger.StopAsync();
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
+                {
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
+                    await _debugger.StopAsync();
+                });
 
                 // StopAsync after already stopped
                 await _debugger.StopAsync();
@@ -563,34 +579,37 @@ namespace GitHub.Runner.Common.Tests.Worker
             using (CreateTestContext())
             {
                 var port = GetFreePort();
-                using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-                var jobContext = CreateJobContextWithTunnel(cts.Token, port);
-                await _debugger.StartAsync(jobContext.Object);
-
-                var waitTask = _debugger.WaitUntilReadyAsync();
-                using var client = await ConnectClientAsync(port);
-                var stream = client.GetStream();
-                await SendRequestAsync(stream, new Request
+                await WithEnvironmentVariableAsync(PortEnvironmentVariable, port.ToString(), async () =>
                 {
-                    Seq = 1,
-                    Type = "request",
-                    Command = "configurationDone"
+                    using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+                    var jobContext = CreateJobContext(cts.Token);
+                    await _debugger.StartAsync(jobContext.Object);
+
+                    var waitTask = _debugger.WaitUntilReadyAsync();
+                    using var client = await ConnectClientAsync(port);
+                    var stream = client.GetStream();
+                    await SendRequestAsync(stream, new Request
+                    {
+                        Seq = 1,
+                        Type = "request",
+                        Command = "configurationDone"
+                    });
+
+                    // Read the configurationDone response
+                    await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
+                    await waitTask;
+
+                    // Complete the job — events are sent via OnJobCompletedAsync
+                    await _debugger.OnJobCompletedAsync();
+
+                    var msg1 = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
+                    var msg2 = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
+
+                    // Both events should arrive (order may vary)
+                    var combined = msg1 + msg2;
+                    Assert.Contains("\"event\":\"terminated\"", combined);
+                    Assert.Contains("\"event\":\"exited\"", combined);
                 });
-
-                // Read the configurationDone response
-                await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
-                await waitTask;
-
-                // Complete the job — events are sent via OnJobCompletedAsync
-                await _debugger.OnJobCompletedAsync();
-
-                var msg1 = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
-                var msg2 = await ReadDapMessageAsync(stream, TimeSpan.FromSeconds(5));
-
-                // Both events should arrive (order may vary)
-                var combined = msg1 + msg2;
-                Assert.Contains("\"event\":\"terminated\"", combined);
-                Assert.Contains("\"event\":\"exited\"", combined);
             }
         }
     }