Node 24 enforcement + Linux ARM32 deprecation support

src/Runner.Common/Constants.cs

@@ -195,8 +195,22 @@ public static class NodeMigration
                 public static readonly string RequireNode24Flag = "actions.runner.requirenode24";
                 public static readonly string WarnOnNode20Flag = "actions.runner.warnonnode20";
 
+                // Feature flags for Linux ARM32 deprecation
+                public static readonly string DeprecateLinuxArm32Flag = "actions_runner_deprecate_linux_arm32";
+                public static readonly string KillLinuxArm32Flag = "actions_runner_kill_linux_arm32";
+
                 // Blog post URL for Node 20 deprecation
                 public static readonly string Node20DeprecationUrl = "https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/";
+
+                // Node 20 migration dates (hardcoded fallbacks, can be overridden via job variables)
+                public static readonly string Node24DefaultDate = "June 2nd, 2026";
+                public static readonly string Node20RemovalDate = "September 16th, 2026";
+
+                // Variable keys for server-overridable dates
+                public static readonly string Node24DefaultDateVariable = "actions_runner_node24_default_date";
+                public static readonly string Node20RemovalDateVariable = "actions_runner_node20_removal_date";
+
+                public static readonly string LinuxArm32DeprecationMessage = "Linux ARM32 runners are deprecated and will no longer be supported after {0}. Please migrate to a supported platform.";
             }
 
             public static readonly string InternalTelemetryIssueDataKey = "_internal_telemetry";

src/Runner.Common/Util/NodeUtil.cs

@@ -58,7 +58,7 @@ public static (string nodeVersion, string warningMessage) DetermineActionsNodeVe
             {
                 return (Constants.Runner.NodeMigration.Node24, null);
             }
-            
+
             // Get environment variable details with source information
             var forceNode24Details = GetEnvironmentVariableDetails(
                 Constants.Runner.NodeMigration.ForceNode24Variable, workflowEnvironment);
@@ -108,14 +108,50 @@ public static (string nodeVersion, string warningMessage) DetermineActionsNodeVe
 
         /// <summary>
         /// Checks if Node24 is requested but running on ARM32 Linux, and determines if fallback is needed.
+        /// Also handles ARM32 deprecation and kill switch phases.
         /// </summary>
         /// <param name="preferredVersion">The preferred Node version</param>
+        /// <param name="deprecateArm32">Feature flag indicating ARM32 Linux is deprecated</param>
+        /// <param name="killArm32">Feature flag indicating ARM32 Linux should no longer work</param>
         /// <returns>A tuple containing the adjusted node version and an optional warning message</returns>
-        public static (string nodeVersion, string warningMessage) CheckNodeVersionForLinuxArm32(string preferredVersion)
+        public static (string nodeVersion, string warningMessage) CheckNodeVersionForLinuxArm32(
+            string preferredVersion,
+            bool deprecateArm32 = false,
+            bool killArm32 = false,
+            string node20RemovalDate = null)
         {
-            if (string.Equals(preferredVersion, Constants.Runner.NodeMigration.Node24, StringComparison.OrdinalIgnoreCase) &&
-                Constants.Runner.PlatformArchitecture.Equals(Constants.Architecture.Arm) &&
-                Constants.Runner.Platform.Equals(Constants.OSPlatform.Linux))
+            bool isArm32Linux = Constants.Runner.PlatformArchitecture.Equals(Constants.Architecture.Arm) &&
+                                Constants.Runner.Platform.Equals(Constants.OSPlatform.Linux);
+
+            if (!isArm32Linux)
+            {
+                return (preferredVersion, null);
+            }
+
+            // ARM32 kill switch: runner should no longer work on this platform
+            if (killArm32)
+            {
+                return (null, "Linux ARM32 runners are no longer supported. Please migrate to a supported platform.");
+            }
+
+            // ARM32 deprecation warning: continue using node20 but warn about upcoming end of support
+            if (deprecateArm32)
+            {
+                string effectiveDate = string.IsNullOrEmpty(node20RemovalDate) ? Constants.Runner.NodeMigration.Node20RemovalDate : node20RemovalDate;
+                string deprecationWarning = string.Format(
+                    Constants.Runner.NodeMigration.LinuxArm32DeprecationMessage,
+                    effectiveDate);
+
+                if (string.Equals(preferredVersion, Constants.Runner.NodeMigration.Node24, StringComparison.OrdinalIgnoreCase))
+                {
+                    return (Constants.Runner.NodeMigration.Node20, deprecationWarning);
+                }
+
+                return (preferredVersion, deprecationWarning);
+            }
+
+            // Legacy behavior: fall back to node20 if node24 was requested on ARM32
+            if (string.Equals(preferredVersion, Constants.Runner.NodeMigration.Node24, StringComparison.OrdinalIgnoreCase))
             {
                 return (Constants.Runner.NodeMigration.Node20, "Node 24 is not supported on Linux ARM32 platforms. Falling back to Node 20.");
             }

src/Runner.Worker/ExecutionContext.cs

@@ -854,6 +854,12 @@ public void InitializeJob(Pipelines.AgentJobRequestMessage message, Cancellation
             // Track Node.js 20 actions for deprecation warning
             Global.DeprecatedNode20Actions = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
 
+            // Track actions upgraded from Node.js 20 to Node.js 24
+            Global.UpgradedToNode24Actions = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+            // Track actions stuck on Node.js 20 due to ARM32 (separate from general deprecation)
+            Global.Arm32Node20Actions = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
             // Job Outputs
             JobOutputs = new Dictionary<string, VariableValue>(StringComparer.OrdinalIgnoreCase);
 

src/Runner.Worker/GlobalContext.cs

@@ -34,5 +34,7 @@ public sealed class GlobalContext
         public bool HasDeprecatedSetOutput { get; set; }
         public bool HasDeprecatedSaveState { get; set; }
         public HashSet<string> DeprecatedNode20Actions { get; set; }
+        public HashSet<string> UpgradedToNode24Actions { get; set; }
+        public HashSet<string> Arm32Node20Actions { get; set; }
     }
 }

src/Runner.Worker/Handlers/HandlerFactory.cs

@@ -25,6 +25,14 @@ IHandler Create(
 
     public sealed class HandlerFactory : RunnerService, IHandlerFactory
     {
+        internal static bool ShouldTrackAsArm32Node20(bool deprecateArm32, string preferredNodeVersion, string finalNodeVersion, string platformWarningMessage)
+        {
+            return deprecateArm32 &&
+                !string.IsNullOrEmpty(platformWarningMessage) &&
+                string.Equals(preferredNodeVersion, Constants.Runner.NodeMigration.Node24, StringComparison.OrdinalIgnoreCase) &&
+                string.Equals(finalNodeVersion, Constants.Runner.NodeMigration.Node20, StringComparison.OrdinalIgnoreCase);
+        }
+
         public IHandler Create(
             IExecutionContext executionContext,
             Pipelines.ActionStepDefinitionReference action,
@@ -65,19 +73,12 @@ public IHandler Create(
                     nodeData.NodeVersion = Common.Constants.Runner.NodeMigration.Node20;
                 }
 
-                // Track Node.js 20 actions for deprecation annotation
-                if (string.Equals(nodeData.NodeVersion, Constants.Runner.NodeMigration.Node20, StringComparison.InvariantCultureIgnoreCase))
-                {
-                    bool warnOnNode20 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.WarnOnNode20Flag) ?? false;
-                    if (warnOnNode20)
-                    {
-                        string actionName = GetActionName(action);
-                        if (!string.IsNullOrEmpty(actionName))
-                        {
-                            executionContext.Global.DeprecatedNode20Actions?.Add(actionName);
-                        }
-                    }
-                }
+                // Read flags early; actionName is also resolved up front for tracking after version is determined
+                bool warnOnNode20 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.WarnOnNode20Flag) ?? false;
+                bool deprecateArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.DeprecateLinuxArm32Flag) ?? false;
+                bool killArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.KillLinuxArm32Flag) ?? false;
+                string node20RemovalDate = executionContext.Global.Variables?.Get(Constants.Runner.NodeMigration.Node20RemovalDateVariable);
+                string actionName = GetActionName(action);
 
                 // Check if node20 was explicitly specified in the action
                 // We don't modify if node24 was explicitly specified
@@ -87,7 +88,15 @@ public IHandler Create(
                     bool requireNode24 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.RequireNode24Flag) ?? false;
 
                     var (nodeVersion, configWarningMessage) = NodeUtil.DetermineActionsNodeVersion(environment, useNode24ByDefault, requireNode24);
-                    var (finalNodeVersion, platformWarningMessage) = NodeUtil.CheckNodeVersionForLinuxArm32(nodeVersion);
+                    var (finalNodeVersion, platformWarningMessage) = NodeUtil.CheckNodeVersionForLinuxArm32(nodeVersion, deprecateArm32, killArm32, node20RemovalDate);
+
+                    // ARM32 kill switch: fail the step
+                    if (finalNodeVersion == null)
+                    {
+                        executionContext.Error(platformWarningMessage);
+                        throw new InvalidOperationException(platformWarningMessage);
+                    }
+
                     nodeData.NodeVersion = finalNodeVersion;
 
                     if (!string.IsNullOrEmpty(configWarningMessage))
@@ -100,6 +109,26 @@ public IHandler Create(
                         executionContext.Warning(platformWarningMessage);
                     }
 
+                    // Track actions based on their final node version
+                    if (!string.IsNullOrEmpty(actionName))
+                    {
+                        if (string.Equals(finalNodeVersion, Constants.Runner.NodeMigration.Node24, StringComparison.OrdinalIgnoreCase))
+                        {
+                            // Action was upgraded from node20 to node24
+                            executionContext.Global.UpgradedToNode24Actions?.Add(actionName);
+                        }
+                        else if (ShouldTrackAsArm32Node20(deprecateArm32, nodeVersion, finalNodeVersion, platformWarningMessage))
+                        {
+                            // Action is on node20 because ARM32 can't run node24
+                            executionContext.Global.Arm32Node20Actions?.Add(actionName);
+                        }
+                        else if (warnOnNode20)
+                        {
+                            // Action is still running on node20 (general case)
+                            executionContext.Global.DeprecatedNode20Actions?.Add(actionName);
+                        }
+                    }
+
                     // Show information about Node 24 migration in Phase 2
                     if (useNode24ByDefault && !requireNode24 && string.Equals(finalNodeVersion, Constants.Runner.NodeMigration.Node24, StringComparison.OrdinalIgnoreCase))
                     {
@@ -109,6 +138,30 @@ public IHandler Create(
                         executionContext.Output(infoMessage);
                     }
                 }
+                else if (string.Equals(nodeData.NodeVersion, Constants.Runner.NodeMigration.Node24, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    var (finalNodeVersion, platformWarningMessage) = NodeUtil.CheckNodeVersionForLinuxArm32(nodeData.NodeVersion, deprecateArm32, killArm32, node20RemovalDate);
+
+                    // ARM32 kill switch: fail the step
+                    if (finalNodeVersion == null)
+                    {
+                        executionContext.Error(platformWarningMessage);
+                        throw new InvalidOperationException(platformWarningMessage);
+                    }
+
+                    var preferredVersion = nodeData.NodeVersion;
+                    nodeData.NodeVersion = finalNodeVersion;
+
+                    if (!string.IsNullOrEmpty(platformWarningMessage))
+                    {
+                        executionContext.Warning(platformWarningMessage);
+                    }
+
+                    if (!string.IsNullOrEmpty(actionName) && ShouldTrackAsArm32Node20(deprecateArm32, preferredVersion, finalNodeVersion, platformWarningMessage))
+                    {
+                        executionContext.Global.Arm32Node20Actions?.Add(actionName);
+                    }
+                }
 
                 (handler as INodeScriptActionHandler).Data = nodeData;
             }

src/Runner.Worker/Handlers/StepHost.cs

@@ -58,13 +58,23 @@ public string ResolvePathForStepHost(IExecutionContext executionContext, string
 
         public Task<string> DetermineNodeRuntimeVersion(IExecutionContext executionContext, string preferredVersion)
         {
-            // Use NodeUtil to check if Node24 is requested but we're on ARM32 Linux
-            var (nodeVersion, warningMessage) = Common.Util.NodeUtil.CheckNodeVersionForLinuxArm32(preferredVersion);
+            bool deprecateArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.DeprecateLinuxArm32Flag) ?? false;
+            bool killArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.KillLinuxArm32Flag) ?? false;
+            string node20RemovalDate = executionContext.Global.Variables?.Get(Constants.Runner.NodeMigration.Node20RemovalDateVariable);
+
+            var (nodeVersion, warningMessage) = Common.Util.NodeUtil.CheckNodeVersionForLinuxArm32(preferredVersion, deprecateArm32, killArm32, node20RemovalDate);
+
+            if (nodeVersion == null)
+            {
+                executionContext.Error(warningMessage);
+                throw new InvalidOperationException(warningMessage);
+            }
+
             if (!string.IsNullOrEmpty(warningMessage))
             {
                 executionContext.Warning(warningMessage);
             }
-            
+
             return Task.FromResult(nodeVersion);
         }
 
@@ -142,8 +152,18 @@ public string ResolvePathForStepHost(IExecutionContext executionContext, string
 
         public async Task<string> DetermineNodeRuntimeVersion(IExecutionContext executionContext, string preferredVersion)
         {
-            // Use NodeUtil to check if Node24 is requested but we're on ARM32 Linux
-            var (nodeExternal, warningMessage) = Common.Util.NodeUtil.CheckNodeVersionForLinuxArm32(preferredVersion);
+            bool deprecateArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.DeprecateLinuxArm32Flag) ?? false;
+            bool killArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.KillLinuxArm32Flag) ?? false;
+            string node20RemovalDate = executionContext.Global.Variables?.Get(Constants.Runner.NodeMigration.Node20RemovalDateVariable);
+
+            var (nodeExternal, warningMessage) = Common.Util.NodeUtil.CheckNodeVersionForLinuxArm32(preferredVersion, deprecateArm32, killArm32, node20RemovalDate);
+
+            if (nodeExternal == null)
+            {
+                executionContext.Error(warningMessage);
+                throw new InvalidOperationException(warningMessage);
+            }
+
             if (!string.IsNullOrEmpty(warningMessage))
             {
                 executionContext.Warning(warningMessage);
@@ -273,8 +293,18 @@ await containerHookManager.RunScriptStepAsync(context,
 
         private string CheckPlatformForAlpineContainer(IExecutionContext executionContext, string preferredVersion)
         {
-            // Use NodeUtil to check if Node24 is requested but we're on ARM32 Linux
-            var (nodeExternal, warningMessage) = Common.Util.NodeUtil.CheckNodeVersionForLinuxArm32(preferredVersion);
+            bool deprecateArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.DeprecateLinuxArm32Flag) ?? false;
+            bool killArm32 = executionContext.Global.Variables?.GetBoolean(Constants.Runner.NodeMigration.KillLinuxArm32Flag) ?? false;
+            string node20RemovalDate = executionContext.Global.Variables?.Get(Constants.Runner.NodeMigration.Node20RemovalDateVariable);
+
+            var (nodeExternal, warningMessage) = Common.Util.NodeUtil.CheckNodeVersionForLinuxArm32(preferredVersion, deprecateArm32, killArm32, node20RemovalDate);
+
+            if (nodeExternal == null)
+            {
+                executionContext.Error(warningMessage);
+                throw new InvalidOperationException(warningMessage);
+            }
+
             if (!string.IsNullOrEmpty(warningMessage))
             {
                 executionContext.Warning(warningMessage);