Enable nullable in Stack, Libraries (9), and Applications projects

Applications/ConsoleReferenceClient/ClientSamples.cs

@@ -67,8 +67,8 @@ public class ClientSamples
 
         public ClientSamples(
             ITelemetryContext telemetry,
-            Action<IList, IList> validateResponse,
-            ManualResetEvent quitEvent = null,
+            Action<IList, IList>? validateResponse,
+            ManualResetEvent? quitEvent = null,
             bool verbose = false)
         {
             m_telemetry = telemetry;
@@ -587,9 +587,16 @@ public async Task<IList<INode>> FetchAllNodesNodeCacheAsync(
             // add root node
             if (addRootNode)
             {
-                INode rootNode = await uaClient.Session.NodeCache.FindAsync(startingNode, ct)
+                INode? rootNode = await uaClient.Session.NodeCache.FindAsync(startingNode, ct)
                     .ConfigureAwait(false);
-                nodeDictionary[rootNode.NodeId] = rootNode;
+                if (rootNode == null)
+                {
+                    m_logger.LogWarning("Root node {NodeId} not found, skipping", startingNode);
+                }
+                else
+                {
+                    nodeDictionary[rootNode.NodeId] = rootNode;
+                }
             }
 
             int searchDepth = 0;
@@ -625,7 +632,7 @@ public async Task<IList<INode>> FetchAllNodesNodeCacheAsync(
                             // no need to browse property types
                             if (node is VariableNode variableNode)
                             {
-                                IReference hasTypeDefinition = variableNode.ReferenceTable
+                                IReference? hasTypeDefinition = variableNode.ReferenceTable
                                     .FirstOrDefault(r =>
                                         r.ReferenceTypeId
                                             .Equals(ReferenceTypeIds.HasTypeDefinition));
@@ -712,7 +719,7 @@ public async Task<IList<INode>> FetchAllNodesNodeCacheAsync(
         public async Task<ArrayOf<ReferenceDescription>> ManagedBrowseFullAddressSpaceAsync(
             IUAClient uaClient,
             NodeId startingNode = default,
-            BrowseDescription browseDescription = null,
+            BrowseDescription? browseDescription = null,
             CancellationToken ct = default)
         {
             ContinuationPointPolicy policyBackup = uaClient.Session.ContinuationPointPolicy;
@@ -888,7 +895,7 @@ await uaClient
         public async Task<ArrayOf<ReferenceDescription>> BrowseFullAddressSpaceAsync(
             IUAClient uaClient,
             NodeId startingNode = default,
-            BrowseDescription browseDescription = null,
+            BrowseDescription? browseDescription = null,
             CancellationToken ct = default)
         {
             var stopWatch = new Stopwatch();
@@ -1176,8 +1183,8 @@ public async Task<ResultSet<DataValue>> ReadAllValuesAsync(
             CancellationToken ct = default)
         {
             bool retrySingleRead = false;
-            List<DataValue> values = null;
-            List<ServiceResult> errors = null;
+            List<DataValue>? values = null;
+            List<ServiceResult>? errors = null;
 
             do
             {
@@ -1259,7 +1266,7 @@ public async Task<ResultSet<DataValue>> ReadAllValuesAsync(
                 }
             } while (retrySingleRead);
 
-            return ResultSet.From(values, errors);
+            return ResultSet.From(values!, errors!);
         }
 
         /// <summary>
@@ -1361,7 +1368,7 @@ public static string FormatValueAsJson(
             IServiceMessageContext messageContext,
             string name,
             DataValue value,
-            JsonEncoderOptions jsonEncodingType = null)
+            JsonEncoderOptions? jsonEncodingType = null)
         {
             string textbuffer;
             using (var jsonEncoder = new JsonEncoder(messageContext, jsonEncodingType))
@@ -1436,7 +1443,13 @@ private void OnMonitoredItemNotification(
             try
             {
                 // Log MonitoredItem Notification event
-                var notification = e.NotificationValue as MonitoredItemNotification;
+                if (e.NotificationValue is not MonitoredItemNotification notification)
+                {
+                    m_logger.LogWarning(
+                        "Unexpected notification type: {Type}",
+                        e.NotificationValue?.GetType().Name ?? "null");
+                    return;
+                }
                 DateTime localTime = notification.Value.SourceTimestamp.ToLocalTime();
                 m_logger.LogInformation(
                     "Notification: {SequenceNumber} \"{NodeId}\" and Value = {Value} at [{CurrentTime}].",
@@ -1461,7 +1474,13 @@ private void OnMonitoredItemEventNotification(
             try
             {
                 // Log MonitoredItem Notification event
-                var notification = e.NotificationValue as EventFieldList;
+                if (e.NotificationValue is not EventFieldList notification)
+                {
+                    m_logger.LogWarning(
+                        "Unexpected event notification type: {Type}",
+                        e.NotificationValue?.GetType().Name ?? "null");
+                    return;
+                }
 
                 foreach (KeyValuePair<int, ArrayOf<QualifiedName>> entry in m_desiredEventFields)
                 {
@@ -1559,7 +1578,7 @@ private static ArrayOf<BrowseDescription> CreateBrowseDescriptionCollectionFromN
             var browseDescriptionCollection = new List<BrowseDescription>();
             foreach (NodeId nodeId in nodeIdCollection)
             {
-                BrowseDescription browseDescription = CoreUtils.Clone(template);
+                BrowseDescription browseDescription = CoreUtils.Clone(template)!;
                 browseDescription.NodeId = nodeId;
                 browseDescriptionCollection.Add(browseDescription);
             }
@@ -1621,7 +1640,7 @@ public async Task<IReadOnlyDictionary<string, string>> ExportNodesToNodeSet2PerN
             ISession session,
             IList<INode> nodes,
             string outputDirectory,
-            IReadOnlyCollection<string> targetNamespaces = null,
+            IReadOnlyCollection<string>? targetNamespaces = null,
             CancellationToken cancellationToken = default)
         {
             if (session == null)
@@ -1637,7 +1656,7 @@ public async Task<IReadOnlyDictionary<string, string>> ExportNodesToNodeSet2PerN
                 throw new ArgumentException("Value cannot be null or whitespace.", nameof(outputDirectory));
             }
 
-            HashSet<string> targetSet = targetNamespaces is { Count: > 0 }
+            HashSet<string>? targetSet = targetNamespaces is { Count: > 0 }
                 ? new HashSet<string>(targetNamespaces, StringComparer.OrdinalIgnoreCase)
                 : null;
 
@@ -1658,16 +1677,17 @@ public async Task<IReadOnlyDictionary<string, string>> ExportNodesToNodeSet2PerN
                 .GroupBy(node => node.NodeId.NamespaceIndex)
                 .Where(group =>
                 {
-                    string namespaceUri = session.NamespaceUris.GetString(group.Key);
+                    string? namespaceUri = session.NamespaceUris.GetString(group.Key);
                     if (string.IsNullOrEmpty(namespaceUri))
                     {
                         return false;
                     }
 
                     if (targetSet != null)
                     {
-                        // Caller asked for a specific set of namespaces.
-                        return targetSet.Contains(namespaceUri);
+                        // Caller asked for a specific set of namespaces. namespaceUri is non-null
+                        // after !IsNullOrEmpty (NotNullWhen attribute not available on net48).
+                        return targetSet.Contains(namespaceUri!);
                     }
 
                     // Default: exclude only the OPC UA base namespace; include companion specs.
@@ -1684,7 +1704,8 @@ public async Task<IReadOnlyDictionary<string, string>> ExportNodesToNodeSet2PerN
             {
                 cancellationToken.ThrowIfCancellationRequested();
 
-                string namespaceUri = session.NamespaceUris.GetString(kvp.Key);
+                // The Where clause above filtered out null/empty namespace URIs.
+                string namespaceUri = session.NamespaceUris.GetString(kvp.Key)!;
 
                 // Create a safe filename from the namespace URI
 
@@ -1786,18 +1807,18 @@ private void ValidateResponse<TRequest, TResponse>(
         {
             if (m_validate != null)
             {
-                m_validate(requests.ToArray(), responses.ToArray());
+                m_validate(requests.ToArray()!, responses.ToArray()!);
             }
             else
             {
                 ClientBase.ValidateResponse(responses, requests);
             }
         }
 
-        private readonly Action<IList, IList> m_validate;
+        private readonly Action<IList, IList>? m_validate;
         private readonly ITelemetryContext m_telemetry;
         private readonly ILogger m_logger;
-        private readonly ManualResetEvent m_quitEvent;
+        private readonly ManualResetEvent? m_quitEvent;
         private readonly bool m_verbose;
         private readonly Dictionary<int, ArrayOf<QualifiedName>> m_desiredEventFields;
         private int m_processedEvents;

Applications/ConsoleReferenceClient/ConnectTester.cs

@@ -50,7 +50,7 @@ public sealed class ConnectTester : IDisposable
     {
         public ConnectTester(
             ITelemetryContext telemetry,
-            ManualResetEvent quitEvent = null)
+            ManualResetEvent? quitEvent = null)
         {
             m_quitEvent = quitEvent;
             m_telemetry = telemetry;
@@ -100,7 +100,7 @@ public async Task RunAsync(CancellationToken ct)
                     .LoadApplicationConfigurationAsync(silent: false, ct: ct)
                     .ConfigureAwait(false);
 
-                m_configuration.CertificateValidator.CertificateValidation += CertificateValidation;
+                m_configuration.CertificateValidator!.CertificateValidation += CertificateValidation;
 
                 // check the application certificate.
                 bool haveAppCertificate = await application
@@ -123,16 +123,17 @@ public async Task RunAsync(CancellationToken ct)
                 var sessionFactory = new DefaultSessionFactory(m_telemetry);
                 var userNameidentity = new UserIdentity(kUserName, new UTF8Encoding(false).GetBytes(kPassword));
 
-                foreach (EndpointDescription ii in endpoints.ToArray())
+                foreach (EndpointDescription ii in endpoints.ToArray()!)
                 {
-                    string userCertificateFile = GetUserCertificateFile(ii.SecurityPolicyUri);
+                    string securityPolicyUri = ii.SecurityPolicyUri!;
+                    string userCertificateFile = GetUserCertificateFile(securityPolicyUri);
 
                     X509Certificate2 x509 = X509CertificateLoader.LoadPkcs12FromFile(
                         Path.Combine("..\\..\\pki\\trustedUser\\private",
                         userCertificateFile),
                         "password");
 
-                    string thumbprint = x509.Thumbprint;
+                    string thumbprint = x509.Thumbprint!;
 
                     UserIdentity certificateIdentity = await LoadUserCertificateAsync(thumbprint, "password", ct).ConfigureAwait(false);
 
@@ -158,7 +159,7 @@ public async Task RunAsync(CancellationToken ct)
 
                             m_logger.LogWarning(
                                 "SECURITY-POLICY={SecurityPolicyUri} {SecurityMode}",
-                                SecurityPolicies.GetDisplayName(ii.SecurityPolicyUri),
+                                SecurityPolicies.GetDisplayName(securityPolicyUri),
                                 ii.SecurityMode);
 
                             m_logger.LogWarning(
@@ -209,7 +210,7 @@ public async Task RunAsync(CancellationToken ct)
 
                             m_logger.LogWarning(
                                 "SECURITY-POLICY={SecurityPolicyUri} {SecurityMode}",
-                                SecurityPolicies.GetDisplayName(ii.SecurityPolicyUri),
+                                SecurityPolicies.GetDisplayName(securityPolicyUri),
                                 ii.SecurityMode);
 
                             m_logger.LogWarning(
@@ -222,15 +223,15 @@ public async Task RunAsync(CancellationToken ct)
 
                         m_logger.LogWarning(
                             "TEST COMPLETE: {SecurityPolicyUri} {SecurityMode}",
-                            SecurityPolicies.GetDisplayName(ii.SecurityPolicyUri),
+                            SecurityPolicies.GetDisplayName(securityPolicyUri),
                             ii.SecurityMode);
 
                         m_logger.LogWarning("{Line}", new string('=', 80));
                     }
                 }
 
                 Console.WriteLine("Ctrl-C to stop.");
-                m_quitEvent.WaitOne();
+                m_quitEvent!.WaitOne();
             }
             catch (Exception e)
             {
@@ -258,7 +259,7 @@ internal async Task<SessionWrapper> RunTestAsync(
                     endpoint,
                     false,
                     false,
-                    m_configuration.ApplicationName,
+                    m_configuration.ApplicationName!,
                     600000,
                     //new UserIdentity(),
                     endpointDescription.SecurityMode != MessageSecurityMode.None ? identity : new UserIdentity(),
@@ -293,14 +294,14 @@ private async Task<UserIdentity> LoadUserCertificateAsync(
             string password,
             CancellationToken ct)
         {
-            CertificateTrustList store = m_configuration.SecurityConfiguration.TrustedUserCertificates;
+            CertificateTrustList store = m_configuration.SecurityConfiguration.TrustedUserCertificates!;
 #if NET8_0_OR_GREATER
             // get user certificate with matching thumbprint
             X509Certificate2Collection certificates =
                 await store.GetCertificatesAsync(m_telemetry, ct).ConfigureAwait(false);
             X509Certificate2 hit = certificates
                 .Find(X509FindType.FindByThumbprint, thumbprint, false)
-                .FirstOrDefault();
+                .FirstOrDefault()!;
 
             // create Certificate Identifier
             var cid = new CertificateIdentifier(hit)
@@ -386,7 +387,7 @@ private void Session_KeepAlive(ISession session, KeepAliveEventArgs e)
                 // start reconnect sequence on communication error.
                 if (ServiceResult.IsBad(e.Status))
                 {
-                    SessionReconnectHandler.ReconnectState state = m_reconnectHandler
+                    SessionReconnectHandler.ReconnectState state = m_reconnectHandler!
                         .BeginReconnect(
                             m_wrapper.Session,
                             null,
@@ -420,7 +421,7 @@ private void Session_KeepAlive(ISession session, KeepAliveEventArgs e)
             }
         }
 
-        private void Client_ReconnectComplete(object sender, EventArgs e)
+        private void Client_ReconnectComplete(object? sender, EventArgs e)
         {
             // ignore callbacks from discarded objects.
             if (!ReferenceEquals(sender, m_reconnectHandler))
@@ -431,11 +432,11 @@ private void Client_ReconnectComplete(object sender, EventArgs e)
             lock (m_lock)
             {
                 // if session recovered, Session property is null
-                if (m_reconnectHandler.Session != null)
+                if (m_reconnectHandler!.Session != null)
                 {
                     // ensure only a new instance is disposed
                     // after reactivate, the same session instance may be returned
-                    if (!ReferenceEquals(m_wrapper.Session, m_reconnectHandler.Session))
+                    if (!ReferenceEquals(m_wrapper!.Session, m_reconnectHandler.Session))
                     {
                         m_logger.LogInformation(
                             "--- RECONNECTED TO NEW SESSION --- {SessionId}",
@@ -461,7 +462,8 @@ private void Client_ReconnectComplete(object sender, EventArgs e)
 
         private static string GetUserCertificateFile(string securityPolicyUri)
         {
-            SecurityPolicyInfo securityPolicy = SecurityPolicies.GetInfo(securityPolicyUri);
+            // GetInfo returns null only for null/empty URI; caller passes a non-empty value.
+            SecurityPolicyInfo securityPolicy = SecurityPolicies.GetInfo(securityPolicyUri)!;
 
             switch (securityPolicy.CertificateKeyAlgorithm)
             {
@@ -480,16 +482,16 @@ private static string GetUserCertificateFile(string securityPolicyUri)
 
         internal sealed class SessionWrapper : IUAClient
         {
-            public ISession Session { get; init; }
+            public required ISession Session { get; init; }
         }
 
         private readonly Lock m_lock = new();
-        private SessionReconnectHandler m_reconnectHandler;
-        private ApplicationConfiguration m_configuration;
-        private SessionWrapper m_wrapper;
+        private SessionReconnectHandler? m_reconnectHandler;
+        private ApplicationConfiguration m_configuration = null!;
+        private SessionWrapper? m_wrapper;
         private ILogger m_logger;
         private ITelemetryContext m_telemetry;
-        private readonly ManualResetEvent m_quitEvent;
+        private readonly ManualResetEvent? m_quitEvent;
 
         private const string kServerUrl = "opc.tcp://localhost:62541";
         private const string kUserName = "sysadmin";

Applications/ConsoleReferenceClient/ConsoleReferenceClient.csproj

@@ -9,6 +9,7 @@
     <Copyright>Copyright © 2004-2024 OPC Foundation, Inc</Copyright>
     <RootNamespace>Quickstarts.ConsoleReferenceClient</RootNamespace>
     <PublishAot Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net10.0'))">true</PublishAot>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="..\ConsoleReferenceServer\ConsoleUtils.cs" Exclude="bin\**;obj\**;**\*.xproj;packages\**" />