Report error when PowerShell built-in modules are missing

src/System.Management.Automation/engine/CommandDiscovery.cs

@@ -1091,24 +1091,27 @@ private static CommandInfo InvokeCommandNotFoundHandler(string commandName, Exec
 
                             if (exportedCommands == null) { continue; }
 
-                            CommandTypes exportedCommandTypes;
                             // Skip if module only has class or other types and no commands.
-                            if (exportedCommands.TryGetValue(commandName, out exportedCommandTypes))
+                            if (exportedCommands.TryGetValue(commandName, out CommandTypes exportedCommandTypes))
                             {
-                                Exception exception;
                                 discoveryTracer.WriteLine("Found in module: {0}", expandedModulePath);
-                                Collection<PSModuleInfo> matchingModule = AutoloadSpecifiedModule(expandedModulePath, context,
+                                Collection<PSModuleInfo> matchingModule = AutoloadSpecifiedModule(
+                                    expandedModulePath,
+                                    context,
                                     cmdletInfo != null ? cmdletInfo.Visibility : SessionStateEntryVisibility.Private,
-                                        out exception);
-                                lastError = exception;
-                                if ((matchingModule == null) || (matchingModule.Count == 0))
+                                    out lastError);
+
+                                if (matchingModule == null || matchingModule.Count == 0)
                                 {
-                                    string error = StringUtil.Format(DiscoveryExceptions.CouldNotAutoImportMatchingModule, commandName, moduleShortName);
-                                    CommandNotFoundException commandNotFound = new CommandNotFoundException(
+                                    string errorMessage = lastError is null
+                                        ? StringUtil.Format(DiscoveryExceptions.CouldNotAutoImportMatchingModule, commandName, moduleShortName)
+                                        : StringUtil.Format(DiscoveryExceptions.CouldNotAutoImportMatchingModuleWithErrorMessage, commandName, moduleShortName, lastError.Message);
+
+                                    throw new CommandNotFoundException(
                                         originalCommandName,
                                         lastError,
-                                        "CouldNotAutoloadMatchingModule", error);
-                                    throw commandNotFound;
+                                        nameof(DiscoveryExceptions.CouldNotAutoImportMatchingModule),
+                                        errorMessage);
                                 }
 
                                 result = LookupCommandInfo(commandName, commandTypes, searchResolutionOptions, commandOrigin, context);

src/System.Management.Automation/engine/InitialSessionState.cs

@@ -1663,11 +1663,6 @@ public InitialSessionState Clone()
 
             ss.DisableFormatUpdates = this.DisableFormatUpdates;
 
-            foreach (var s in this.defaultSnapins)
-            {
-                ss.defaultSnapins.Add(s);
-            }
-
             foreach (var s in ImportedSnapins)
             {
                 ss.ImportedSnapins.Add(s.Key, s.Value);
@@ -3801,34 +3796,26 @@ public PSSnapInInfo ImportPSSnapIn(string name, out PSSnapInException warning)
 
             // Now actually load the snapin...
             PSSnapInInfo snapin = ImportPSSnapIn(newPSSnapIn, out warning);
-            if (snapin != null)
-            {
-                ImportedSnapins.Add(snapin.Name, snapin);
-            }
 
             return snapin;
         }
 
         internal PSSnapInInfo ImportCorePSSnapIn()
         {
-            // Load Microsoft.PowerShell.Core as a snapin
+            // Load Microsoft.PowerShell.Core as a snapin.
             PSSnapInInfo coreSnapin = PSSnapInReader.ReadCoreEngineSnapIn();
-            this.defaultSnapins.Add(coreSnapin);
-            try
-            {
-                PSSnapInException warning;
-                this.ImportPSSnapIn(coreSnapin, out warning);
-            }
-            catch (PSSnapInException)
-            {
-                throw;
-            }
-
+            ImportPSSnapIn(coreSnapin, out _);
             return coreSnapin;
         }
 
         internal PSSnapInInfo ImportPSSnapIn(PSSnapInInfo psSnapInInfo, out PSSnapInException warning)
         {
+            if (psSnapInInfo == null)
+            {
+                ArgumentNullException e = new ArgumentNullException(nameof(psSnapInInfo));
+                throw e;
+            }
+
             // See if the snapin is already loaded. If has been then there will be an entry in the
             // Assemblies list for it already...
             bool reload = true;
@@ -3861,12 +3848,6 @@ internal PSSnapInInfo ImportPSSnapIn(PSSnapInInfo psSnapInInfo, out PSSnapInExce
             Dictionary<string, List<SessionStateAliasEntry>> aliases = null;
             Dictionary<string, SessionStateProviderEntry> providers = null;
 
-            if (psSnapInInfo == null)
-            {
-                ArgumentNullException e = new ArgumentNullException(nameof(psSnapInInfo));
-                throw e;
-            }
-
             Assembly assembly = null;
             string helpFile = null;
 
@@ -3985,29 +3966,16 @@ internal PSSnapInInfo ImportPSSnapIn(PSSnapInInfo psSnapInInfo, out PSSnapInExce
                 }
             }
 
+            ImportedSnapins.Add(psSnapInInfo.Name, psSnapInInfo);
             return psSnapInInfo;
         }
 
         internal List<PSSnapInInfo> GetPSSnapIn(string psSnapinName)
         {
             List<PSSnapInInfo> loadedSnapins = null;
-            foreach (var defaultSnapin in defaultSnapins)
-            {
-                if (defaultSnapin.Name.Equals(psSnapinName, StringComparison.OrdinalIgnoreCase))
-                {
-                    if (loadedSnapins == null)
-                    {
-                        loadedSnapins = new List<PSSnapInInfo>();
-                    }
-
-                    loadedSnapins.Add(defaultSnapin);
-                }
-            }
-
-            PSSnapInInfo importedSnapin = null;
-            if (ImportedSnapins.TryGetValue(psSnapinName, out importedSnapin))
+            if (ImportedSnapins.TryGetValue(psSnapinName, out PSSnapInInfo importedSnapin))
             {
-                if (loadedSnapins == null)
+                if (loadedSnapins is null)
                 {
                     loadedSnapins = new List<PSSnapInInfo>();
                 }
@@ -4886,7 +4854,6 @@ internal static void RemoveAllDrivesForProvider(ProviderInfo pi, SessionStateInt
 
         internal static readonly string CoreSnapin = "Microsoft.PowerShell.Core";
         internal static readonly string CoreModule = "Microsoft.PowerShell.Core";
-        internal Collection<PSSnapInInfo> defaultSnapins = new Collection<PSSnapInInfo>();
 
         // The list of engine modules to create warnings when you try to remove them
         internal static readonly HashSet<string> EngineModules = new HashSet<string>(StringComparer.OrdinalIgnoreCase)

src/System.Management.Automation/engine/Modules/ImportModuleCommand.cs

@@ -762,7 +762,7 @@ private PSModuleInfo ImportModule_LocallyViaName(ImportModuleOptions importModul
                     // Check if module could be a snapin. This was the case for PowerShell version 2 engine modules.
                     if (InitialSessionState.IsEngineModule(name))
                     {
-                        PSSnapInInfo snapin = ModuleCmdletBase.GetEngineSnapIn(Context, name);
+                        PSSnapInInfo snapin = GetEngineSnapIn(Context, name);
 
                         // Return the command if we found a module
                         if (snapin != null)

src/System.Management.Automation/engine/Modules/ModuleCmdletBase.cs

@@ -280,6 +280,18 @@ internal List<WildcardPattern> MatchAll
             "ModuleVersion"
         };
 
+        private static readonly HashSet<string> s_builtInModules = new(StringComparer.OrdinalIgnoreCase)
+        {
+            "CimCmdlets",
+            "Microsoft.PowerShell.Diagnostics",
+            "Microsoft.PowerShell.Host",
+            "Microsoft.PowerShell.Management",
+            "Microsoft.PowerShell.Security",
+            "Microsoft.PowerShell.Utility",
+            "Microsoft.WSMan.Management",
+            "PSDiagnostics",
+        };
+
         /// <summary>
         /// When module manifests lack a CompatiblePSEditions field,
         /// they will be treated as if they have this value.
@@ -2375,17 +2387,15 @@ private IEnumerable<PSModuleInfo> CreateFakeModuleObject(IEnumerable<ModuleSpeci
                 {
                     if (importingModule)
                     {
+                        // In case the module to be loaded in WinCompat mode is a PowerShell built-in module, such as the Utility module,
+                        // we need to check whether the built-in module is actually available in the $PSHOME module path.
+                        // This is because a user may not correctly deploy the built-in modules, and that would result in some confusing
+                        // errors when module auto-loading silently attempts to load those modules from the 'System32' module path.
+                        CheckAvailabilityOfBuiltInModules(ModuleIntrinsics.GetModuleName(moduleManifestPath));
                         IList<PSModuleInfo> moduleProxies = ImportModulesUsingWinCompat(new string[] { moduleManifestPath }, null, options);
 
-                        // we are loading by a single ManifestPath so expect max of 1
-                        if (moduleProxies.Count > 0)
-                        {
-                            return moduleProxies[0];
-                        }
-                        else
-                        {
-                            return null;
-                        }
+                        // We are loading by a single ManifestPath so expect max of 1
+                        return moduleProxies.Count > 0 ? moduleProxies[0] : null;
                     }
                 }
                 else
@@ -3706,7 +3716,7 @@ internal static object IsModuleLoaded(ExecutionContext context, ModuleSpecificat
             // If the RequiredModule is one of the Engine modules, then they could have been loaded as snapins (using InitialSessionState.CreateDefault())
             if (result == null && InitialSessionState.IsEngineModule(requiredModule.Name))
             {
-                result = ModuleCmdletBase.GetEngineSnapIn(context, requiredModule.Name);
+                result = GetEngineSnapIn(context, requiredModule.Name);
                 if (result != null)
                 {
                     loaded = true;
@@ -4883,10 +4893,37 @@ internal static void SyncCurrentLocationHandler(object sender, LocationChangedEv
             }
         }
 
-        internal static System.EventHandler<LocationChangedEventArgs> SyncCurrentLocationDelegate;
+        internal static EventHandler<LocationChangedEventArgs> SyncCurrentLocationDelegate;
 
         internal virtual IList<PSModuleInfo> ImportModulesUsingWinCompat(IEnumerable<string> moduleNames, IEnumerable<ModuleSpecification> moduleFullyQualifiedNames, ImportModuleOptions importModuleOptions) { throw new System.NotImplementedException(); }
 
+        private void CheckAvailabilityOfBuiltInModules(string moduleName)
+        {
+            // Check if the module is a PowerShell built-in module. If so, normalize the module name; if not, skip the module.
+            if (!s_builtInModules.TryGetValue(moduleName, out moduleName))
+            {
+                return;
+            }
+
+            // When it was imported as a snapin, we skip the check because it's OK to not have the module available in such case.
+            if (GetEngineSnapIn(Context, moduleName) is not null)
+            {
+                return;
+            }
+
+            // Check if the module exists in the $PSHOME module path. If not, throws exception.
+            string psHomeModulePath = ModuleIntrinsics.GetPSHomeModulePath();
+            string moduleFolder = Path.Join(psHomeModulePath, moduleName);
+            if (!Directory.Exists(moduleFolder))
+            {
+                throw new InvalidOperationException(
+                    StringUtil.Format(
+                        Modules.CannotFindBuiltInModules,
+                        moduleName,
+                        psHomeModulePath));
+            }
+        }
+
         private void RemoveTypesAndFormatting(
             IList<string> formatFilesToRemove,
             IList<string> typeFilesToRemove)
@@ -7364,19 +7401,9 @@ private static bool HasInvalidCharacters(string commandName)
         /// </summary>
         internal static PSSnapInInfo GetEngineSnapIn(ExecutionContext context, string name)
         {
-            HashSet<PSSnapInInfo> snapinSet = new HashSet<PSSnapInInfo>();
-            List<CmdletInfo> cmdlets = context.SessionState.InvokeCommand.GetCmdlets();
-            foreach (CmdletInfo cmdlet in cmdlets)
-            {
-                PSSnapInInfo snapin = cmdlet.PSSnapIn;
-                if (snapin != null && !snapinSet.Contains(snapin))
-                    snapinSet.Add(snapin);
-            }
-
-            foreach (PSSnapInInfo snapin in snapinSet)
+            if (context.CurrentRunspace.InitialSessionState.ImportedSnapins.TryGetValue(name, out PSSnapInInfo snapin))
             {
-                if (string.Equals(snapin.Name, name, StringComparison.OrdinalIgnoreCase))
-                    return snapin;
+                return snapin;
             }
 
             return null;

src/System.Management.Automation/engine/Modules/ModuleIntrinsics.cs

@@ -976,20 +976,10 @@ internal static string GetPSHomeModulePath()
             try
             {
                 string psHome = Utils.DefaultPowerShellAppBase;
-                if (!string.IsNullOrEmpty(psHome))
-                {
-                    // Win8: 584267 Powershell Modules are listed twice in x86, and cannot be removed
-                    // This happens because ModuleTable uses Path as the key and CBS installer
-                    // expands the path to include "SysWOW64" (for
-                    // HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\PowerShell\3\PowerShellEngine ApplicationBase).
-                    // Because of this, the module that is getting loaded during startup (through LocalRunspace)
-                    // is using "SysWow64" in the key. Later, when Import-Module is called, it loads the
-                    // module using ""System32" in the key.
 #if !UNIX
-                    psHome = psHome.ToLowerInvariant().Replace("\\syswow64\\", "\\system32\\");
+                psHome = psHome.ToLowerInvariant().Replace(@"\syswow64\", @"\system32\");
 #endif
-                    Interlocked.CompareExchange(ref s_psHomeModulePath, Path.Combine(psHome, "Modules"), null);
-                }
+                Interlocked.CompareExchange(ref s_psHomeModulePath, Path.Combine(psHome, "Modules"), null);
             }
             catch (System.Security.SecurityException)
             {

src/System.Management.Automation/engine/Modules/ModuleUtils.cs

@@ -121,7 +121,7 @@ internal static IEnumerable<string> GetAllAvailableModuleFiles(string topDirecto
 #if UNIX
             return true;
 #else
-            if (!ModuleUtils.IsOnSystem32ModulePath(moduleManifestPath))
+            if (!IsOnSystem32ModulePath(moduleManifestPath))
             {
                 return true;
             }

src/System.Management.Automation/engine/remoting/client/remoterunspace.cs

@@ -221,11 +221,7 @@ public override InitialSessionState InitialSessionState
         {
             get
             {
-#pragma warning disable 56503
-
                 throw PSTraceSource.NewNotImplementedException();
-
-#pragma warning restore 56503
             }
         }
 
@@ -236,11 +232,7 @@ public override JobManager JobManager
         {
             get
             {
-#pragma warning disable 56503
-
                 throw PSTraceSource.NewNotImplementedException();
-
-#pragma warning restore 56503
             }
         }
 

src/System.Management.Automation/resources/DiscoveryExceptions.resx

@@ -206,6 +206,10 @@ The #requires statement must be in one of the following formats:
   <data name="CouldNotAutoImportMatchingModule" xml:space="preserve">
     <value>The '{0}' command was found in the module '{1}', but the module could not be loaded. For more information, run 'Import-Module {1}'.</value>
   </data>
+  <data name="CouldNotAutoImportMatchingModuleWithErrorMessage" xml:space="preserve">
+    <value>The '{0}' command was found in the module '{1}', but the module could not be loaded due to the following error: [{2}]
+For more information, run 'Import-Module {1}'.</value>
+  </data>
   <data name="CouldNotAutoImportModule" xml:space="preserve">
     <value>The module '{0}' could not be loaded. For more information, run 'Import-Module {0}'.</value>
   </data>

src/System.Management.Automation/resources/Modules.resx

@@ -624,4 +624,7 @@
   <data name="CannotCreateModuleWithScriptBlock" xml:space="preserve">
     <value>Cannot create new module while the session is in ConstrainedLanguage mode.</value>
   </data>
+  <data name="CannotFindBuiltInModules" xml:space="preserve">
+    <value>The built-in module '{0}' cannot be found under the $PSHOME module path '{1}'. Please make sure the PowerShell built-in modules are available because they are required for PowerShell to function properly.</value>
+  </data>
 </root>