ModuleCmdletBase.cs

/********************************************************************++
Copyright (c) Microsoft Corporation.  All rights reserved.
--********************************************************************/

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Management.Automation;
using System.Management.Automation.Internal;
using System.Management.Automation.Runspaces;
using System.Management.Automation.Security;
using System.Reflection;
using System.Text;
using System.Xml;
using Microsoft.PowerShell.Cmdletization;
using Dbg = System.Management.Automation.Diagnostics;

//
// Now define the set of commands for manipulating modules.
//
namespace Microsoft.PowerShell.Commands
{
    #region ModuleCmdletBase class

    /// <summary>
    /// This is the base class for some of the module cmdlets. It contains a number of
    /// utility functions for these classes.
    /// </summary>
    public class ModuleCmdletBase : PSCmdlet
    {
        /// <summary>
        /// Flags defining how a module manifest should be processed
        /// </summary>
        [Flags]
        internal enum ManifestProcessingFlags
        {
            /// <summary>
            /// Write errors (otherwise no non-terminating-errors are written)
            /// </summary>
            WriteErrors = 0x1,

            /// <summary>
            /// Return null on first error (otherwise we try to process other elements of the manifest)
            /// </summary>
            NullOnFirstError = 0x2,

            /// <summary>
            /// Load elements of the manifest (i.e. types/format.ps1xml, nested modules, etc.)
            /// </summary>
            LoadElements = 0x4,

            /// <summary>
            /// Write warnings
            /// </summary>
            WriteWarnings = 0x8,

            /// <summary>
            /// Force full module manifest processing.
            /// </summary>
            Force = 0x10,

            /// <summary>
            /// Ignore PowerShellHostName and PowerShellHostVersion while
            /// processing Manifest fields.
            /// This is used for GetModule where loading elements does not happen.
            /// </summary>
            IgnoreHostNameAndHostVersion = 0x20,
        }

        /// <summary>
        /// Options set during module import
        /// </summary>
        [SuppressMessage("Microsoft.Performance", "CA1815:OverrideEqualsAndOperatorEqualsOnValueTypes")]
        protected internal struct ImportModuleOptions
        {
            /// <summary>
            /// Holds the value of NoClobber parameter in Import-Module
            /// This is used when importing modules.
            /// </summary>
            internal bool NoClobber;

            /// <summary>
            /// If Scope parameter is Local, this is true.
            /// </summary>
            internal bool Local;

            /// <summary>
            /// Win8:90779
            /// ServiceCore assembly is automatically imported as a nested module to process the NestedModules/RootModules/RequiredAssemblies fields in module manifests.
            /// This property is set to ensure that Import-Module of a manifest module does not expose "Import-psworkflow" cmdlet.
            ///  </summary>
            internal bool ServiceCoreAutoAdded;
        }

        /// <summary>
        /// This parameter specified a prefix used to modify names of imported commands
        /// </summary>
        internal string BasePrefix { set; get; } = string.Empty;

        /// <summary>
        /// Flags -force operations
        /// </summary>
        internal bool BaseForce { get; set; }

        /// <summary>
        /// Flags -global operations (affects what gets returned by TargetSessionState)
        /// </summary>
        internal bool BaseGlobal { get; set; }

        internal SessionState TargetSessionState
        {
            get
            {
                if (BaseGlobal)
                {
                    return this.Context.TopLevelSessionState.PublicSessionState;
                }
                else
                {
                    return this.Context.SessionState;
                }
            }
        }

        /// <summary>
        /// Flags -passthru operations
        /// </summary>
        internal bool BasePassThru { get; set; }

        /// <summary>
        /// Flags -passthru operations
        /// </summary>
        internal bool BaseAsCustomObject { get; set; }

        /// <summary>
        /// Wildcard patterns for the function to import
        /// </summary>
        [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification = "Cmdlet parameters.")]
        internal List<WildcardPattern> BaseFunctionPatterns { get; set; }

        /// <summary>
        /// Wildcard patterns for the cmdlets to import
        /// </summary>
        [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification = "Cmdlet parameters.")]
        internal List<WildcardPattern> BaseCmdletPatterns { get; set; }

        /// <summary>
        /// Wildcard patterns for the variables to import
        /// </summary>
        [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification = "Cmdlet parameters.")]
        internal List<WildcardPattern> BaseVariablePatterns { get; set; }

        /// <summary>
        /// Wildcard patterns for the aliases to import
        /// </summary>
        [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification = "Cmdlet parameters.")]
        internal List<WildcardPattern> BaseAliasPatterns { get; set; }

        /// <summary>
        /// The minimum version number to check the module against. Used the underlying property
        /// for derived cmdlet parameters.
        /// </summary>
        internal Version BaseMinimumVersion { get; set; }

        /// <summary>
        /// The maximum version number to check the module against. Used the underlying property
        /// for derived cmdlet parameters.
        /// </summary>
        internal Version BaseMaximumVersion { get; set; }

        /// <summary>
        /// The version number to check the module against. Used the underlying property
        /// for derived cmdlet parameters.
        /// </summary>
        internal Version BaseRequiredVersion { get; set; }

        /// <summary>
        /// The Guid to check the module against. Used the underlying property
        /// for derived cmdlet parameters.
        /// </summary>
        internal Guid? BaseGuid { get; set; }

        /// <summary>
        /// The arguments to pass to the scriptblock used to create the module
        /// </summary>
        [SuppressMessage("Microsoft.Performance", "CA1819:PropertiesShouldNotReturnArrays", Justification = "Cmdlets use arrays for parameters.")]
        protected object[] BaseArgumentList { get; set; }

        /// <summary>
        /// Disable warnings on cmdlet and function names that have non-standard verbs
        /// or non-standard characters in the noun.
        /// </summary>
        protected bool BaseDisableNameChecking { get; set; } = true;

        /// <summary>
        /// Add module path to app domain level module path cache if name is not rooted
        /// </summary>
        protected bool AddToAppDomainLevelCache { get; set; } = false;

        /// <summary>
        /// A handy match all pattern used to initialize various import and export lists...
        /// </summary>
        internal List<WildcardPattern> MatchAll
        {
            get
            {
                if (_matchAll == null)
                {
                    _matchAll = new List<WildcardPattern>();
                    _matchAll.Add(WildcardPattern.Get("*", WildcardOptions.IgnoreCase));
                }
                return _matchAll;
            }
        }
        private List<WildcardPattern> _matchAll;

        // The list of commands permitted in a module manifest
        internal static string[] PermittedCmdlets = new string[] {
            "Import-LocalizedData", "ConvertFrom-StringData", "Write-Host", "Out-Host", "Join-Path" };

        internal static string[] ModuleManifestMembers = new string[] {
            "ModuleToProcess",
            "NestedModules",
            "GUID",
            "Author",
            "CompanyName",
            "Copyright",
            "ModuleVersion",
            "Description",
            "PowerShellVersion",
            "PowerShellHostName",
            "PowerShellHostVersion",
            "CLRVersion",
            "DotNetFrameworkVersion",
            "ProcessorArchitecture",
            "RequiredModules",
            "TypesToProcess",
            "FormatsToProcess",
            "ScriptsToProcess",
            "PrivateData",
            "RequiredAssemblies",
            "ModuleList",
            "FileList",
            "FunctionsToExport",
            "VariablesToExport",
            "AliasesToExport",
            "CmdletsToExport",
            "DscResourcesToExport",
            "CompatiblePSEditions",
            "HelpInfoURI",
            "RootModule",
            "DefaultCommandPrefix"
        };

        private static string[] s_moduleVersionMembers = new string[] {
            "ModuleName",
            "GUID",
            "ModuleVersion"
        };

        private static List<string> s_serviceCoreAssemblyCmdlets = new List<string>(new string[] {
            "Microsoft.PowerShell.Workflow.ServiceCore\\Import-PSWorkflow",
            "Microsoft.PowerShell.Workflow.ServiceCore\\New-PSWorkflowExecutionOption",
        });

        private Dictionary<string, PSModuleInfo> _currentlyProcessingModules = new Dictionary<string, PSModuleInfo>();

        internal bool LoadUsingModulePath(bool found, IEnumerable<string> modulePath, string name, SessionState ss,
            ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags, out PSModuleInfo module)
        {
            return LoadUsingModulePath(null, found, modulePath, name, ss, options, manifestProcessingFlags, out module);
        }

        internal bool LoadUsingModulePath(PSModuleInfo parentModule, bool found, IEnumerable<string> modulePath, string name, SessionState ss,
            ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags, out PSModuleInfo module)
        {
            string extension = Path.GetExtension(name);
            string fileBaseName;
            module = null;
            if (String.IsNullOrEmpty(extension) || !ModuleIntrinsics.IsPowerShellModuleExtension(extension))
            {
                fileBaseName = name;
                extension = null;
            }
            else
                fileBaseName = name.Substring(0, name.Length - extension.Length);

            // Now search using the module path...
            foreach (string path in modulePath)
            {
                // a name takes the form of .../moduleDir/moduleName.<ext>
                // if only one name has been specified, then the moduleDir
                // and moduleName are identical and repeated...
                // Also append th ename if the path currently points at a directory
                string qualifiedPath = Path.Combine(path, fileBaseName);

                // Load the latest valid version if it is a multi-version module directory
                module = LoadUsingMultiVersionModuleBase(qualifiedPath, manifestProcessingFlags, options, out found);

                if (!found)
                {
                    if (name.IndexOfAny(Utils.Separators.Directory) == -1)
                    {
                        qualifiedPath = Path.Combine(qualifiedPath, fileBaseName);
                    }
                    else if (Directory.Exists(qualifiedPath))
                    {
                        // if it points to a directory, add the basename back onto the path...
                        qualifiedPath = Path.Combine(qualifiedPath, Path.GetFileName(fileBaseName));
                    }

                    module = LoadUsingExtensions(parentModule, name, qualifiedPath, extension, null, this.BasePrefix, ss, options, manifestProcessingFlags, out found);
                }

                if (found)
                {
                    break;
                }
            }

            if (found)
            {
                // Cache the module's exported commands after importing it, or if the -Refresh flag is used on
                // "Get-Module -List"
                if ((module != null) && !module.HadErrorsLoading)
                {
                    if (module.ExportedWorkflows != null && module.ExportedWorkflows.Count > 0 && Utils.IsRunningFromSysWOW64())
                    {
                        throw new NotSupportedException(AutomationExceptions.WorkflowDoesNotSupportWOW64);
                    }

                    AnalysisCache.CacheModuleExports(module, Context);
                }
            }
            return found;
        }

        /// <summary>
        /// Loads the latest valid version if moduleBase is a multi-versioned module directory
        /// </summary>
        /// <param name="moduleBase">module directory path</param>
        /// <param name="manifestProcessingFlags">The flag that indicate manifest processing option</param>
        /// <param name="importModuleOptions">The set of options that are used while importing a module</param>
        /// <param name="found">True if a module was found</param>
        /// <returns></returns>
        internal PSModuleInfo LoadUsingMultiVersionModuleBase(string moduleBase, ManifestProcessingFlags manifestProcessingFlags, ImportModuleOptions importModuleOptions, out bool found)
        {
            PSModuleInfo foundModule = null;
            found = false;

            foreach (var version in ModuleUtils.GetModuleVersionSubfolders(moduleBase))
            {
                // Skip the version folder if it is not equal to the required version or does not satisfy the minimum/maximum version criteria
                if ((BaseRequiredVersion != null && !BaseRequiredVersion.Equals(version))
                    || (BaseMinimumVersion != null && BaseRequiredVersion == null && version < BaseMinimumVersion)
                    || (BaseMaximumVersion != null && BaseRequiredVersion == null && version > BaseMaximumVersion))
                {
                    continue;
                }

                var qualifiedPathWithVersion = Path.Combine(moduleBase,
                                                            Path.Combine(version.ToString(), Path.GetFileName(moduleBase)));
                string manifestPath = qualifiedPathWithVersion + StringLiterals.PowerShellDataFileExtension;
                var isValidModuleVersion = false;
                if (File.Exists(manifestPath))
                {
                    isValidModuleVersion = version.Equals(ModuleIntrinsics.GetManifestModuleVersion(manifestPath));

                    if (isValidModuleVersion)
                    {
                        foundModule = LoadUsingExtensions(null, moduleBase, qualifiedPathWithVersion,
                                                            StringLiterals.PowerShellDataFileExtension,
                                                            null,
                                                            this.BasePrefix, /*SessionState*/ null,
                                                            importModuleOptions,
                                                            manifestProcessingFlags,
                                                            out found);
                        if (found)
                        {
                            break;
                        }
                    }
                }

                if (!isValidModuleVersion)
                {
                    WriteVerbose(String.Format(CultureInfo.InvariantCulture, Modules.SkippingInvalidModuleVersionFolder,
                                                version.ToString(), moduleBase));
                }
            }

            return foundModule;
        }

        /// <summary>
        /// Load and execute the manifest psd1 file or a localized manifest psd1 file.
        /// </summary>
        private Hashtable LoadModuleManifestData(
            ExternalScriptInfo scriptInfo,
            string[] validMembers,
            ManifestProcessingFlags manifestProcessingFlags,
            ref bool containedErrors)
        {
            try
            {
                return LoadModuleManifestData(scriptInfo.Path, scriptInfo.ScriptBlock, validMembers, manifestProcessingFlags, ref containedErrors);
            }
            catch (RuntimeException pe)
            {
                if (0 != (manifestProcessingFlags & ManifestProcessingFlags.WriteErrors))
                {
                    string message = StringUtil.Format(Modules.InvalidModuleManifest, scriptInfo.Path, pe.Message);
                    MissingMemberException mm = new MissingMemberException(message);
                    ErrorRecord er = new ErrorRecord(mm, "Modules_InvalidManifest",
                        ErrorCategory.ResourceUnavailable, scriptInfo.Path);
                    WriteError(er);
                }
                containedErrors = true;
                return null;
            }
        }

        /// <summary>
        /// Extra variables that are allowed to be referenced in module manifest file
        /// </summary>
        private static readonly string[] s_extraAllowedVariables = new string[] { "PSScriptRoot", "PSEdition" };

        /// <summary>
        /// Load and execute the manifest psd1 file or a localized manifest psd1 file.
        /// </summary>
        internal Hashtable LoadModuleManifestData(
            string moduleManifestPath,
            ScriptBlock scriptBlock,
            string[] validMembers,
            ManifestProcessingFlags manifestProcessingFlags,
            ref bool containedErrors)
        {
            string message;

            var importingModule = 0 != (manifestProcessingFlags & ManifestProcessingFlags.LoadElements);
            var writingErrors = 0 != (manifestProcessingFlags & ManifestProcessingFlags.WriteErrors);

            // Load the data file(s) to get the module info...
            try
            {
                scriptBlock.CheckRestrictedLanguage(PermittedCmdlets, s_extraAllowedVariables, true);
            }
            catch (RuntimeException pe)
            {
                if (writingErrors)
                {
                    message = StringUtil.Format(Modules.InvalidModuleManifest, moduleManifestPath, pe.Message);
                    MissingMemberException mm = new MissingMemberException(message);
                    ErrorRecord er = new ErrorRecord(mm, "Modules_InvalidManifest",
                        ErrorCategory.ResourceUnavailable, moduleManifestPath);
                    WriteError(er);
                }
                containedErrors = true;
                return null;
            }

            object result;
            object oldPSScriptRoot = Context.GetVariableValue(SpecialVariables.PSScriptRootVarPath);
            object oldPSCommandPath = Context.GetVariableValue(SpecialVariables.PSCommandPathVarPath);
            ArrayList errors = (ArrayList)Context.GetVariableValue(SpecialVariables.ErrorVarPath);
            int oldErrorCount = errors.Count;

            try
            {
                // Set the PSScriptRoot variable in the modules session state
                Context.SetVariable(SpecialVariables.PSScriptRootVarPath, Path.GetDirectoryName(moduleManifestPath));
                Context.SetVariable(SpecialVariables.PSCommandPathVarPath, moduleManifestPath);

                result = PSObject.Base(scriptBlock.InvokeReturnAsIs());
            }
            finally
            {
                Context.SetVariable(SpecialVariables.PSScriptRootVarPath, oldPSScriptRoot);
                Context.SetVariable(SpecialVariables.PSCommandPathVarPath, oldPSCommandPath);

                // We do not want any exceptions to show up in user's session state. So, we are removing errors in the finally block.
                // If we're not loading the manifest (and are examining it), prevent errors from showing up in
                // the user's session.
                if (!importingModule)
                {
                    while (errors.Count > oldErrorCount) { errors.RemoveAt(0); }
                }
            }

            Hashtable data = result as Hashtable;
            if (data == null)
            {
                if (writingErrors)
                {
                    message = StringUtil.Format(Modules.EmptyModuleManifest, moduleManifestPath);
                    ArgumentException ae = new ArgumentException(message);
                    ErrorRecord er = new ErrorRecord(ae, "Modules_InvalidManifest",
                        ErrorCategory.ResourceUnavailable, moduleManifestPath);
                    WriteError(er);
                }
                containedErrors = true;
                return null;
            }

            // MSFT:873446 Create a case insensitive comparer based hashtable to help
            // with case-insensitive comparison of keys.
            data = new Hashtable(data, StringComparer.OrdinalIgnoreCase);
            if (validMembers != null && !ValidateManifestHash(data, validMembers, moduleManifestPath, manifestProcessingFlags))
            {
                containedErrors = true;
                if (0 != (manifestProcessingFlags & ManifestProcessingFlags.NullOnFirstError))
                    return null;
            }

            return data;
        }

        /// <summary>
        /// Verify the hash contains only valid members.  Write an error and return false if it is not valid.
        /// </summary>
        private bool ValidateManifestHash(
            Hashtable data,
            string[] validMembers,
            string moduleManifestPath,
            ManifestProcessingFlags manifestProcessingFlags)
        {
            bool result = true;

            StringBuilder badKeys = new StringBuilder();
            foreach (string s in data.Keys)
            {
                bool found = false;

                foreach (string member in validMembers)
                {
                    if (s.Equals(member, StringComparison.OrdinalIgnoreCase))
                    {
                        found = true;
                    }
                }

                if (!found)
                {
                    if (badKeys.Length > 0)
                        badKeys.Append(", ");
                    badKeys.Append("'");
                    badKeys.Append(s);
                    badKeys.Append("'");
                }
            }
            if (badKeys.Length > 0)
            {
                result = false;
                string message = null;

                if (0 != (manifestProcessingFlags & ManifestProcessingFlags.WriteErrors))
                {
                    // Check for PowerShell Version before checking other keys
                    // If a PowerShellVersion exists and does not match the requirements, then the error is InsufficientPowerShellVersion
                    // Else, the error is InvalidManifestMember

                    Version powerShellVersion;
                    Version currentPowerShellVersion = PSVersionInfo.PSVersion;
                    if (GetScalarFromData<Version>(data, moduleManifestPath, "PowerShellVersion", manifestProcessingFlags, out powerShellVersion) &&
                        currentPowerShellVersion < powerShellVersion)
                    {
                        message = StringUtil.Format(Modules.ModuleManifestInsufficientPowerShellVersion,
                                                    currentPowerShellVersion,
                                                    moduleManifestPath, powerShellVersion);
                        InvalidOperationException ioe = new InvalidOperationException(message);
                        ErrorRecord er = new ErrorRecord(ioe, "Modules_InsufficientPowerShellVersion",
                                                         ErrorCategory.ResourceUnavailable, moduleManifestPath);
                        WriteError(er);
                    }
                    else
                    {
                        StringBuilder validMembersString = new StringBuilder("'");
                        validMembersString.Append(validMembers[0]);
                        for (int i = 1; i < validMembers.Length; i++)
                        {
                            validMembersString.Append("', '");
                            validMembersString.Append(validMembers[i]);
                        }
                        validMembersString.Append("'");
                        message = StringUtil.Format(Modules.InvalidModuleManifestMember, moduleManifestPath, validMembersString, badKeys);
                        InvalidOperationException ioe = new InvalidOperationException(message);
                        ErrorRecord er = new ErrorRecord(ioe, "Modules_InvalidManifestMember",
                            ErrorCategory.InvalidData, moduleManifestPath);
                        WriteError(er);
                    }
                }
            }
            return result;
        }

        private PSModuleInfo LoadModuleNamedInManifest(PSModuleInfo parentModule, ModuleSpecification moduleSpecification, string moduleBase, bool searchModulePath,
            string prefix, SessionState ss, ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags, bool loadTypesFiles,
            bool loadFormatFiles, object privateData, out bool found, string shortModuleName)
        {
            PSModuleInfo module = null;
            PSModuleInfo tempModuleInfoFromVerification = null;
            found = false;
            bool moduleFileFound = false;
            bool wasRooted = false;
            Version savedBaseMinimumVersion = BaseMinimumVersion;
            Version savedBaseMaximumVersion = BaseMaximumVersion;
            Version savedBaseRequiredVersion = BaseRequiredVersion;
            Guid? savedBaseGuid = BaseGuid;

            var importingModule = 0 != (manifestProcessingFlags & ManifestProcessingFlags.LoadElements);
            string extension = Path.GetExtension(moduleSpecification.Name);
            // First check for fully-qualified paths - either absolute or relative
            string rootedPath = ResolveRootedFilePath(moduleSpecification.Name, this.Context);
            if (String.IsNullOrEmpty(rootedPath))
            {
                rootedPath = FixupFileName(moduleBase, moduleSpecification.Name, extension);
            }
            else
            {
                wasRooted = true;
            }

            try
            {
                this.Context.Modules.IncrementModuleNestingDepth(this, rootedPath);
                BaseMinimumVersion = null;
                BaseMaximumVersion = null;
                BaseRequiredVersion = null;
                BaseGuid = null;

                // See if it's one of the powershell module extensions...
                if (!ModuleIntrinsics.IsPowerShellModuleExtension(extension))
                {
                    // If the file exits, and it does not have a powershell module extension, we know for sure that the file is not a valid module
                    if (File.Exists(rootedPath))
                    {
                        PSInvalidOperationException invalidOperation = PSTraceSource.NewInvalidOperationException(
                                                                Modules.ManifestMemberNotValid,
                                                                moduleSpecification.Name,
                                                                "NestedModules",
                                                                parentModule.Path,
                                                                StringUtil.Format(Modules.InvalidModuleExtension, extension, moduleSpecification.Name),
                                                                                    ModuleIntrinsics.GetModuleName(parentModule.Path));
                        invalidOperation.SetErrorId("Modules_InvalidModuleExtension");
                        throw invalidOperation;
                    }
                    extension = null;
                }

                // Now load the module from the module directory first...
                if (extension == null)
                {
                    // No extension so we'll have to search using the extensions
                    //
                    if (VerifyIfNestedModuleIsAvailable(moduleSpecification, rootedPath, /*extension*/null, out tempModuleInfoFromVerification))
                    {
                        module = LoadUsingExtensions(
                            parentModule,
                            moduleSpecification.Name,
                            rootedPath, // fileBaseName
                            /*extension*/null,
                            moduleBase, // not using base from tempModuleInfoFromVerification as we are looking under moduleBase directory
                            prefix,
                            ss,
                            options,
                            manifestProcessingFlags,
                            out found,
                            out moduleFileFound);
                    }

                    // Win8: 262157 - Import-Module is giving errors while loading Nested Modules. (This is a V2 bug)
                    // NestedModules = 'test2' ---> test2 is a directory under current module directory (e.g - Test1)
                    // We also need to look for Test1\Test2\Test2.(psd1/psm1/dll)
                    // With the call above, we are only looking at Test1\Test2.(psd1/psm1/dll)
                    if (found == false && moduleFileFound == false)
                    {
                        string newRootedPath = Path.Combine(rootedPath, moduleSpecification.Name);
                        string newModuleBase = Path.Combine(moduleBase, moduleSpecification.Name);
                        if (VerifyIfNestedModuleIsAvailable(moduleSpecification, newRootedPath, /*extension*/null, out tempModuleInfoFromVerification))
                        {
                            module = LoadUsingExtensions(
                                parentModule,
                                moduleSpecification.Name,
                                newRootedPath, // fileBaseName
                                /*extension*/ null,
                                newModuleBase, // not using base from tempModuleInfoFromVerification as we are looking under moduleBase directory
                                prefix,
                                ss,
                                options,
                                manifestProcessingFlags,
                                out found,
                                out moduleFileFound);
                        }
                    }
                }
                else
                {
                    // Ok - we have a complete file name so load that...
                    if (VerifyIfNestedModuleIsAvailable(moduleSpecification, rootedPath, extension, out tempModuleInfoFromVerification))
                    {
                        module = LoadModule(
                            parentModule,
                            rootedPath, // fileName
                            moduleBase, // not using base from tempModuleInfoFromVerification as we have a complete file name
                            prefix,
                            ss,
                            privateData,
                            ref options,
                            manifestProcessingFlags,
                            out found,
                            out moduleFileFound);
                    }

                    // Win8: 262157 - Import-Module is giving errors while loading Nested Modules. (This is a V2 bug)
                    // Only look for the file if the file was not found with the previous search
                    if (found == false && moduleFileFound == false)
                    {
                        string newRootedPath = Path.Combine(rootedPath, moduleSpecification.Name);
                        string newModuleBase = Path.Combine(moduleBase, moduleSpecification.Name);
                        if (VerifyIfNestedModuleIsAvailable(moduleSpecification, newRootedPath, extension, out tempModuleInfoFromVerification))
                        {
                            module = LoadModule(
                                parentModule,
                                newRootedPath, // fileName
                                newModuleBase, // not using base from tempModuleInfoFromVerification as we are looking under moduleBase directory
                                prefix,
                                ss,
                                privateData,
                                ref options,
                                manifestProcessingFlags,
                                out found,
                                out moduleFileFound);
                        }
                    }
                }

                // The rooted files wasn't found, so don't search anymore...
                if (found == false && wasRooted == true)
                    return null;

                if (searchModulePath && found == false && moduleFileFound == false)
                {
                    if (VerifyIfNestedModuleIsAvailable(moduleSpecification, null, null, out tempModuleInfoFromVerification))
                    {
                        IEnumerable<string> modulePath = null;
                        if (tempModuleInfoFromVerification != null)
                        {
                            var subdirName = Path.GetFileName(tempModuleInfoFromVerification.ModuleBase);
                            Version version;
                            if (Version.TryParse(subdirName, out version))
                            {
                                var moduleBaseWithoutVersion = Path.GetDirectoryName(tempModuleInfoFromVerification.ModuleBase);

                                modulePath = new string[]
                                {
                                    Path.GetDirectoryName(moduleBaseWithoutVersion),
                                    moduleBaseWithoutVersion
                                };
                            }
                            else
                            {
                                modulePath = new string[]
                                {
                                    Path.GetDirectoryName(tempModuleInfoFromVerification.ModuleBase),
                                    tempModuleInfoFromVerification.ModuleBase
                                };
                            }
                        }
                        else
                        {
                            modulePath = ModuleIntrinsics.GetModulePath(false, this.Context);
                        }

                        // Otherwise try the module path
                        found = LoadUsingModulePath(parentModule, found, modulePath,
                                                    moduleSpecification.Name, ss,
                                                    options, manifestProcessingFlags, out module);
                    }
                }

                // At this point, we haven't found an actual module, so try loading it as a
                // PSSnapIn and then finally as an assembly in the GAC...
                if ((found == false) && (moduleSpecification.Guid == null) && (moduleSpecification.Version == null) && (moduleSpecification.RequiredVersion == null) && (moduleSpecification.MaximumVersion == null))
                {
                    // If we are in module analysis and the parent module declares non-wildcarded ExportedCmdlets, then we don't need to
                    // actually process the binary module.
                    bool shouldLoadModule = true;

                    if ((parentModule != null) && !importingModule)
                    {
                        if ((parentModule.ExportedCmdlets != null) && (parentModule.ExportedCmdlets.Count > 0))
                        {
                            shouldLoadModule = false;

                            foreach (string exportedCmdlet in parentModule.ExportedCmdlets.Keys)
                            {
                                if (WildcardPattern.ContainsWildcardCharacters(exportedCmdlet))
                                {
                                    shouldLoadModule = true;
                                    break;
                                }
                            }

                            found = true;
                        }
                    }

                    if (shouldLoadModule)
                    {
                        try
                        {
                            // At this point, we are already exhaust all possible ways to load the nested module. The last option is to load it as a binary module/snapin.
                            module = LoadBinaryModule(
                                parentModule,
                                true, // trySnapInName
                                moduleSpecification.Name,
                                null, // fileName
                                null, // assemblyToLoad
                                moduleBase,
                                ss,
                                options,
                                manifestProcessingFlags,
                                prefix,
                                loadTypesFiles,
                                loadFormatFiles,
                                out found,
                                shortModuleName, false);
                        }
                        catch (FileNotFoundException)
                        {
                            // Loading the nested module as a pssnapin or assembly is our last attempt to resolve the nested module.
                            // If we catch 'FileNotFoundException', it simply means that our last attempt failed because we couldn't find such a pssnapin or assembly.
                            // In this case, we can safely ignore this exception and throw a 'Modules_ModuleFileNotFound' error.
                        }

                        if ((module != null) && importingModule)
                        {
                            AddModuleToModuleTables(this.Context, this.TargetSessionState.Internal, module);
                        }
                    }
                }

                return module;
            }
            finally
            {
                BaseMinimumVersion = savedBaseMinimumVersion;
                BaseMaximumVersion = savedBaseMaximumVersion;
                BaseRequiredVersion = savedBaseRequiredVersion;
                BaseGuid = savedBaseGuid;
                this.Context.Modules.DecrementModuleNestingCount();
            }
        }

        internal List<PSModuleInfo> GetModule(string[] names, bool all, bool refresh)
        {
            List<PSModuleInfo> modulesToReturn = new List<PSModuleInfo>();

            // Two lists - one to hold Module Paths and one to hold Module Names
            // For Module Paths, we don't do any path resolution
            List<String> modulePaths = new List<String>();
            List<String> moduleNames = new List<String>();

            if (names != null)
            {
                foreach (var n in names)
                {
                    if (n.IndexOf(StringLiterals.DefaultPathSeparator) != -1 || n.IndexOf(StringLiterals.AlternatePathSeparator) != -1)
                    {
                        modulePaths.Add(n);
                    }
                    else
                    {
                        moduleNames.Add(n);
                    }
                }
                modulesToReturn.AddRange(GetModuleForRootedPaths(modulePaths.ToArray(), all, refresh));
            }

            // If no names were passed to this function, then this API will return list of all available modules
            if (names == null || moduleNames.Count > 0)
            {
                modulesToReturn.AddRange(GetModuleForNonRootedPaths(moduleNames.ToArray(), all, refresh));
            }

            return modulesToReturn;
        }

        private IEnumerable<PSModuleInfo> GetModuleForNonRootedPaths(string[] names, bool all, bool refresh)
        {
            const WildcardOptions wildcardOptions = WildcardOptions.IgnoreCase | WildcardOptions.CultureInvariant;
            IEnumerable<WildcardPattern> patternList = SessionStateUtilities.CreateWildcardsFromStrings(names, wildcardOptions);

            Dictionary<String, List<PSModuleInfo>> availableModules = GetAvailableLocallyModulesCore(names, all, refresh);
            foreach (var entry in availableModules)
            {
                foreach (PSModuleInfo module in entry.Value)
                {
                    if (SessionStateUtilities.MatchesAnyWildcardPattern(module.Name, patternList, true))
                    {
                        yield return module;
                    }
                }
            }
        }

        private IEnumerable<PSModuleInfo> GetModuleForRootedPaths(string[] modulePaths, bool all, bool refresh)
        {
            // This is to filter out duplicate modules
            var modules = new HashSet<string>(StringComparer.OrdinalIgnoreCase);

            foreach (string mp in modulePaths)
            {
                bool containsWildCards = false;

                string modulePath = mp.TrimEnd(Utils.Separators.Backslash);

                // If the given path contains wildcards, we won't throw error if no match module path is found.
                if (WildcardPattern.ContainsWildcardCharacters(modulePath))
                {
                    containsWildCards = true;
                }

                //Now we resolve the possible paths in case it is relative path/path contains wildcards
                var modulePathCollection = GetResolvedPathCollection(modulePath, this.Context);


                if (modulePathCollection != null)
                {
                    foreach (string resolvedModulePath in modulePathCollection)
                    {
                        string moduleName = Path.GetFileName(resolvedModulePath);
                        bool isDirectory = Utils.NativeDirectoryExists(resolvedModulePath);

                        // If the given path is a valid module file, we will load the specific file
                        if (!isDirectory && ModuleIntrinsics.IsPowerShellModuleExtension(Path.GetExtension(moduleName)))
                        {
                            PSModuleInfo module = CreateModuleInfoForGetModule(resolvedModulePath, refresh);
                            if (module != null)
                            {
                                if (!modules.Contains(resolvedModulePath))
                                {
                                    modules.Add(resolvedModulePath);
                                    yield return module;
                                }
                            }
                        }
                        else
                        {
                            // Given path is a directory, we first check if it is end with module version.
                            Version version;
                            if (Version.TryParse(moduleName, out version))
                            {
                                moduleName = Path.GetFileName(Directory.GetParent(resolvedModulePath).Name);
                            }

                            var availableModuleFiles = all
                                ? ModuleUtils.GetAllAvailableModuleFiles(resolvedModulePath)
                                : ModuleUtils.GetModuleVersionsFromAbsolutePath(resolvedModulePath);

                            bool foundModule = false;
                            foreach (string file in availableModuleFiles)
                            {
                                PSModuleInfo module = CreateModuleInfoForGetModule(file, refresh);
                                if (module != null)
                                {
                                    if (String.Equals(moduleName, module.Name, StringComparison.OrdinalIgnoreCase))
                                    {
                                        foundModule = true;
                                        // We need to list all versions of the module.
                                        string subModulePath = Path.GetDirectoryName(file);
                                        if (!modules.Contains(subModulePath))
                                        {
                                            modules.Add(subModulePath);
                                            yield return module;
                                        }
                                    }
                                }
                            }

                            // Write error only if Name has no wild cards
                            if (!foundModule && !containsWildCards)
                            {
                                WriteError(CreateModuleNotFoundError(resolvedModulePath));
                            }
                        }
                    }
                }
                else
                {
                    if (!containsWildCards)
                    {
                        WriteError(CreateModuleNotFoundError(modulePath));
                    }
                }