Add Reset-PSResourceRepository cmdlet to recover from corrupted repository store

src/Microsoft.PowerShell.PSResourceGet.psd1

@@ -23,6 +23,7 @@
         'Get-PSScriptFileInfo',
         'Install-PSResource',
         'Register-PSResourceRepository',
+        'Reset-PSResourceRepository',
         'Save-PSResource',
         'Set-PSResourceRepository',
         'New-PSScriptFileInfo',

src/code/RepositorySettings.cs

@@ -72,7 +72,7 @@ public static void CheckRepositoryStore()
             }
             catch (Exception e)
             {
-                throw new PSInvalidOperationException(string.Format(CultureInfo.InvariantCulture, "Repository store may be corrupted, file reading failed with error: {0}.", e.Message));
+                throw new PSInvalidOperationException(string.Format(CultureInfo.InvariantCulture, "Repository store may be corrupted, file reading failed with error: {0}. Try running 'Reset-PSResourceRepository' to reset the repository store.", e.Message));
             }
         }
 
@@ -845,6 +845,116 @@ public static List<PSRepositoryInfo> Read(string[] repoNames, out string[] error
             return reposToReturn.ToList();
         }
 
+        /// <summary>
+        /// Reset the repository store by creating a new PSRepositories.xml file with PSGallery registered.
+        /// This creates a temporary new file first, and only replaces the old file if creation succeeds.
+        /// If creation fails, the old file is restored.
+        /// Returns: PSRepositoryInfo for the PSGallery repository
+        /// </summary>
+        public static PSRepositoryInfo Reset(out string errorMsg)
+        {
+            errorMsg = string.Empty;
+            string tempFilePath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString() + ".xml");
+            string backupFilePath = string.Empty;
+
+            try
+            {
+                // Ensure the repository directory exists
+                if (!Directory.Exists(RepositoryPath))
+                {
+                    Directory.CreateDirectory(RepositoryPath);
+                }
+
+                // Create new repository XML in a temporary location
+                XDocument newRepoXML = new XDocument(
+                    new XElement("configuration"));
+                newRepoXML.Save(tempFilePath);
+
+                // Validate that the temporary file can be loaded
+                try
+                {
+                    LoadXDocument(tempFilePath);
+                }
+                catch (Exception loadEx)
+                {
+                    // Clean up temp file on validation failure
+                    if (File.Exists(tempFilePath))
+                    {
+                        try
+                        {
+                            File.Delete(tempFilePath);
+                        }
+                        catch (Exception cleanupEx)
+                        {
+                            errorMsg = string.Format(CultureInfo.InvariantCulture, "Failed to validate newly created repository store file with error: {0}. Additionally, cleanup of temporary file failed with error: {1}", loadEx.Message, cleanupEx.Message);
+                            return null;
+                        }
+                    }
+                    errorMsg = string.Format(CultureInfo.InvariantCulture, "Failed to validate newly created repository store file with error: {0}.", loadEx.Message);
+                    return null;
+                }
+
+                // Back up the existing file if it exists
+                if (File.Exists(FullRepositoryPath))
+                {
+                    backupFilePath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString() + "_backup.xml");
+                    Utils.MoveFiles(FullRepositoryPath, backupFilePath, overwrite: true);
+                }
+
+                // Move the temporary file to the actual location
+                Utils.MoveFiles(tempFilePath, FullRepositoryPath, overwrite: true);
+
+                // Add PSGallery to the newly created store
+                Uri psGalleryUri = new Uri(PSGalleryRepoUri);
+                PSRepositoryInfo psGalleryRepo = Add(PSGalleryRepoName, psGalleryUri, DefaultPriority, DefaultTrusted, repoCredentialInfo: null, repoCredentialProvider: CredentialProviderType.None, APIVersion.V2, force: false);
+
+                // Clean up backup file on success
+                if (!string.IsNullOrEmpty(backupFilePath) && File.Exists(backupFilePath))
+                {
+                    File.Delete(backupFilePath);
+                }
+
+                return psGalleryRepo;
+            }
+            catch (Exception e)
+            {
+                // Restore the backup file if it exists
+                if (!string.IsNullOrEmpty(backupFilePath) && File.Exists(backupFilePath))
+                {
+                    try
+                    {
+                        if (File.Exists(FullRepositoryPath))
+                        {
+                            File.Delete(FullRepositoryPath);
+                        }
+                        Utils.MoveFiles(backupFilePath, FullRepositoryPath, overwrite: true);
+                    }
+                    catch (Exception restoreEx)
+                    {
+                        errorMsg = string.Format(CultureInfo.InvariantCulture, "Repository store reset failed with error: {0}. An attempt to restore the old repository store also failed with error: {1}", e.Message, restoreEx.Message);
+                        return null;
+                    }
+                }
+
+                // Clean up temporary file
+                if (File.Exists(tempFilePath))
+                {
+                    try
+                    {
+                        File.Delete(tempFilePath);
+                    }
+                    catch (Exception cleanupEx)
+                    {
+                        errorMsg = string.Format(CultureInfo.InvariantCulture, "Repository store reset failed with error: {0}. Additionally, cleanup of temporary file failed with error: {1}", e.Message, cleanupEx.Message);
+                        return null;
+                    }
+                }
+
+                errorMsg = string.Format(CultureInfo.InvariantCulture, "Repository store reset failed with error: {0}.", e.Message);
+                return null;
+            }
+        }
+
         #endregion
 
         #region Private methods

src/code/ResetPSResourceRepository.cs

@@ -0,0 +1,70 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using Microsoft.PowerShell.PSResourceGet.UtilClasses;
+using System;
+using System.Management.Automation;
+
+namespace Microsoft.PowerShell.PSResourceGet.Cmdlets
+{
+    /// <summary>
+    /// The Reset-PSResourceRepository cmdlet resets the repository store by creating a new PSRepositories.xml file.
+    /// This is useful when the repository store becomes corrupted.
+    /// It will create a new repository store with only the PSGallery repository registered.
+    /// </summary>
+    [Cmdlet(VerbsCommon.Reset,
+        "PSResourceRepository",
+        SupportsShouldProcess = true,
+        ConfirmImpact = ConfirmImpact.High)]
+    [OutputType(typeof(PSRepositoryInfo))]
+    public sealed class ResetPSResourceRepository : PSCmdlet
+    {
+        #region Parameters
+
+        /// <summary>
+        /// When specified, displays the PSGallery repository that was registered after reset
+        /// </summary>
+        [Parameter]
+        public SwitchParameter PassThru { get; set; }
+
+        #endregion
+
+        #region Methods
+
+        protected override void ProcessRecord()
+        {
+            string repositoryStorePath = System.IO.Path.Combine(
+                Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+                "PSResourceGet",
+                "PSResourceRepository.xml");
+
+            WriteVerbose($"Resetting repository store at: {repositoryStorePath}");
+
+            if (!ShouldProcess(repositoryStorePath, "Reset repository store and create new PSRepositories.xml file with PSGallery registered"))
+            {
+                return;
+            }
+
+            PSRepositoryInfo psGalleryRepo = RepositorySettings.Reset(out string errorMsg);
+
+            if (!string.IsNullOrEmpty(errorMsg))
+            {
+                WriteError(new ErrorRecord(
+                    new PSInvalidOperationException(errorMsg),
+                    "ErrorResettingRepositoryStore",
+                    ErrorCategory.InvalidOperation,
+                    this));
+                return;
+            }
+
+            WriteVerbose("Repository store reset successfully. PSGallery has been registered.");
+
+            if (PassThru)
+            {
+                WriteObject(psGalleryRepo);
+            }
+        }
+
+        #endregion
+    }
+}

test/ResourceRepositoryTests/ResetPSResourceRepository.Tests.ps1

@@ -0,0 +1,149 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+$modPath = "$psscriptroot/../PSGetTestUtils.psm1"
+Write-Verbose -Verbose -Message "PSGetTestUtils path: $modPath"
+Import-Module $modPath -Force -Verbose
+
+Describe "Test Reset-PSResourceRepository" -tags 'CI' {
+    BeforeEach {
+        $PSGalleryName = Get-PSGalleryName
+        $PSGalleryUri = Get-PSGalleryLocation
+        Get-NewPSResourceRepositoryFile
+    }
+
+    AfterEach {
+        Get-RevertPSResourceRepositoryFile
+    }
+
+    It "Reset repository store without PassThru parameter" {
+        # Arrange: Add a test repository
+        $TestRepoName = "testRepository"
+        $tmpDirPath = Join-Path -Path $TestDrive -ChildPath "tmpDir1"
+        New-Item -ItemType Directory -Path $tmpDirPath -Force | Out-Null
+        Register-PSResourceRepository -Name $TestRepoName -Uri $tmpDirPath
+
+        # Verify repository was added
+        $repos = Get-PSResourceRepository
+        $repos.Count | Should -BeGreaterThan 1
+
+        # Act: Reset repository store
+        Reset-PSResourceRepository -Confirm:$false
+
+        # Assert: Only PSGallery should exist
+        $repos = Get-PSResourceRepository
+        $repos.Count | Should -Be 1
+        $repos.Name | Should -Be $PSGalleryName
+        $repos.Uri | Should -Be $PSGalleryUri
+    }
+
+    It "Reset repository store with PassThru parameter returns PSGallery" {
+        # Arrange: Add a test repository
+        $TestRepoName = "testRepository"
+        $tmpDirPath = Join-Path -Path $TestDrive -ChildPath "tmpDir1"
+        New-Item -ItemType Directory -Path $tmpDirPath -Force | Out-Null
+        Register-PSResourceRepository -Name $TestRepoName -Uri $tmpDirPath
+
+        # Act: Reset repository store with PassThru
+        $result = Reset-PSResourceRepository -Confirm:$false -PassThru
+
+        # Assert: Result should be PSGallery repository info
+        $result | Should -Not -BeNullOrEmpty
+        $result.Name | Should -Be $PSGalleryName
+        $result.Uri | Should -Be $PSGalleryUri
+        $result.Trusted | Should -Be $false
+        $result.Priority | Should -Be 50
+
+        # Verify only PSGallery exists
+        $repos = Get-PSResourceRepository
+        $repos.Count | Should -Be 1
+    }
+
+    It "Reset repository store should support -WhatIf" {
+        # Arrange: Add a test repository
+        $TestRepoName = "testRepository"
+        $tmpDirPath = Join-Path -Path $TestDrive -ChildPath "tmpDir1"
+        New-Item -ItemType Directory -Path $tmpDirPath -Force | Out-Null
+        Register-PSResourceRepository -Name $TestRepoName -Uri $tmpDirPath
+
+        # Capture repository count before WhatIf
+        $reposBefore = Get-PSResourceRepository
+        $countBefore = $reposBefore.Count
+
+        # Act: Run with WhatIf
+        Reset-PSResourceRepository -WhatIf
+
+        # Assert: Repositories should not have changed
+        $reposAfter = Get-PSResourceRepository
+        $reposAfter.Count | Should -Be $countBefore
+    }
+
+    It "Reset repository store when corrupted should succeed" {
+        # Arrange: Corrupt the repository file
+        $powerShellGetPath = Join-Path -Path ([Environment]::GetFolderPath([System.Environment+SpecialFolder]::LocalApplicationData)) -ChildPath "PSResourceGet"
+        $repoFilePath = Join-Path -Path $powerShellGetPath -ChildPath "PSResourceRepository.xml"
+
+        # Write invalid XML to corrupt the file
+        "This is not valid XML" | Set-Content -Path $repoFilePath -Force
+
+        # Act: Reset the repository store
+        $result = Reset-PSResourceRepository -Confirm:$false -PassThru
+
+        # Assert: Should successfully reset and return PSGallery
+        $result | Should -Not -BeNullOrEmpty
+        $result.Name | Should -Be $PSGalleryName
+
+        # Verify we can now read repositories
+        $repos = Get-PSResourceRepository
+        $repos.Count | Should -Be 1
+        $repos.Name | Should -Be $PSGalleryName
+    }
+
+    It "Reset repository store when file doesn't exist should succeed" {
+        # Arrange: Delete the repository file
+        $powerShellGetPath = Join-Path -Path ([Environment]::GetFolderPath([System.Environment+SpecialFolder]::LocalApplicationData)) -ChildPath "PSResourceGet"
+        $repoFilePath = Join-Path -Path $powerShellGetPath -ChildPath "PSResourceRepository.xml"
+
+        if (Test-Path -Path $repoFilePath) {
+            Remove-Item -Path $repoFilePath -Force
+        }
+
+        # Act: Reset the repository store
+        $result = Reset-PSResourceRepository -Confirm:$false -PassThru
+
+        # Assert: Should successfully reset and return PSGallery
+        $result | Should -Not -BeNullOrEmpty
+        $result.Name | Should -Be $PSGalleryName
+
+        # Verify PSGallery is registered
+        $repos = Get-PSResourceRepository
+        $repos.Count | Should -Be 1
+        $repos.Name | Should -Be $PSGalleryName
+    }
+
+    It "Reset repository store with multiple repositories should only keep PSGallery" {
+        # Arrange: Register multiple repositories
+        $tmpDir1Path = Join-Path -Path $TestDrive -ChildPath "tmpDir1"
+        $tmpDir2Path = Join-Path -Path $TestDrive -ChildPath "tmpDir2"
+        $tmpDir3Path = Join-Path -Path $TestDrive -ChildPath "tmpDir3"
+        New-Item -ItemType Directory -Path $tmpDir1Path -Force | Out-Null
+        New-Item -ItemType Directory -Path $tmpDir2Path -Force | Out-Null
+        New-Item -ItemType Directory -Path $tmpDir3Path -Force | Out-Null
+
+        Register-PSResourceRepository -Name "testRepo1" -Uri $tmpDir1Path
+        Register-PSResourceRepository -Name "testRepo2" -Uri $tmpDir2Path
+        Register-PSResourceRepository -Name "testRepo3" -Uri $tmpDir3Path
+
+        # Verify multiple repositories exist
+        $reposBefore = Get-PSResourceRepository
+        $reposBefore.Count | Should -BeGreaterThan 1
+
+        # Act: Reset repository store
+        Reset-PSResourceRepository -Confirm:$false
+
+        # Assert: Only PSGallery should remain
+        $reposAfter = Get-PSResourceRepository
+        $reposAfter.Count | Should -Be 1
+        $reposAfter.Name | Should -Be $PSGalleryName
+    }
+}