16 files changed, 653 insertions, 201 deletions

diff --git a/src/wix/WixToolset.Core.WindowsInstaller/Bind/BindTransformCommand.cs b/src/wix/WixToolset.Core.WindowsInstaller/Bind/BindTransformCommand.cs
index 3379ec5d..3d8e7595 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/Bind/BindTransformCommand.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/Bind/BindTransformCommand.cs
@@ -62,18 +62,19 @@ namespace WixToolset.Core.WindowsInstaller.Bind
 
             if (this.Transform.TryGetTable("Property", out var propertyTable))
             {
-                for (int i = propertyTable.Rows.Count - 1; i >= 0; i--)
+                for (var i = propertyTable.Rows.Count - 1; i >= 0; i--)
                 {
-                    Row row = propertyTable.Rows[i];
+                    var row = propertyTable.Rows[i];
+                    var id = row.FieldAsString(0);
 
-                    if ("ProductCode" == (string)row[0] || "ProductLanguage" == (string)row[0] || "ProductVersion" == (string)row[0] || "UpgradeCode" == (string)row[0])
+                    if ("ProductCode" == id || "ProductLanguage" == id || "ProductVersion" == id)
                     {
                         propertyTable.Rows.RemoveAt(i);
-
-                        if ("UpgradeCode" == (string)row[0])
-                        {
-                            updatedUpgradeCode = (string)row[1];
-                        }
+                    }
+                    else if ("UpgradeCode" == id)
+                    {
+                        updatedUpgradeCode = id;
+                        propertyTable.Rows.RemoveAt(i);
                     }
                 }
             }
@@ -383,11 +384,6 @@ namespace WixToolset.Core.WindowsInstaller.Bind
                 }
             }
 
-            //foreach (BinderExtension extension in this.Extensions)
-            //{
-            //    extension.PostBind(this.Context);
-            //}
-
             // Any errors encountered up to this point can cause errors during generation.
             if (this.Messaging.EncounteredError)
             {
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/Bind/LoadTableDefinitionsCommand.cs b/src/wix/WixToolset.Core.WindowsInstaller/Bind/LoadTableDefinitionsCommand.cs
index 2eb95bc5..475a88f9 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/Bind/LoadTableDefinitionsCommand.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/Bind/LoadTableDefinitionsCommand.cs
@@ -2,9 +2,7 @@
 
 namespace WixToolset.Core.WindowsInstaller.Bind
 {
-    using System;
     using System.Collections.Generic;
-    using System.Globalization;
     using System.Linq;
     using WixToolset.Data;
     using WixToolset.Data.Symbols;
@@ -32,9 +30,9 @@ namespace WixToolset.Core.WindowsInstaller.Bind
         public TableDefinitionCollection Execute()
         {
             var tableDefinitions = new TableDefinitionCollection(WindowsInstallerTableDefinitions.All);
-            var customColumnsById = this.Section.Symbols.OfType<WixCustomTableColumnSymbol>().ToDictionary(t => t.Id.Id);
+            var customColumnsById = this.Section?.Symbols.OfType<WixCustomTableColumnSymbol>().ToDictionary(t => t.Id.Id);
 
-            if (customColumnsById.Any())
+            if (customColumnsById?.Any() == true)
             {
                 foreach (var symbol in this.Section.Symbols.OfType<WixCustomTableSymbol>())
                 {
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/CommandLine/TransformSubcommand.cs b/src/wix/WixToolset.Core.WindowsInstaller/CommandLine/TransformSubcommand.cs
new file mode 100644
index 00000000..7ed41d1a
--- /dev/null
+++ b/src/wix/WixToolset.Core.WindowsInstaller/CommandLine/TransformSubcommand.cs
@@ -0,0 +1,352 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolset.Core.WindowsInstaller.CommandLine
+{
+    using System;
+    using System.IO;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using WixToolset.Core.WindowsInstaller.Bind;
+    using WixToolset.Core.WindowsInstaller.Unbind;
+    using WixToolset.Data;
+    using WixToolset.Data.Symbols;
+    using WixToolset.Data.WindowsInstaller;
+    using WixToolset.Extensibility;
+    using WixToolset.Extensibility.Services;
+
+    internal class TransformSubcommand : WindowsInstallerSubcommandBase
+    {
+        public TransformSubcommand(IServiceProvider serviceProvider)
+        {
+            this.Messaging = serviceProvider.GetService<IMessaging>();
+            this.BackendHelper = serviceProvider.GetService<IBackendHelper>();
+            this.ExtensionManager = serviceProvider.GetService<IExtensionManager>();
+        }
+
+        private IMessaging Messaging { get; }
+
+        private IBackendHelper BackendHelper { get; }
+
+        private IExtensionManager ExtensionManager { get; }
+
+        private string OutputPath { get; set; }
+
+        private string TargetPath { get; set; }
+
+        private string UpdatedPath { get; set; }
+
+        private string ExportBasePath { get; set; }
+
+        private string IntermediateFolder { get; set; }
+
+        private bool IsAdminImage { get; set; }
+
+        private bool PreserveUnchangedRows { get; set; }
+
+        private bool ShowPedanticMessages { get; set; }
+
+        private bool SuppressKeepingSpecialRows { get; set; }
+
+        private bool OutputAsWixout { get; set; }
+
+        private TransformFlags ValidationFlags { get; set; }
+
+        public override Task<int> ExecuteAsync(CancellationToken cancellationToken)
+        {
+            if (String.IsNullOrEmpty(this.TargetPath))
+            {
+                Console.Error.WriteLine("Input file required");
+                return Task.FromResult(-1);
+            }
+
+            if (String.IsNullOrEmpty(this.OutputPath))
+            {
+                Console.Error.WriteLine("Output file required");
+                return Task.FromResult(-1);
+            }
+
+            if (String.IsNullOrEmpty(this.IntermediateFolder))
+            {
+                this.IntermediateFolder = Path.GetTempPath();
+            }
+
+            var transform = this.LoadTransform();
+
+            if (!this.Messaging.EncounteredError)
+            {
+                this.SaveTransform(transform);
+            }
+
+            return Task.FromResult(this.Messaging.EncounteredError ? 1 : 0);
+        }
+
+        public override bool TryParseArgument(ICommandLineParser parser, string argument)
+        {
+            if (parser.IsSwitch(argument))
+            {
+                var parameter = argument.Substring(1);
+                switch (parameter.ToLowerInvariant())
+                {
+                    case "a":
+                        this.IsAdminImage = true;
+                        return true;
+
+                    case "intermediatefolder":
+                        this.IntermediateFolder = parser.GetNextArgumentAsDirectoryOrError(argument);
+                        return true;
+
+                    case "o":
+                    case "out":
+                        this.OutputPath = parser.GetNextArgumentAsFilePathOrError(argument);
+                        return true;
+
+                    case "p":
+                        this.PreserveUnchangedRows = true;
+                        return true;
+
+                    case "pedantic":
+                        this.ShowPedanticMessages = true;
+                        return true;
+
+                    case "serr":
+                    {
+                        var serr = parser.GetNextArgumentOrError(argument);
+
+                        switch (serr.ToLowerInvariant())
+                        {
+                            case "a":
+                                this.ValidationFlags |= TransformFlags.ErrorAddExistingRow;
+                                return true;
+
+                            case "b":
+                                this.ValidationFlags |= TransformFlags.ErrorDeleteMissingRow;
+                                return true;
+
+                            case "c":
+                                this.ValidationFlags |= TransformFlags.ErrorAddExistingTable;
+                                return true;
+
+                            case "d":
+                                this.ValidationFlags |= TransformFlags.ErrorDeleteMissingTable;
+                                return true;
+
+                            case "e":
+                                this.ValidationFlags |= TransformFlags.ErrorUpdateMissingRow;
+                                return true;
+
+                            case "f":
+                                this.ValidationFlags |= TransformFlags.ErrorChangeCodePage;
+                                return true;
+
+                            default:
+                                this.Messaging.Write(ErrorMessages.ExpectedArgument(serr));
+                                return true;
+                        }
+                    }
+
+                    case "val":
+                    {
+                        var val = parser.GetNextArgumentOrError(argument);
+
+                        switch (val.ToLowerInvariant())
+                        {
+                            case "language":
+                                this.ValidationFlags |= TransformFlags.LanguageTransformDefault;
+                                return true;
+
+                            case "instance":
+                                this.ValidationFlags |= TransformFlags.InstanceTransformDefault;
+                                return true;
+
+                            case "patch":
+                                this.ValidationFlags |= TransformFlags.PatchTransformDefault;
+                                return true;
+
+                            case "g":
+                                this.ValidationFlags |= TransformFlags.ValidateUpgradeCode;
+                                return true;
+
+                            case "l":
+                                this.ValidationFlags |= TransformFlags.ValidateLanguage;
+                                return true;
+
+                            case "r":
+                                this.ValidationFlags |= TransformFlags.ValidateProduct;
+                                return true;
+
+                            case "s":
+                                this.ValidationFlags |= TransformFlags.ValidateMajorVersion;
+                                return true;
+
+                            case "t":
+                                this.ValidationFlags |= TransformFlags.ValidateMinorVersion;
+                                return true;
+
+                            case "u":
+                                this.ValidationFlags |= TransformFlags.ValidateUpdateVersion;
+                                return true;
+
+                            case "v":
+                                this.ValidationFlags |= TransformFlags.ValidateNewLessBaseVersion;
+                                return true;
+
+                            case "w":
+                                this.ValidationFlags |= TransformFlags.ValidateNewLessEqualBaseVersion;
+                                return true;
+
+                            case "x":
+                                this.ValidationFlags |= TransformFlags.ValidateNewEqualBaseVersion;
+                                return true;
+
+                            case "y":
+                                this.ValidationFlags |= TransformFlags.ValidateNewGreaterEqualBaseVersion;
+                                return true;
+
+                            case "z":
+                                this.ValidationFlags |= TransformFlags.ValidateNewGreaterBaseVersion;
+                                return true;
+
+                            default:
+                                this.Messaging.Write(ErrorMessages.ExpectedArgument(val));
+                                return true;
+                        }
+                    }
+
+                    case "x":
+                        this.ExportBasePath = parser.GetNextArgumentAsDirectoryOrError(argument);
+                        return true;
+
+                    case "xo":
+                        this.OutputAsWixout = true;
+                        return true;
+                }
+            }
+            else if (String.IsNullOrEmpty(this.TargetPath))
+            {
+                this.TargetPath = argument;
+                return true;
+            }
+            else if (String.IsNullOrEmpty(this.UpdatedPath))
+            {
+                this.UpdatedPath = argument;
+                return true;
+            }
+
+            return false;
+        }
+
+        private WindowsInstallerData LoadTransform()
+        {
+            WindowsInstallerData transform;
+
+            if (String.IsNullOrEmpty(this.UpdatedPath))
+            {
+                Exception exception;
+
+                (transform, exception) = LoadWindowsInstallerDataSafely(this.TargetPath);
+
+                if (transform?.Type != OutputType.Transform)
+                {
+                    this.Messaging.Write(WindowsInstallerBackendErrors.CannotLoadWixoutAsTransform(new SourceLineNumber(this.TargetPath), exception));
+                }
+            }
+            else
+            {
+                transform = this.CreateTransform();
+
+                if (null == transform.Tables || 0 >= transform.Tables.Count)
+                {
+                    this.Messaging.Write(ErrorMessages.NoDifferencesInTransform(new SourceLineNumber(this.OutputPath)));
+                }
+            }
+
+            return transform;
+        }
+
+        private void SaveTransform(WindowsInstallerData transform)
+        {
+            if (this.OutputAsWixout)
+            {
+                using (var output = WixOutput.Create(this.OutputPath))
+                {
+                    transform.Save(output);
+                }
+            }
+            else
+            {
+                var fileSystemExtensions = this.ExtensionManager.GetServices<IFileSystemExtension>();
+                var fileSystemManager = new FileSystemManager(fileSystemExtensions);
+
+                var tableDefinitions = this.GetTableDefinitions();
+
+                var bindCommand = new BindTransformCommand(this.Messaging, this.BackendHelper, fileSystemManager, this.IntermediateFolder, transform, this.OutputPath, tableDefinitions);
+                bindCommand.Execute();
+            }
+        }
+
+        private WindowsInstallerData CreateTransform()
+        {
+            if (!TryLoadWindowsInstallerData(this.TargetPath, out var targetOutput))
+            {
+                var unbindCommand = new UnbindMsiOrMsmCommand(this.Messaging, this.BackendHelper, this.TargetPath, this.ExportBasePath, this.IntermediateFolder, this.IsAdminImage, suppressDemodularization: true, suppressExtractCabinets: true);
+                targetOutput = unbindCommand.Execute();
+            }
+
+            if (!TryLoadWindowsInstallerData(this.TargetPath, out var updatedOutput))
+            {
+                var unbindCommand = new UnbindMsiOrMsmCommand(this.Messaging, this.BackendHelper, this.UpdatedPath, this.ExportBasePath, this.IntermediateFolder, this.IsAdminImage, suppressDemodularization: true, suppressExtractCabinets: true);
+                updatedOutput = unbindCommand.Execute();
+            }
+
+            var differ = new Differ(this.Messaging)
+            {
+                PreserveUnchangedRows = this.PreserveUnchangedRows,
+                ShowPedanticMessages = this.ShowPedanticMessages,
+                SuppressKeepingSpecialRows = this.SuppressKeepingSpecialRows
+            };
+
+            return differ.Diff(targetOutput, updatedOutput, this.ValidationFlags);
+        }
+
+        private TableDefinitionCollection GetTableDefinitions()
+        {
+            var backendExtensions = this.ExtensionManager.GetServices<IWindowsInstallerBackendBinderExtension>();
+
+            var loadTableDefinitions = new LoadTableDefinitionsCommand(this.Messaging, null, backendExtensions);
+            return loadTableDefinitions.Execute();
+        }
+
+        private static bool TryLoadWindowsInstallerData(string path, out WindowsInstallerData data)
+        {
+            data = null;
+
+            var extension = Path.GetExtension(path);
+
+            // If the path is _not_ obviously a Windows Installer database, let's try opening it as
+            // our own data file format.
+            if (!extension.Equals(".msi", StringComparison.OrdinalIgnoreCase) && !extension.Equals(".msm", StringComparison.OrdinalIgnoreCase))
+            {
+                (data, _) = LoadWindowsInstallerDataSafely(path);
+            }
+
+            return data != null;
+        }
+
+        private static (WindowsInstallerData, Exception) LoadWindowsInstallerDataSafely(string path)
+        {
+            WindowsInstallerData data = null;
+            Exception exception = null;
+
+            try
+            {
+                data = WindowsInstallerData.Load(path);
+            }
+            catch (Exception e)
+            {
+                exception = e;
+            }
+
+            return (data, exception);
+        }
+    }
+}
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/CommandLine/WindowsInstallerCommand.cs b/src/wix/WixToolset.Core.WindowsInstaller/CommandLine/WindowsInstallerCommand.cs
index a0da7fa4..ed0c0658 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/CommandLine/WindowsInstallerCommand.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/CommandLine/WindowsInstallerCommand.cs
@@ -49,6 +49,10 @@ namespace WixToolset.Core.WindowsInstaller.CommandLine
                         this.Subcommand = new InscribeSubcommand(this.ServiceProvider);
                         return true;
 
+                    case "transform":
+                        this.Subcommand = new TransformSubcommand(this.ServiceProvider);
+                        return true;
+
                     case "validate":
                         this.Subcommand = new ValidateSubcommand(this.ServiceProvider);
                         return true;
@@ -72,6 +76,7 @@ namespace WixToolset.Core.WindowsInstaller.CommandLine
             Console.WriteLine("Commands:");
             Console.WriteLine();
             Console.WriteLine("  inscribe          Updates MSI database with cabinet signature information.");
+            Console.WriteLine("  transform         Creates an MST transform file.");
             Console.WriteLine("  validate          Validates MSI database using standard or custom ICEs.");
         }
     }
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/Differ.cs b/src/wix/WixToolset.Core.WindowsInstaller/Differ.cs
index 304d0152..8b474605 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/Differ.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/Differ.cs
@@ -1,18 +1,15 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
-#if DELETE
-
 namespace WixToolset.Core.WindowsInstaller
 {
     using System;
     using System.Collections;
     using System.Collections.Generic;
     using System.Globalization;
-    using WixToolset.Core.WindowsInstaller.Msi;
+    using WixToolset.Core.Native.Msi;
     using WixToolset.Data;
     using WixToolset.Data.Symbols;
     using WixToolset.Data.WindowsInstaller;
-    using WixToolset.Data.WindowsInstaller.Rows;
     using WixToolset.Extensibility;
     using WixToolset.Extensibility.Services;
 
@@ -22,9 +19,6 @@ namespace WixToolset.Core.WindowsInstaller
     public sealed class Differ
     {
         private readonly List<IInspectorExtension> inspectorExtensions;
-        private bool showPedanticMessages;
-        private bool suppressKeepingSpecialRows;
-        private bool preserveUnchangedRows;
         private const char sectionDelimiter = '/';
         private readonly IMessaging messaging;
         private SummaryInformationStreams transformSummaryInfo;
@@ -42,31 +36,19 @@ namespace WixToolset.Core.WindowsInstaller
         /// Gets or sets the option to show pedantic messages.
         /// </summary>
         /// <value>The option to show pedantic messages.</value>
-        public bool ShowPedanticMessages
-        {
-            get { return this.showPedanticMessages; }
-            set { this.showPedanticMessages = value; }
-        }
+        public bool ShowPedanticMessages { get; set; }
 
         /// <summary>
         /// Gets or sets the option to suppress keeping special rows.
         /// </summary>
         /// <value>The option to suppress keeping special rows.</value>
-        public bool SuppressKeepingSpecialRows
-        {
-            get { return this.suppressKeepingSpecialRows; }
-            set { this.suppressKeepingSpecialRows = value; }
-        }
+        public bool SuppressKeepingSpecialRows { get; set; }
 
         /// <summary>
         /// Gets or sets the flag to determine if all rows, even unchanged ones will be persisted in the output.
         /// </summary>
         /// <value>The option to keep all rows including unchanged rows.</value>
-        public bool PreserveUnchangedRows
-        {
-            get { return this.preserveUnchangedRows; }
-            set { this.preserveUnchangedRows = value; }
-        }
+        public bool PreserveUnchangedRows { get; set; }
 
         /// <summary>
         /// Adds an extension.
@@ -97,7 +79,7 @@ namespace WixToolset.Core.WindowsInstaller
         /// <returns>The transform.</returns>
         public WindowsInstallerData Diff(WindowsInstallerData targetOutput, WindowsInstallerData updatedOutput, TransformFlags validationFlags)
         {
-            WindowsInstallerData transform = new WindowsInstallerData(null);
+            var transform = new WindowsInstallerData(null);
             transform.Type = OutputType.Transform;
             transform.Codepage = updatedOutput.Codepage;
             this.transformSummaryInfo = new SummaryInformationStreams();
@@ -119,34 +101,34 @@ namespace WixToolset.Core.WindowsInstaller
             }
 
             // compare the contents of the tables
-            foreach (Table targetTable in targetOutput.Tables)
+            foreach (var targetTable in targetOutput.Tables)
             {
-                Table updatedTable = updatedOutput.Tables[targetTable.Name];
-                TableOperation operation = TableOperation.None;
+                var updatedTable = updatedOutput.Tables[targetTable.Name];
+                var operation = TableOperation.None;
 
-                List<Row> rows = this.CompareTables(targetOutput, targetTable, updatedTable, out operation);
+                var rows = this.CompareTables(targetOutput, targetTable, updatedTable, out operation);
 
                 if (TableOperation.Drop == operation)
                 {
-                    Table droppedTable = transform.EnsureTable(targetTable.Definition);
+                    var droppedTable = transform.EnsureTable(targetTable.Definition);
                     droppedTable.Operation = TableOperation.Drop;
                 }
                 else if (TableOperation.None == operation)
                 {
-                    Table modified = transform.EnsureTable(updatedTable.Definition);
+                    var modified = transform.EnsureTable(updatedTable.Definition);
                     rows.ForEach(r => modified.Rows.Add(r));
                 }
             }
 
             // added tables
-            foreach (Table updatedTable in updatedOutput.Tables)
+            foreach (var updatedTable in updatedOutput.Tables)
             {
                 if (null == targetOutput.Tables[updatedTable.Name])
                 {
-                    Table addedTable = transform.EnsureTable(updatedTable.Definition);
+                    var addedTable = transform.EnsureTable(updatedTable.Definition);
                     addedTable.Operation = TableOperation.Add;
 
-                    foreach (Row updatedRow in updatedTable.Rows)
+                    foreach (var updatedRow in updatedTable.Rows)
                     {
                         updatedRow.Operation = RowOperation.Add;
                         updatedRow.SectionId = sectionDelimiter + updatedRow.SectionId;
@@ -156,9 +138,9 @@ namespace WixToolset.Core.WindowsInstaller
             }
 
             // set summary information properties
-            if (!this.suppressKeepingSpecialRows)
+            if (!this.SuppressKeepingSpecialRows)
             {
-                Table summaryInfoTable = transform.Tables["_SummaryInformation"];
+                var summaryInfoTable = transform.Tables["_SummaryInformation"];
                 this.UpdateTransformSummaryInformationTable(summaryInfoTable, validationFlags);
             }
 
@@ -170,53 +152,56 @@ namespace WixToolset.Core.WindowsInstaller
         /// </summary>
         /// <param name="index">The indexed rows.</param>
         /// <param name="row">The row to index.</param>
-        private void AddIndexedRow(IDictionary index, Row row)
+        private void AddIndexedRow(IDictionary<string, Row> index, Row row)
         {
-            string primaryKey = row.GetPrimaryKey('/');
-            if (null != primaryKey)
+            var primaryKey = row.GetPrimaryKey('/');
+
+            // If there is no primary, use the string representation of the row as its
+            // primary key (even though it may not be unique).
+            if (String.IsNullOrEmpty(primaryKey))
             {
-                // Overriding WixActionRows have a primary key defined and take precedence in the index.
-                if (row is WixActionRow)
+                // This is provided for compatibility with unreal tables with no primary key
+                // all real tables must specify at least one column as the primary key.
+                primaryKey = row.ToString();
+                index[primaryKey] = row;
+            }
+            else
+            {
+                if (!index.TryGetValue(primaryKey, out var existingRow))
+                {
+                    index.Add(primaryKey, row);
+                }
+                else
                 {
-                    WixActionRow currentRow = (WixActionRow)row;
-                    if (index.Contains(primaryKey))
+#if TODO
+                    // Overriding WixActionRows have a primary key defined and take precedence in the index.
+                    if (row is WixActionRow currentActionRow)
                     {
                         // If the current row is not overridable, see if the indexed row is.
-                        if (!currentRow.Overridable)
+                        if (!currentActionRow.Overridable)
                         {
-                            WixActionRow indexedRow = index[primaryKey] as WixActionRow;
-                            if (null != indexedRow && indexedRow.Overridable)
+                            if (existingRow is WixActionRow existingActionRow && existingActionRow.Overridable)
                             {
                                 // The indexed key is overridable and should be replaced
                                 // (not removed and re-added which results in two Array.Copy
                                 // operations for SortedList, or may be re-hashing in other
                                 // implementations of IDictionary).
-                                index[primaryKey] = currentRow;
+                                index[primaryKey] = currentActionRow;
                             }
                         }
 
                         // If we got this far, the row does not need to be indexed.
                         return;
                     }
-                }
+#endif
 
-                // Nothing else should be added more than once.
-                if (!index.Contains(primaryKey))
-                {
-                    index.Add(primaryKey, row);
-                }
-                else if (this.showPedanticMessages)
-                {
-                    this.messaging.Write(ErrorMessages.DuplicatePrimaryKey(row.SourceLineNumbers, primaryKey, row.Table.Name));
+                    // Nothing else should be added more than once.
+                    if (this.ShowPedanticMessages)
+                    {
+                        this.messaging.Write(ErrorMessages.DuplicatePrimaryKey(row.SourceLineNumbers, primaryKey, row.Table.Name));
+                    }
                 }
             }
-            else // use the string representation of the row as its primary key (it may not be unique)
-            {
-                // this is provided for compatibility with unreal tables with no primary key
-                // all real tables must specify at least one column as the primary key
-                primaryKey = row.ToString();
-                index[primaryKey] = row;
-            }
         }
 
         private Row CompareRows(Table targetTable, Row targetRow, Row updatedRow, out RowOperation operation, out bool keepRow)
@@ -235,7 +220,7 @@ namespace WixToolset.Core.WindowsInstaller
                 else if (null == updatedRow)
                 {
                     operation = targetRow.Operation = RowOperation.Delete;
-                    targetRow.SectionId = targetRow.SectionId + sectionDelimiter;
+                    targetRow.SectionId += sectionDelimiter;
                     comparedRow = targetRow;
                     keepRow = true;
                 }
@@ -243,7 +228,7 @@ namespace WixToolset.Core.WindowsInstaller
             else // possibly modified
             {
                 updatedRow.Operation = RowOperation.None;
-                if (!this.suppressKeepingSpecialRows && "_SummaryInformation" == targetTable.Name)
+                if (!this.SuppressKeepingSpecialRows && "_SummaryInformation" == targetTable.Name)
                 {
                     // ignore rows that shouldn't be in a transform
                     if (Enum.IsDefined(typeof(SummaryInformation.Transform), (int)updatedRow[0]))
@@ -256,18 +241,18 @@ namespace WixToolset.Core.WindowsInstaller
                 }
                 else
                 {
-                    if (this.preserveUnchangedRows)
+                    if (this.PreserveUnchangedRows)
                     {
                         keepRow = true;
                     }
 
-                    for (int i = 0; i < updatedRow.Fields.Length; i++)
+                    for (var i = 0; i < updatedRow.Fields.Length; i++)
                     {
-                        ColumnDefinition columnDefinition = updatedRow.Fields[i].Column;
+                        var columnDefinition = updatedRow.Fields[i].Column;
 
                         if (!columnDefinition.PrimaryKey)
                         {
-                            bool modified = false;
+                            var modified = false;
 
                             if (i >= targetRow.Fields.Length)
                             {
@@ -290,12 +275,12 @@ namespace WixToolset.Core.WindowsInstaller
                                 updatedRow.Fields[i].PreviousData = (string)targetRow.Fields[i].Data;
 
                                 // keep rows containing preserved fields so the historical data is available to the binder
-                                keepRow = !this.suppressKeepingSpecialRows;
+                                keepRow = !this.SuppressKeepingSpecialRows;
                             }
                             else if (ColumnType.Object == columnDefinition.Type)
                             {
-                                ObjectField targetObjectField = (ObjectField)targetRow.Fields[i];
-                                ObjectField updatedObjectField = (ObjectField)updatedRow.Fields[i];
+                                var targetObjectField = (ObjectField)targetRow.Fields[i];
+                                var updatedObjectField = (ObjectField)updatedRow.Fields[i];
 
                                 updatedObjectField.PreviousEmbeddedFileIndex = targetObjectField.EmbeddedFileIndex;
                                 updatedObjectField.PreviousBaseUri = targetObjectField.BaseUri;
@@ -308,7 +293,7 @@ namespace WixToolset.Core.WindowsInstaller
                                 updatedObjectField.UnresolvedPreviousData = (string)targetObjectField.UnresolvedData;
 
                                 // keep rows containing object fields so the files can be compared in the binder
-                                keepRow = !this.suppressKeepingSpecialRows;
+                                keepRow = !this.SuppressKeepingSpecialRows;
                             }
                             else
                             {
@@ -342,7 +327,7 @@ namespace WixToolset.Core.WindowsInstaller
 
         private List<Row> CompareTables(WindowsInstallerData targetOutput, Table targetTable, Table updatedTable, out TableOperation operation)
         {
-            List<Row> rows = new List<Row>();
+            var rows = new List<Row>();
             operation = TableOperation.None;
 
             // dropped tables
@@ -360,8 +345,8 @@ namespace WixToolset.Core.WindowsInstaller
             }
             else // possibly modified tables
             {
-                SortedList updatedPrimaryKeys = new SortedList();
-                SortedList targetPrimaryKeys = new SortedList();
+                var updatedPrimaryKeys = new SortedDictionary<string, Row>();
+                var targetPrimaryKeys = new SortedDictionary<string, Row>();
 
                 // compare the table definitions
                 if (0 != targetTable.Definition.CompareTo(updatedTable.Definition))
@@ -374,13 +359,10 @@ namespace WixToolset.Core.WindowsInstaller
                     this.IndexPrimaryKeys(targetTable, targetPrimaryKeys, updatedTable, updatedPrimaryKeys);
 
                     // diff the target and updated rows
-                    foreach (DictionaryEntry targetPrimaryKeyEntry in targetPrimaryKeys)
+                    foreach (var targetPrimaryKeyEntry in targetPrimaryKeys)
                     {
-                        string targetPrimaryKey = (string)targetPrimaryKeyEntry.Key;
-                        bool keepRow = false;
-                        RowOperation rowOperation = RowOperation.None;
-
-                        Row compared = this.CompareRows(targetTable, targetPrimaryKeyEntry.Value as Row, updatedPrimaryKeys[targetPrimaryKey] as Row, out rowOperation, out keepRow);
+                        var targetPrimaryKey = targetPrimaryKeyEntry.Key;
+                        var compared = this.CompareRows(targetTable, targetPrimaryKeyEntry.Value, updatedPrimaryKeys[targetPrimaryKey], out var _, out var keepRow);
 
                         if (keepRow)
                         {
@@ -389,13 +371,13 @@ namespace WixToolset.Core.WindowsInstaller
                     }
 
                     // find the inserted rows
-                    foreach (DictionaryEntry updatedPrimaryKeyEntry in updatedPrimaryKeys)
+                    foreach (var updatedPrimaryKeyEntry in updatedPrimaryKeys)
                     {
-                        string updatedPrimaryKey = (string)updatedPrimaryKeyEntry.Key;
+                        var updatedPrimaryKey = (string)updatedPrimaryKeyEntry.Key;
 
-                        if (!targetPrimaryKeys.Contains(updatedPrimaryKey))
+                        if (!targetPrimaryKeys.ContainsKey(updatedPrimaryKey))
                         {
-                            Row updatedRow = (Row)updatedPrimaryKeyEntry.Value;
+                            var updatedRow = (Row)updatedPrimaryKeyEntry.Value;
 
                             updatedRow.Operation = RowOperation.Add;
                             updatedRow.SectionId = sectionDelimiter + updatedRow.SectionId;
@@ -408,10 +390,10 @@ namespace WixToolset.Core.WindowsInstaller
             return rows;
         }
 
-        private void IndexPrimaryKeys(Table targetTable, SortedList targetPrimaryKeys, Table updatedTable, SortedList updatedPrimaryKeys)
+        private void IndexPrimaryKeys(Table targetTable, SortedDictionary<string, Row> targetPrimaryKeys, Table updatedTable, SortedDictionary<string, Row> updatedPrimaryKeys)
         {
             // index the target rows
-            foreach (Row row in targetTable.Rows)
+            foreach (var row in targetTable.Rows)
             {
                 this.AddIndexedRow(targetPrimaryKeys, row);
 
@@ -452,7 +434,7 @@ namespace WixToolset.Core.WindowsInstaller
             }
 
             // index the updated rows
-            foreach (Row row in updatedTable.Rows)
+            foreach (var row in updatedTable.Rows)
             {
                 this.AddIndexedRow(updatedPrimaryKeys, row);
 
@@ -492,17 +474,15 @@ namespace WixToolset.Core.WindowsInstaller
         private void UpdateTransformSummaryInformationTable(Table summaryInfoTable, TransformFlags validationFlags)
         {
             // calculate the minimum version of MSI required to process the transform
-            int targetMin;
-            int updatedMin;
-            int minimumVersion = 100;
+            var minimumVersion = 100;
 
-            if (Int32.TryParse(this.transformSummaryInfo.TargetMinimumVersion, out targetMin) && Int32.TryParse(this.transformSummaryInfo.UpdatedMinimumVersion, out updatedMin))
+            if (Int32.TryParse(this.transformSummaryInfo.TargetMinimumVersion, out var targetMin) && Int32.TryParse(this.transformSummaryInfo.UpdatedMinimumVersion, out var updatedMin))
             {
                 minimumVersion = Math.Max(targetMin, updatedMin);
             }
 
-            Hashtable summaryRows = new Hashtable(summaryInfoTable.Rows.Count);
-            foreach (Row row in summaryInfoTable.Rows)
+            var summaryRows = new Hashtable(summaryInfoTable.Rows.Count);
+            foreach (var row in summaryInfoTable.Rows)
             {
                 summaryRows[row[0]] = row;
 
@@ -535,35 +515,35 @@ namespace WixToolset.Core.WindowsInstaller
 
             if (!summaryRows.Contains((int)SummaryInformation.Transform.TargetPlatformAndLanguage))
             {
-                Row summaryRow = summaryInfoTable.CreateRow(null);
+                var summaryRow = summaryInfoTable.CreateRow(null);
                 summaryRow[0] = (int)SummaryInformation.Transform.TargetPlatformAndLanguage;
                 summaryRow[1] = this.transformSummaryInfo.TargetPlatformAndLanguage;
             }
 
             if (!summaryRows.Contains((int)SummaryInformation.Transform.UpdatedPlatformAndLanguage))
             {
-                Row summaryRow = summaryInfoTable.CreateRow(null);
+                var summaryRow = summaryInfoTable.CreateRow(null);
                 summaryRow[0] = (int)SummaryInformation.Transform.UpdatedPlatformAndLanguage;
                 summaryRow[1] = this.transformSummaryInfo.UpdatedPlatformAndLanguage;
             }
 
             if (!summaryRows.Contains((int)SummaryInformation.Transform.ValidationFlags))
             {
-                Row summaryRow = summaryInfoTable.CreateRow(null);
+                var summaryRow = summaryInfoTable.CreateRow(null);
                 summaryRow[0] = (int)SummaryInformation.Transform.ValidationFlags;
                 summaryRow[1] = ((int)validationFlags).ToString(CultureInfo.InvariantCulture);
             }
 
             if (!summaryRows.Contains((int)SummaryInformation.Transform.InstallerRequirement))
             {
-                Row summaryRow = summaryInfoTable.CreateRow(null);
+                var summaryRow = summaryInfoTable.CreateRow(null);
                 summaryRow[0] = (int)SummaryInformation.Transform.InstallerRequirement;
                 summaryRow[1] = minimumVersion.ToString(CultureInfo.InvariantCulture);
             }
 
             if (!summaryRows.Contains((int)SummaryInformation.Transform.Security))
             {
-                Row summaryRow = summaryInfoTable.CreateRow(null);
+                var summaryRow = summaryInfoTable.CreateRow(null);
                 summaryRow[0] = (int)SummaryInformation.Transform.Security;
                 summaryRow[1] = "4";
             }
@@ -606,5 +586,3 @@ namespace WixToolset.Core.WindowsInstaller
         }
     }
 }
-
-#endif
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/MsiBackend.cs b/src/wix/WixToolset.Core.WindowsInstaller/MsiBackend.cs
index 33aa7a74..628ad8de 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/MsiBackend.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/MsiBackend.cs
@@ -2,6 +2,7 @@
 
 namespace WixToolset.Core.WindowsInstaller
 {
+    using System;
     using WixToolset.Core.WindowsInstaller.Bind;
     using WixToolset.Core.WindowsInstaller.Decompile;
     using WixToolset.Core.WindowsInstaller.Unbind;
@@ -71,8 +72,7 @@ namespace WixToolset.Core.WindowsInstaller
 
         public Intermediate Unbind(IUnbindContext context)
         {
-            var command = new UnbindMsiOrMsmCommand(context);
-            return command.Execute();
+            throw new NotImplementedException();
         }
     }
 }
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/MsmBackend.cs b/src/wix/WixToolset.Core.WindowsInstaller/MsmBackend.cs
index 02ea5f45..01e3c6d8 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/MsmBackend.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/MsmBackend.cs
@@ -2,6 +2,7 @@
 
 namespace WixToolset.Core.WindowsInstaller
 {
+    using System;
     using WixToolset.Core.WindowsInstaller.Bind;
     using WixToolset.Core.WindowsInstaller.Decompile;
     using WixToolset.Core.WindowsInstaller.Unbind;
@@ -67,8 +68,7 @@ namespace WixToolset.Core.WindowsInstaller
 
         public Intermediate Unbind(IUnbindContext context)
         {
-            var command = new UnbindMsiOrMsmCommand(context);
-            return command.Execute();
+            throw new NotImplementedException();
         }
     }
 }
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/MspBackend.cs b/src/wix/WixToolset.Core.WindowsInstaller/MspBackend.cs
index d1f5eb99..398fc780 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/MspBackend.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/MspBackend.cs
@@ -4,13 +4,7 @@ namespace WixToolset.Core.WindowsInstaller
 {
     using System;
     using System.Collections.Generic;
-    using System.IO;
-    using System.Linq;
     using WixToolset.Core.WindowsInstaller.Bind;
-    using WixToolset.Core.Native.Msi;
-    using WixToolset.Core.WindowsInstaller.Unbind;
-    using WixToolset.Data;
-    using WixToolset.Data.Symbols;
     using WixToolset.Data.WindowsInstaller;
     using WixToolset.Extensibility;
     using WixToolset.Extensibility.Data;
@@ -74,9 +68,9 @@ namespace WixToolset.Core.WindowsInstaller
             throw new NotImplementedException();
         }
 
+#if TODO_PATCHING
         public Intermediate Unbind(IUnbindContext context)
         {
-#if TODO_PATCHING
             Output patch;
 
             // patch files are essentially database files (use a special flag to let the API know its a patch file)
@@ -156,8 +150,7 @@ namespace WixToolset.Core.WindowsInstaller
             }
 
             return patch;
-#endif
-            throw new NotImplementedException();
         }
+#endif
     }
 }
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/MstBackend.cs b/src/wix/WixToolset.Core.WindowsInstaller/MstBackend.cs
deleted file mode 100644
index 8ce75265..00000000
--- a/src/wix/WixToolset.Core.WindowsInstaller/MstBackend.cs
+++ /dev/null
@@ -1,39 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-namespace WixToolset.Core.WindowsInstaller
-{
-    using System;
-    using WixToolset.Core.WindowsInstaller.Unbind;
-    using WixToolset.Data;
-    using WixToolset.Extensibility;
-    using WixToolset.Extensibility.Data;
-
-    internal class MstBackend : IBackend
-    {
-        public IBindResult Bind(IBindContext context)
-        {
-#if TODO_PATCHING
-            var command = new BindTransformCommand();
-            command.Extensions = context.Extensions;
-            command.TempFilesLocation = context.IntermediateFolder;
-            command.Transform = context.IntermediateRepresentation;
-            command.OutputPath = context.OutputPath;
-            command.Execute();
-
-            return new BindResult(Array.Empty<FileTransfer>(), Array.Empty<string>());
-#endif
-            throw new NotImplementedException();
-        }
-
-        public IDecompileResult Decompile(IDecompileContext context)
-        {
-            throw new NotImplementedException();
-        }
-
-        public Intermediate Unbind(IUnbindContext context)
-        {
-            var command = new UnbindMsiOrMsmCommand(context);
-            return command.Execute();
-        }
-    }
-}
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindMsiOrMsmCommand.cs b/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindMsiOrMsmCommand.cs
index 75ee6307..82015cf2 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindMsiOrMsmCommand.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindMsiOrMsmCommand.cs
@@ -4,52 +4,80 @@ namespace WixToolset.Core.WindowsInstaller.Unbind
 {
     using System;
     using System.ComponentModel;
+    using WixToolset.Core.Native.Msi;
     using WixToolset.Data;
+    using WixToolset.Data.WindowsInstaller;
     using WixToolset.Extensibility.Data;
-    using WixToolset.Core.Native.Msi;
+    using WixToolset.Extensibility.Services;
 
     internal class UnbindMsiOrMsmCommand
     {
+        public UnbindMsiOrMsmCommand(IMessaging messaging, IBackendHelper backendHelper, string databasePath, string exportBasePath, string intermediateFolder, bool adminImage, bool suppressDemodularization, bool suppressExtractCabinets)
+        {
+            this.Messaging = messaging;
+            this.BackendHelper = backendHelper;
+            this.DatabasePath = databasePath;
+            this.ExportBasePath = exportBasePath;
+            this.IntermediateFolder = intermediateFolder;
+            this.IsAdminImage = adminImage;
+            this.SuppressDemodularization = suppressDemodularization;
+            this.SuppressExtractCabinets = suppressExtractCabinets;
+        }
+
         public UnbindMsiOrMsmCommand(IUnbindContext context)
         {
-            this.Context = context;
+            this.Messaging = context.ServiceProvider.GetService<IMessaging>();
+            this.DatabasePath = context.InputFilePath;
+            this.ExportBasePath = context.ExportBasePath;
+            this.IntermediateFolder = context.IntermediateFolder;
+            this.IsAdminImage = context.IsAdminImage;
+            this.SuppressDemodularization = context.SuppressDemodularization;
         }
 
-        public IUnbindContext Context { get; }
+        private IMessaging Messaging { get; }
 
-        public Intermediate Execute()
-        {
-#if TODO_PATCHING
-            Output output;
+        private IBackendHelper BackendHelper { get; }
+
+        private string DatabasePath { get; }
+
+        private string ExportBasePath { get; }
 
+        private string IntermediateFolder { get; }
+
+        private bool IsAdminImage { get; }
+
+        private bool SuppressDemodularization { get; }
+
+        private bool SuppressExtractCabinets { get; }
+
+        public WindowsInstallerData Execute()
+        {
             try
             {
-                using (Database database = new Database(this.Context.InputFilePath, OpenDatabase.ReadOnly))
+                using (var database = new Database(this.DatabasePath, OpenDatabase.ReadOnly))
                 {
-                    var unbindCommand = new UnbindDatabaseCommand(this.Context.Messaging, database, this.Context.InputFilePath, OutputType.Product, this.Context.ExportBasePath, this.Context.IntermediateFolder, this.Context.IsAdminImage, this.Context.SuppressDemodularization, skipSummaryInfo: false);
-                    output = unbindCommand.Execute();
+                    var unbindCommand = new UnbindDatabaseCommand(this.Messaging, this.BackendHelper, database, this.DatabasePath, OutputType.Product, this.ExportBasePath, this.IntermediateFolder, this.IsAdminImage, this.SuppressDemodularization, skipSummaryInfo: false);
+                    var data = unbindCommand.Execute();
 
                     // extract the files from the cabinets
-                    if (!String.IsNullOrEmpty(this.Context.ExportBasePath) && !this.Context.SuppressExtractCabinets)
+                    if (!String.IsNullOrEmpty(this.ExportBasePath) && !this.SuppressExtractCabinets)
                     {
-                        var extractCommand = new ExtractCabinetsCommand(output, database, this.Context.InputFilePath, this.Context.ExportBasePath, this.Context.IntermediateFolder);
+                        var extractCommand = new ExtractCabinetsCommand(data, database, this.DatabasePath, this.ExportBasePath, this.IntermediateFolder);
                         extractCommand.Execute();
                     }
+
+                    return data;
                 }
             }
             catch (Win32Exception e)
             {
                 if (0x6E == e.NativeErrorCode) // ERROR_OPEN_FAILED
                 {
-                    throw new WixException(WixErrors.OpenDatabaseFailed(this.Context.InputFilePath));
+                    //throw new WixException(WixErrors.OpenDatabaseFailed(this.DatabasePath));
                 }
 
                 throw;
             }
-
-            return output;
-#endif
-            throw new NotImplementedException();
         }
     }
 }
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindTranformCommand.cs b/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindTransformCommand.cs
index f40aed4e..ea40fa9f 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindTranformCommand.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/Unbind/UnbindTransformCommand.cs
@@ -41,7 +41,7 @@ namespace WixToolset.Core.WindowsInstaller.Unbind
         private TableDefinitionCollection TableDefinitions { get; }
 
         private string EmptyFile { get; set; }
-        
+
         public WindowsInstallerData Execute()
         {
             var transform = new WindowsInstallerData(new SourceLineNumber(this.TransformFile));
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendErrors.cs b/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendErrors.cs
index 0c15ad05..2efb06f1 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendErrors.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendErrors.cs
@@ -2,14 +2,17 @@
 
 namespace WixToolset.Core.WindowsInstaller
 {
+    using System;
     using WixToolset.Data;
 
     internal static class WindowsInstallerBackendErrors
     {
-        //public static Message ReplaceThisWithTheFirstError(SourceLineNumber sourceLineNumbers)
-        //{
-        //    return Message(sourceLineNumbers, Ids.ReplaceThisWithTheFirstError, "format string", arg1, arg2);
-        //}
+        public static Message CannotLoadWixoutAsTransform(SourceLineNumber sourceLineNumbers, Exception exception)
+        {
+            var additionalDetail = exception == null ? String.Empty : ", detail: " + exception.Message;
+
+            return Message(sourceLineNumbers, Ids.CannotLoadWixoutAsTransform, "Could not load wixout file as a transform{1}", additionalDetail);
+        }
 
         private static Message Message(SourceLineNumber sourceLineNumber, Ids id, string format, params object[] args)
         {
@@ -18,7 +21,7 @@ namespace WixToolset.Core.WindowsInstaller
 
         public enum Ids
         {
-            // ReplaceThisWithTheFirstError = 7500,
+            CannotLoadWixoutAsTransform = 7500,
         } // last available is 7999. 8000 is BurnBackendErrors.
     }
 }
diff --git a/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendFactory.cs b/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendFactory.cs
index f72acb21..d14743e9 100644
--- a/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendFactory.cs
+++ b/src/wix/WixToolset.Core.WindowsInstaller/WindowsInstallerBackendFactory.cs
@@ -37,11 +37,6 @@ namespace WixToolset.Core.WindowsInstaller
                 //case "patchcreation":
                 //case ".pcp":
                 //    return new PatchCreationBackend();
-
-                case "transform":
-                case ".mst":
-                    backend = new MstBackend();
-                    return true;
             }
 
             backend = null;
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.en-us.wxl b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.en-us.wxl
index f7453566..d3844e39 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.en-us.wxl
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.en-us.wxl
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <WixLocalization xmlns="http://wixtoolset.org/schemas/v4/wxl" Culture="en-US">
 
-  <String Id="DowngradeError">A newer version of [ProductName] is already installed.</String>
-  <String Id="FeatureTitle">MsiPackage</String>
+  <String Id="DowngradeError">A newer version en-us of [ProductName] is already installed.</String>
+  <String Id="FeatureTitle">MsiPackage en-us</String>
 
 </WixLocalization>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.ja-jp.wxl b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.ja-jp.wxl
index ef287da7..48a339d3 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.ja-jp.wxl
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Language/Package.ja-jp.wxl
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <WixLocalization xmlns="http://wixtoolset.org/schemas/v4/wxl" Culture="ja-JP">
 
-  <String Id="DowngradeError">A newer version of [ProductName] is already installed.</String>
-  <String Id="FeatureTitle">MsiPackage</String>
+  <String Id="DowngradeError">A newer version ja-jp of [ProductName] is already installed.</String>
+  <String Id="FeatureTitle">MsiPackage ja-jp</String>
 
 </WixLocalization>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TransformFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/TransformFixture.cs
new file mode 100644
index 00000000..bdbf5c26
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TransformFixture.cs
@@ -0,0 +1,143 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolsetTest.CoreIntegration
+{
+    using System.IO;
+    using System.Linq;
+    using WixBuildTools.TestSupport;
+    using WixToolset.Core.TestPackage;
+    using WixToolset.Data.WindowsInstaller;
+    using Xunit;
+
+    public class TransformFixture
+    {
+        [Fact]
+        public void CanBuildTransformFromEnuToJpn()
+        {
+            var folder = TestData.Get(@"TestData", "Language");
+
+            using (var fs = new DisposableFileSystem())
+            {
+                var baseFolder = fs.GetFolder();
+                var enuMsiPath = Path.Combine(baseFolder, @"bin\enu.msi");
+                var jpnMsiPath = Path.Combine(baseFolder, @"bin\jpn.msi");
+                var mstPath = Path.Combine(baseFolder, @"bin\test.mst");
+
+                var result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, "Package.wxs"),
+                    "-loc", Path.Combine(folder, "Package.en-us.wxl"),
+                    "-bindpath", Path.Combine(folder, "data"),
+                    "-intermediateFolder", Path.Combine(baseFolder, "obj"),
+                    "-o", enuMsiPath
+                });
+                result.AssertSuccess();
+
+
+                result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, "Package.wxs"),
+                    "-loc", Path.Combine(folder, "Package.ja-jp.wxl"),
+                    "-bindpath", Path.Combine(folder, "data"),
+                    "-intermediateFolder", Path.Combine(baseFolder, "obj"),
+                    "-o", jpnMsiPath
+                });
+                result.AssertSuccess();
+
+                result = WixRunner.Execute(new[]
+                {
+                    "msi", "transform",
+                    "-intermediateFolder", Path.Combine(baseFolder, "obj"),
+                    "-serr", "f",
+                    "-o", mstPath,
+                    enuMsiPath,
+                    jpnMsiPath
+                });
+                result.AssertSuccess();
+
+                Assert.True(File.Exists(mstPath));
+            }
+        }
+
+        [Fact]
+        public void CanBuildWixoutTransform()
+        {
+            var folder = TestData.Get(@"TestData", "Language");
+
+            using (var fs = new DisposableFileSystem())
+            {
+                var baseFolder = fs.GetFolder();
+                var enuMsiPath = Path.Combine(baseFolder, @"bin\enu.msi");
+                var jpnMsiPath = Path.Combine(baseFolder, @"bin\jpn.msi");
+                var wixmstPath = Path.Combine(baseFolder, @"bin\test.wixmst");
+                var mstPath = Path.Combine(baseFolder, @"bin\test.mst");
+
+                var result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, "Package.wxs"),
+                    "-loc", Path.Combine(folder, "Package.en-us.wxl"),
+                    "-bindpath", Path.Combine(folder, "data"),
+                    "-intermediateFolder", Path.Combine(baseFolder, "obj"),
+                    "-o", enuMsiPath
+                });
+                result.AssertSuccess();
+
+                result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, "Package.wxs"),
+                    "-loc", Path.Combine(folder, "Package.ja-jp.wxl"),
+                    "-bindpath", Path.Combine(folder, "data"),
+                    "-intermediateFolder", Path.Combine(baseFolder, "obj"),
+                    "-o", jpnMsiPath
+                });
+                result.AssertSuccess();
+
+                result = WixRunner.Execute(new[]
+                {
+                    "msi", "transform",
+                    "-intermediateFolder", Path.Combine(baseFolder, "obj"),
+                    "-serr", "f",
+                    "-xo",
+                    "-o", wixmstPath,
+                    enuMsiPath,
+                    jpnMsiPath
+                });
+                result.AssertSuccess();
+
+                var wixmst = WindowsInstallerData.Load(wixmstPath);
+                var rows = wixmst.Tables.SelectMany(t => t.Rows).Where(r => r.Operation == RowOperation.Modify).ToDictionary(r => r.GetPrimaryKey());
+
+                WixAssert.CompareLineByLine(new[]
+                {
+                    "NOT WIX_DOWNGRADE_DETECTED",
+                    "ProductCode",
+                    "ProductFeature",
+                    "ProductLanguage"
+                }, rows.Keys.OrderBy(s => s).ToArray());
+
+                Assert.True(rows.TryGetValue("ProductFeature", out var productFeatureRow));
+                Assert.Equal("MsiPackage ja-jp", productFeatureRow.FieldAsString(2));
+
+                Assert.True(rows.TryGetValue("ProductLanguage", out var productLanguageRow));
+                Assert.Equal("1041", productLanguageRow.FieldAsString(1));
+
+                Assert.False(File.Exists(mstPath));
+
+                result = WixRunner.Execute(new[]
+                {
+                    "msi", "transform",
+                    "-intermediateFolder", Path.Combine(baseFolder, "obj"),
+                    "-o", mstPath,
+                    wixmstPath
+                });
+                result.AssertSuccess();
+
+                Assert.True(File.Exists(mstPath));
+            }
+        }
+    }
+}