Rework build command line for combining wixlibs and default output

Changes the command line handling for the "build" command to allow
creation of a .wixlib to accept compiled (but not linked)
intermediates. This will allow .wixlibs to combine separate build
commands (potentially with different "-arch" switches) into a single
.wixlib. This change also fixes the issue where by default output
was being written to the intermediate folder instead of the current
directory.

Fixes 6464
Fixes 6473

6 files changed, 277 insertions, 125 deletions

diff --git a/src/wix/WixToolset.Core/CommandLine/BuildCommand.cs b/src/wix/WixToolset.Core/CommandLine/BuildCommand.cs
index 67d2876d..f291fa8c 100644
--- a/src/wix/WixToolset.Core/CommandLine/BuildCommand.cs
+++ b/src/wix/WixToolset.Core/CommandLine/BuildCommand.cs
@@ -49,18 +49,8 @@ namespace WixToolset.Core.CommandLine
 
         private string IntermediateFolder { get; set; }
 
-        private OutputType OutputType { get; set; }
-
-        private List<string> IncludeSearchPaths { get; set; }
-
-        public string PdbFile { get; set; }
-
-        public PdbType PdbType { get; set; }
-
         private Platform Platform { get; set; }
 
-        private string OutputFile { get; set; }
-
         private CompressionLevel? DefaultCompressionLevel { get; set; }
 
         private string TrackingFile { get; set; }
@@ -75,93 +65,70 @@ namespace WixToolset.Core.CommandLine
 
             this.IntermediateFolder = this.commandLine.CalculateIntermedateFolder();
 
-            this.OutputType = this.commandLine.CalculateOutputType();
-
-            this.IncludeSearchPaths = this.commandLine.IncludeSearchPaths;
-
-            this.PdbFile = this.commandLine.PdbFile;
-
-            this.PdbType = this.commandLine.PdbType;
-
             this.Platform = this.commandLine.Platform;
 
             this.TrackingFile = this.commandLine.TrackingFile;
 
             this.DefaultCompressionLevel = this.commandLine.DefaultCompressionLevel;
 
-            var preprocessorVariables = this.commandLine.GatherPreprocessorVariables();
-
-            var sourceFiles = this.commandLine.GatherSourceFiles(this.IntermediateFolder);
+            var preprocessorVariables = this.commandLine.CalculatePreprocessorVariables();
 
             var filterCultures = this.commandLine.CalculateFilterCultures();
 
             var creator = this.ServiceProvider.GetService<ISymbolDefinitionCreator>();
 
-            this.EvaluateSourceFiles(sourceFiles, creator, out var codeFiles, out var wixipl);
-
-            this.OutputFile = this.commandLine.OutputFile;
-
-            if (String.IsNullOrEmpty(this.OutputFile))
-            {
-                if (codeFiles.Count == 1)
-                {
-                    // If output type is unknown, the extension will be replaced with the right default based on output type.
-                    this.OutputFile = Path.ChangeExtension(codeFiles[0].OutputPath, DefaultExtensionForOutputType(this.OutputType));
-                }
-                else
-                {
-                    this.Messaging.Write(ErrorMessages.MustSpecifyOutputWithMoreThanOneInput());
-                }
-            }
+            var inputsOutputs = this.commandLine.CalculateInputsAndOutputs(creator);
 
             if (this.Messaging.EncounteredError)
             {
                 return Task.FromResult(this.Messaging.LastErrorNumber);
             }
 
-            var wixobjs = this.CompilePhase(preprocessorVariables, codeFiles, cancellationToken);
+            var wixobjs = this.CompilePhase(preprocessorVariables, inputsOutputs.SourcePaths, this.commandLine.IncludeSearchPaths, cancellationToken);
 
-            var wxls = this.LoadLocalizationFiles(this.commandLine.LocalizationFilePaths, preprocessorVariables, cancellationToken);
+            var wxls = this.LoadLocalizationFiles(inputsOutputs.LocalizationPaths, preprocessorVariables, this.commandLine.IncludeSearchPaths, cancellationToken);
 
             if (this.Messaging.EncounteredError)
             {
                 return Task.FromResult(this.Messaging.LastErrorNumber);
             }
 
-            if (this.OutputType == OutputType.Library)
+            if (inputsOutputs.OutputType == OutputType.Library)
             {
                 using (new IntermediateFieldContext("wix.lib"))
                 {
-                    this.LibraryPhase(wixobjs, wxls, this.commandLine.BindFiles, this.commandLine.BindPaths, cancellationToken);
+                    this.LibraryPhase(wixobjs, wxls, inputsOutputs.LibraryPaths, creator, this.commandLine.BindFiles, this.commandLine.BindPaths, inputsOutputs.OutputPath, cancellationToken);
                 }
             }
             else
             {
                 using (new IntermediateFieldContext("wix.link"))
                 {
+                    var wixipl = inputsOutputs.Wixipls.SingleOrDefault();
+
                     if (wixipl == null)
                     {
-                        wixipl = this.LinkPhase(wixobjs, this.commandLine.LibraryFilePaths, creator, cancellationToken);
+                        wixipl = this.LinkPhase(wixobjs, inputsOutputs, creator, cancellationToken);
                     }
 
                     if (!this.Messaging.EncounteredError)
                     {
-                        var outputExtension = Path.GetExtension(this.OutputFile);
+                        var outputExtension = Path.GetExtension(inputsOutputs.OutputPath);
                         if (String.IsNullOrEmpty(outputExtension) || ".wix" == outputExtension)
                         {
                             var entrySectionType = wixipl.Sections.Single().Type;
-                            this.OutputFile = Path.ChangeExtension(this.OutputFile, DefaultExtensionForSectionType(entrySectionType));
+                            inputsOutputs.OutputPath = Path.ChangeExtension(inputsOutputs.OutputPath, DefaultExtensionForSectionType(entrySectionType));
                         }
 
-                        if (this.OutputType == OutputType.IntermediatePostLink)
+                        if (inputsOutputs.OutputType == OutputType.IntermediatePostLink)
                         {
-                            wixipl.Save(this.OutputFile);
+                            wixipl.Save(inputsOutputs.OutputPath);
                         }
                         else
                         {
                             using (new IntermediateFieldContext("wix.bind"))
                             {
-                                this.BindPhase(wixipl, wxls, filterCultures, this.commandLine.CabCachePath, this.commandLine.BindPaths, cancellationToken);
+                                this.BindPhase(wixipl, wxls, filterCultures, this.commandLine.CabCachePath, this.commandLine.BindPaths, inputsOutputs, cancellationToken);
                             }
                         }
                     }
@@ -176,51 +143,13 @@ namespace WixToolset.Core.CommandLine
             return this.commandLine.TryParseArgument(argument, parser);
         }
 
-        private void EvaluateSourceFiles(IEnumerable<SourceFile> sourceFiles, ISymbolDefinitionCreator creator, out List<SourceFile> codeFiles, out Intermediate wixipl)
-        {
-            codeFiles = new List<SourceFile>();
-
-            wixipl = null;
-
-            foreach (var sourceFile in sourceFiles)
-            {
-                var extension = Path.GetExtension(sourceFile.SourcePath);
-
-                if (wixipl != null || ".wxs".Equals(extension, StringComparison.OrdinalIgnoreCase))
-                {
-                    codeFiles.Add(sourceFile);
-                }
-                else
-                {
-                    try
-                    {
-                        wixipl = Intermediate.Load(sourceFile.SourcePath, creator);
-                    }
-                    catch (WixException)
-                    {
-                        // We'll assume anything that isn't a valid intermediate is source code to compile.
-                        codeFiles.Add(sourceFile);
-                    }
-                }
-            }
-
-            if (wixipl == null && codeFiles.Count == 0)
-            {
-                this.Messaging.Write(ErrorMessages.NoSourceFiles());
-            }
-            else if (wixipl != null && codeFiles.Count != 0)
-            {
-                this.Messaging.Write(ErrorMessages.WixiplSourceFileIsExclusive());
-            }
-        }
-
-        private IReadOnlyList<Intermediate> CompilePhase(IDictionary<string, string> preprocessorVariables, IEnumerable<SourceFile> sourceFiles, CancellationToken cancellationToken)
+        private IReadOnlyList<Intermediate> CompilePhase(IDictionary<string, string> preprocessorVariables, IEnumerable<string> sourceFiles, IReadOnlyCollection<string> includeSearchPaths, CancellationToken cancellationToken)
         {
             var intermediates = new List<Intermediate>();
 
             foreach (var sourceFile in sourceFiles)
             {
-                var document = this.Preprocess(preprocessorVariables, sourceFile.SourcePath, cancellationToken);
+                var document = this.Preprocess(preprocessorVariables, sourceFile, includeSearchPaths, cancellationToken);
 
                 if (this.Messaging.EncounteredError)
                 {
@@ -255,14 +184,21 @@ namespace WixToolset.Core.CommandLine
             return intermediates;
         }
 
-        private void LibraryPhase(IReadOnlyCollection<Intermediate> intermediates, IReadOnlyCollection<Localization> localizations, bool bindFiles, IReadOnlyCollection<IBindPath> bindPaths, CancellationToken cancellationToken)
+        private void LibraryPhase(IReadOnlyCollection<Intermediate> intermediates, IReadOnlyCollection<Localization> localizations, IEnumerable<string> libraryFiles, ISymbolDefinitionCreator creator, bool bindFiles, IReadOnlyCollection<IBindPath> bindPaths, string outputPath, CancellationToken cancellationToken)
         {
+            var libraries = this.LoadLibraries(libraryFiles, creator);
+
+            if (this.Messaging.EncounteredError)
+            {
+                return;
+            }
+
             var context = this.ServiceProvider.GetService<ILibraryContext>();
             context.BindFiles = bindFiles;
             context.BindPaths = bindPaths;
             context.Extensions = this.ExtensionManager.GetServices<ILibrarianExtension>();
             context.Localizations = localizations;
-            context.Intermediates = intermediates;
+            context.Intermediates = intermediates.Concat(libraries).ToList();
             context.CancellationToken = cancellationToken;
 
             try
@@ -272,7 +208,7 @@ namespace WixToolset.Core.CommandLine
 
                 if (!this.Messaging.EncounteredError)
                 {
-                    result.Library.Save(this.OutputFile);
+                    result.Library.Save(outputPath);
 
                     this.LayoutFiles(this.IntermediateFolder, result.TrackedFiles, null, cancellationToken);
                 }
@@ -283,9 +219,9 @@ namespace WixToolset.Core.CommandLine
             }
         }
 
-        private Intermediate LinkPhase(IEnumerable<Intermediate> intermediates, IEnumerable<string> libraryFiles, ISymbolDefinitionCreator creator, CancellationToken cancellationToken)
+        private Intermediate LinkPhase(IEnumerable<Intermediate> intermediates, InputsAndOutputs inputsOutputs, ISymbolDefinitionCreator creator, CancellationToken cancellationToken)
         {
-            var libraries = this.LoadLibraries(libraryFiles, creator);
+            var libraries = this.LoadLibraries(inputsOutputs.LibraryPaths, creator);
 
             if (this.Messaging.EncounteredError)
             {
@@ -295,7 +231,7 @@ namespace WixToolset.Core.CommandLine
             var context = this.ServiceProvider.GetService<ILinkContext>();
             context.Extensions = this.ExtensionManager.GetServices<ILinkerExtension>();
             context.ExtensionData = this.ExtensionManager.GetServices<IExtensionData>();
-            context.ExpectedOutputType = this.OutputType;
+            context.ExpectedOutputType = inputsOutputs.OutputType;
             context.Intermediates = intermediates.Concat(libraries).ToList();
             context.SymbolDefinitionCreator = creator;
             context.CancellationToken = cancellationToken;
@@ -304,7 +240,7 @@ namespace WixToolset.Core.CommandLine
             return linker.Link(context);
         }
 
-        private void BindPhase(Intermediate output, IReadOnlyCollection<Localization> localizations, IReadOnlyCollection<string> filterCultures, string cabCachePath, IReadOnlyCollection<IBindPath> bindPaths, CancellationToken cancellationToken)
+        private void BindPhase(Intermediate output, IReadOnlyCollection<Localization> localizations, IReadOnlyCollection<string> filterCultures, string cabCachePath, IReadOnlyCollection<IBindPath> bindPaths, InputsAndOutputs inputsOutputs, CancellationToken cancellationToken)
         {
             var intermediateFolder = this.IntermediateFolder;
             if (String.IsNullOrEmpty(intermediateFolder))
@@ -350,9 +286,9 @@ namespace WixToolset.Core.CommandLine
                     context.FileSystemExtensions = this.ExtensionManager.GetServices<IFileSystemExtension>();
                     context.IntermediateFolder = intermediateFolder;
                     context.IntermediateRepresentation = resolveResult.IntermediateRepresentation;
-                    context.OutputPath = this.OutputFile;
-                    context.PdbType = this.PdbType;
-                    context.PdbPath = this.PdbType == PdbType.None ? null : this.PdbFile ?? Path.ChangeExtension(this.OutputFile, ".wixpdb");
+                    context.OutputPath = inputsOutputs.OutputPath;
+                    context.PdbType = inputsOutputs.PdbType;
+                    context.PdbPath = inputsOutputs.PdbPath;
                     context.CancellationToken = cancellationToken;
 
                     var binder = this.ServiceProvider.GetService<IBinder>();
@@ -405,14 +341,14 @@ namespace WixToolset.Core.CommandLine
             return Array.Empty<Intermediate>();
         }
 
-        private IReadOnlyList<Localization> LoadLocalizationFiles(IEnumerable<string> locFiles, IDictionary<string, string> preprocessorVariables, CancellationToken cancellationToken)
+        private IReadOnlyList<Localization> LoadLocalizationFiles(IEnumerable<string> locFiles, IDictionary<string, string> preprocessorVariables, IReadOnlyCollection<string> includeSearchPaths, CancellationToken cancellationToken)
         {
             var localizations = new List<Localization>();
             var parser = this.ServiceProvider.GetService<ILocalizationParser>();
 
             foreach (var loc in locFiles)
             {
-                var document = this.Preprocess(preprocessorVariables, loc, cancellationToken);
+                var document = this.Preprocess(preprocessorVariables, loc, includeSearchPaths, cancellationToken);
 
                 if (this.Messaging.EncounteredError)
                 {
@@ -426,12 +362,12 @@ namespace WixToolset.Core.CommandLine
             return localizations;
         }
 
-        private XDocument Preprocess(IDictionary<string, string> preprocessorVariables, string sourcePath, CancellationToken cancellationToken)
+        private XDocument Preprocess(IDictionary<string, string> preprocessorVariables, string sourcePath, IReadOnlyCollection<string> includeSearchPaths, CancellationToken cancellationToken)
         {
             var context = this.ServiceProvider.GetService<IPreprocessContext>();
             context.Extensions = this.ExtensionManager.GetServices<IPreprocessorExtension>();
             context.Platform = this.Platform;
-            context.IncludeSearchPaths = this.IncludeSearchPaths;
+            context.IncludeSearchPaths = includeSearchPaths;
             context.SourcePath = sourcePath;
             context.Variables = preprocessorVariables;
             context.CancellationToken = cancellationToken;
@@ -519,6 +455,8 @@ namespace WixToolset.Core.CommandLine
 
             public List<string> SourceFilePaths { get; } = new List<string>();
 
+            public List<string> UnevaluatedInputFilePaths { get; } = new List<string>();
+
             public Platform Platform { get; private set; }
 
             public string PdbFile { get; private set; }
@@ -632,6 +570,10 @@ namespace WixToolset.Core.CommandLine
                             parser.GetNextArgumentAsFilePathOrError(arg, "library files", this.LibraryFilePaths);
                             return true;
 
+                        case "src":
+                            parser.GetNextArgumentAsFilePathOrError(arg, "source code", this.SourceFilePaths);
+                            return true;
+
                         case "o":
                         case "out":
                             this.OutputFile = parser.GetNextArgumentAsFilePathOrError(arg);
@@ -665,7 +607,7 @@ namespace WixToolset.Core.CommandLine
                 }
                 else
                 {
-                    parser.GetArgumentAsFilePathOrError(arg, "source code", this.SourceFilePaths);
+                    parser.GetArgumentAsFilePathOrError(arg, "input file", this.UnevaluatedInputFilePaths);
                     return true;
                 }
             }
@@ -747,7 +689,7 @@ namespace WixToolset.Core.CommandLine
                 return result;
             }
 
-            public IDictionary<string, string> GatherPreprocessorVariables()
+            public IDictionary<string, string> CalculatePreprocessorVariables()
             {
                 var variables = new Dictionary<string, string>();
 
@@ -767,19 +709,89 @@ namespace WixToolset.Core.CommandLine
                 return variables;
             }
 
-            public IEnumerable<SourceFile> GatherSourceFiles(string intermediateDirectory)
+            public InputsAndOutputs CalculateInputsAndOutputs(ISymbolDefinitionCreator creator)
             {
-                var files = new List<SourceFile>();
+                var codePaths = new List<string>(this.SourceFilePaths);
+                var localizationPaths = new List<string>(this.LocalizationFilePaths);
+                var libraryPaths = new List<string>(this.LibraryFilePaths);
+                var wixipls = new List<Intermediate>();
+                string lastWixiplPath = null;
 
-                foreach (var item in this.SourceFilePaths)
+                var outputPath = this.OutputFile;
+                var outputType = this.CalculateOutputType();
+
+                foreach (var path in this.UnevaluatedInputFilePaths)
                 {
-                    var sourcePath = item;
-                    var outputPath = Path.Combine(intermediateDirectory, Path.GetFileNameWithoutExtension(sourcePath) + ".wir");
+                    var extension = Path.GetExtension(path);
+
+                    if (".wxs".Equals(extension, StringComparison.OrdinalIgnoreCase))
+                    {
+                        codePaths.Add(path);
+                    }
+                    else if (".wxl".Equals(extension, StringComparison.OrdinalIgnoreCase))
+                    {
+                        localizationPaths.Add(path);
+                    }
+                    else if (".wixlib".Equals(extension, StringComparison.OrdinalIgnoreCase))
+                    {
+                        libraryPaths.Add(path);
+                    }
+                    else
+                    {
+                        try
+                        {
+                            // Try to load the file as an intermediate to determine whether it is a
+                            // .wixipl or a .wixlib.
+                            var intermediate = Intermediate.Load(path, creator);
 
-                    files.Add(new SourceFile(sourcePath, outputPath));
+                            if (intermediate.HasLevel(IntermediateLevels.Linked))
+                            {
+                                wixipls.Add(intermediate);
+                                lastWixiplPath = path;
+                            }
+                            else
+                            {
+                                libraryPaths.Add(path);
+                            }
+                        }
+                        catch (WixException)
+                        {
+                            // We'll assume anything that isn't a valid intermediate is source code to compile.
+                            codePaths.Add(path);
+                        }
+                    }
                 }
 
-                return files;
+                if (wixipls.Count > 0)
+                {
+                    if (wixipls.Count > 1 || codePaths.Count > 0 || libraryPaths.Count > 0)
+                    {
+                        this.Messaging.Write(ErrorMessages.WixiplSourceFileIsExclusive());
+                    }
+                }
+                else if (codePaths.Count == 0 && libraryPaths.Count == 0)
+                {
+                    this.Messaging.Write(ErrorMessages.NoSourceFiles());
+                }
+
+                if (!this.Messaging.EncounteredError && String.IsNullOrEmpty(outputPath))
+                {
+                    var singleInputPath = codePaths.Count == 1 ? codePaths[0] : lastWixiplPath;
+
+                    if (String.IsNullOrEmpty(singleInputPath))
+                    {
+                        this.Messaging.Write(ErrorMessages.MustSpecifyOutputWithMoreThanOneInput());
+                    }
+                    else
+                    {
+                        // If output type is unknown, the extension will be replaced with the right default based on output type.
+                        outputPath = Path.ChangeExtension(singleInputPath, DefaultExtensionForOutputType(outputType));
+                    }
+                }
+
+                var pdbPath = this.PdbType == PdbType.None ? null : this.PdbFile ?? Path.ChangeExtension(outputPath ?? "error.above", ".wixpdb");
+
+                return new InputsAndOutputs(codePaths, localizationPaths, libraryPaths, wixipls, outputPath, outputType, pdbPath, this.PdbType);
             }
 
             private bool TryParseBindPath(string bindPath, out IBindPath bp)
@@ -807,5 +819,36 @@ namespace WixToolset.Core.CommandLine
                 return true;
             }
         }
+
+        private class InputsAndOutputs
+        {
+            public InputsAndOutputs(IReadOnlyCollection<string> sourcePaths, IReadOnlyCollection<string> localizationPaths, IReadOnlyCollection<string> libraryPaths, IReadOnlyCollection<Intermediate> wixipls, string outputPath, OutputType outputType, string pdbPath, PdbType pdbType)
+            {
+                this.SourcePaths = sourcePaths;
+                this.LocalizationPaths = localizationPaths;
+                this.LibraryPaths = libraryPaths;
+                this.Wixipls = wixipls;
+                this.OutputPath = outputPath;
+                this.OutputType = outputType;
+                this.PdbPath = pdbPath;
+                this.PdbType = pdbType;
+            }
+
+            public IReadOnlyCollection<string> SourcePaths { get; }
+
+            public IReadOnlyCollection<string> LocalizationPaths { get; }
+
+            public IReadOnlyCollection<string> LibraryPaths { get; }
+
+            public IReadOnlyCollection<Intermediate> Wixipls { get; }
+
+            public string OutputPath { get; set; }
+
+            public OutputType OutputType { get; }
+
+            public string PdbPath { get; }
+
+            public PdbType PdbType { get; }
+        }
     }
 }
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs
index 62ffe1eb..f91c0ab0 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs
@@ -6,26 +6,11 @@ namespace WixToolsetTest.CoreIntegration
     using System.IO;
     using WixBuildTools.TestSupport;
     using WixToolset.Core.TestPackage;
-    using WixToolset.Data;
     using Xunit;
 
     public class BadInputFixture
     {
         [Fact]
-        public void SwitchIsNotConsideredAnArgument()
-        {
-            var result = WixRunner.Execute(new[]
-            {
-                "build",
-                "-bindpath", "-thisisaswitchnotanarg",
-            });
-
-            Assert.Single(result.Messages, m => m.Id == (int)ErrorMessages.Ids.ExpectedArgument);
-            // TODO: when CantBuildSingleExeBundleWithInvalidArgument is fixed, uncomment:
-            //Assert.Equal((int)ErrorMessages.Ids.ExpectedArgument, result.ExitCode);
-        }
-
-        [Fact]
         public void HandleInvalidIds()
         {
             var folder = TestData.Get(@"TestData\BadInput");
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/CommandLineFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/CommandLineFixture.cs
new file mode 100644
index 00000000..1b0f9633
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/CommandLineFixture.cs
@@ -0,0 +1,59 @@
+// 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 Xunit;
+
+    public class CommandLineFixture
+    {
+        [Fact]
+        public void SwitchIsNotConsideredAnArgument()
+        {
+            var result = WixRunner.Execute(new[]
+            {
+                "build",
+                "-bindpath", "-thisisaswitchnotanarg",
+            });
+
+            WixAssert.CompareLineByLine(new[]
+            {
+                "-bindpath is expected to be followed by a value. See -? for additional detail.",
+                "Additional argument '-bindpath' was unexpected.  Remove the argument and add the '-?' switch for more information.",
+                "No source files specified."
+            }, result.Messages.Select(m => m.ToString()).ToArray());
+            Assert.Equal(391, result.ExitCode);
+        }
+
+        [Fact]
+        public void CanBuildWithNoOutputSpecified()
+        {
+            var folder = TestData.Get(@"TestData", "SimplePackage");
+            var bindFolder = TestData.Get(@"TestData", "SingleFile", "data");
+
+            using (var fs = new DisposableFileSystem())
+            {
+                var testFolder = fs.GetFolder(create: true);
+                var srcFile = Path.Combine(testFolder, "SimplePackage.wxs");
+                var intermediateFolder = Path.Combine(testFolder, "obj");
+                var expectedPath = Path.Combine(testFolder, "SimplePackage.msi");
+
+                // Copy the source folder into the test working folder so the output can be written to the same folder.
+                File.Copy(Path.Combine(folder, "SimplePackage.wxs"), srcFile);
+
+                var result = WixRunner.Execute(new[]
+                {
+                    "build", srcFile,
+                    "-bindpath", bindFolder,
+                    "-intermediateFolder", intermediateFolder
+                });
+
+                result.AssertSuccess();
+                Assert.True(File.Exists(expectedPath), $"Expected to build MSI to: {expectedPath}");
+            }
+        }
+    }
+}
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/SimplePackage/SimplePackage.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/SimplePackage/SimplePackage.wxs
new file mode 100644
index 00000000..0325867c
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/SimplePackage/SimplePackage.wxs
@@ -0,0 +1,11 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <Feature Id="ProductFeature">
+      <Component Directory="ProgramFilesFolder" Subdirectory="MsiPackage">
+        <File Source="test.txt" />
+      </Component>
+    </Feature>
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/WixlibMultiarch/MultiarchFile.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/WixlibMultiarch/MultiarchFile.wxs
new file mode 100644
index 00000000..c74bf370
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/WixlibMultiarch/MultiarchFile.wxs
@@ -0,0 +1,11 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Fragment>
+    <Directory Id="ProgramFiles3264Folder">
+      <Directory Id="INSTALLFOLDER" Name="Foo">
+        <Component>
+          <File Source="test.txt" />
+        </Component>
+      </Directory>
+    </Directory>
+  </Fragment>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/WixlibFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/WixlibFixture.cs
index 00b83de8..01b82eb3 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/WixlibFixture.cs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/WixlibFixture.cs
@@ -53,6 +53,49 @@ namespace WixToolsetTest.CoreIntegration
         }
 
         [Fact]
+        public void CanBuildMultiarchWixlib()
+        {
+            var folder = TestData.Get(@"TestData", "WixlibMultiarch");
+
+            using (var fs = new DisposableFileSystem())
+            {
+                var baseFolder = fs.GetFolder();
+                var intermediateFolder = Path.Combine(baseFolder, "obj");
+                var wixlibPath = Path.Combine(intermediateFolder, @"test.wixlib");
+
+                var result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, "MultiarchFile.wxs"),
+                    "-intermediateFolder", intermediateFolder,
+                    "-o", wixlibPath
+                });
+
+                result.AssertSuccess();
+
+                result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    "-arch", "x64",
+                    Path.Combine(folder, "MultiarchFile.wxs"),
+                    wixlibPath,
+                    "-intermediateFolder", intermediateFolder,
+                    "-o", wixlibPath
+                });
+
+                result.AssertSuccess();
+
+                var wixlib = Intermediate.Load(wixlibPath);
+                var componentSymbols = wixlib.Sections.SelectMany(s => s.Symbols).OfType<ComponentSymbol>().ToList();
+                WixAssert.CompareLineByLine(new[]
+                {
+                    "x64 filcV1yrx0x8wJWj4qMzcH21jwkPko",
+                    "x86 filcV1yrx0x8wJWj4qMzcH21jwkPko",
+                }, componentSymbols.Select(c => (c.Win64 ? "x64 " : "x86 ") + c.Id.Id).OrderBy(s => s).ToArray());
+            }
+        }
+
+        [Fact]
         public void CanBuildWixlibWithBinariesFromNamedBindPaths()
         {
             var folder = TestData.Get(@"TestData\WixlibWithBinaries");