Support tuples from extensions and make SourcePath a path instead of string

12 files changed, 352 insertions, 76 deletions

diff --git a/src/Directory.Build.props b/src/Directory.Build.props
index 25cb6d36..7cd6767f 100644
--- a/src/Directory.Build.props
+++ b/src/Directory.Build.props
@@ -5,11 +5,13 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <BaseIntermediateOutputPath>$(MSBuildThisFileDirectory)..\build\obj\$(MSBuildProjectName)\</BaseIntermediateOutputPath>
-    <OutputPath>$(MSBuildThisFileDirectory)..\build\$(Configuration)\</OutputPath>
+    <BaseOutputPath>$(MSBuildThisFileDirectory)..\build\$(Configuration)\</BaseOutputPath>
+    <OutputPath>$(BaseOutputPath)</OutputPath>
 
     <Authors>WiX Toolset Team</Authors>
     <Company>WiX Toolset</Company>
     <Copyright>Copyright (c) .NET Foundation and contributors. All rights reserved.</Copyright>
+    <Product>WiX Toolset</Product>
   </PropertyGroup>
 
   <PropertyGroup>
diff --git a/src/WixToolset.Data/DictionaryExtensions.cs b/src/WixToolset.Data/DictionaryExtensions.cs
new file mode 100644
index 00000000..cb6647ff
--- /dev/null
+++ b/src/WixToolset.Data/DictionaryExtensions.cs
@@ -0,0 +1,14 @@
+// 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.Data
+{
+    using System.Collections.Generic;
+
+    internal static class DictionaryExtensions
+    {
+        public static V GetValueOrDefault<K, V>(this IDictionary<K, V> dictionary, K key, V defaultValue = default(V))
+        {
+            return dictionary.TryGetValue(key, out var value) ? value : defaultValue;
+        }
+    }
+}
diff --git a/src/WixToolset.Data/ITupleDefinitionCreator.cs b/src/WixToolset.Data/ITupleDefinitionCreator.cs
index 63477314..7d818be1 100644
--- a/src/WixToolset.Data/ITupleDefinitionCreator.cs
+++ b/src/WixToolset.Data/ITupleDefinitionCreator.cs
@@ -4,6 +4,8 @@ namespace WixToolset.Data
 {
     public interface ITupleDefinitionCreator
     {
+        void AddCustomTupleDefinition(IntermediateTupleDefinition definition);
+
         bool TryGetTupleDefinitionByName(string name, out IntermediateTupleDefinition tupleDefinition);
     }
 }
diff --git a/src/WixToolset.Data/Intermediate.cs b/src/WixToolset.Data/Intermediate.cs
index b03492ce..4d4e17cc 100644
--- a/src/WixToolset.Data/Intermediate.cs
+++ b/src/WixToolset.Data/Intermediate.cs
@@ -4,6 +4,7 @@ namespace WixToolset.Data
 {
     using System;
     using System.Collections.Generic;
+    using System.Linq;
     using System.IO;
     using SimpleJson;
 
@@ -96,8 +97,23 @@ namespace WixToolset.Data
         /// <returns>Returns the loaded intermediate.</returns>
         public static Intermediate Load(string path, bool suppressVersionCheck = false)
         {
+            using (var stream = File.OpenRead(path))
+            {
+                var creator = new SimpleTupleDefinitionCreator();
+                return Intermediate.Load(stream, path, creator, suppressVersionCheck);
+            }
+        }
+
+        /// <summary>
+        /// Loads an intermediate from a stream.
+        /// </summary>
+        /// <param name="stream">Stream to intermediate file.</param>
+        /// <param name="suppressVersionCheck">Suppress checking for wix.dll version mismatches.</param>
+        /// <returns>Returns the loaded intermediate.</returns>
+        public static Intermediate Load(Stream stream, bool suppressVersionCheck = false)
+        {
             var creator = new SimpleTupleDefinitionCreator();
-            return Intermediate.Load(path, creator, suppressVersionCheck);
+            return Intermediate.Load(stream, creator, suppressVersionCheck);
         }
 
         /// <summary>
@@ -109,51 +125,22 @@ namespace WixToolset.Data
         /// <returns>Returns the loaded intermediate.</returns>
         public static Intermediate Load(string path, ITupleDefinitionCreator creator, bool suppressVersionCheck = false)
         {
-            JsonObject jsonObject;
-
-            using (FileStream stream = File.OpenRead(path))
-            using (FileStructure fs = FileStructure.Read(stream))
-            {
-                if (FileFormat.WixIR != fs.FileFormat)
-                {
-                    throw new WixUnexpectedFileFormatException(path, FileFormat.WixIR, fs.FileFormat);
-                }
-
-                var json = fs.GetData();
-                jsonObject = SimpleJson.DeserializeObject(json) as JsonObject;
-            }
-
-            if (!suppressVersionCheck)
+            using (var stream = File.OpenRead(path))
             {
-                var versionJson = jsonObject.GetValueOrDefault<string>("version");
-
-                if (!Version.TryParse(versionJson, out var version) || !Intermediate.CurrentVersion.Equals(version))
-                {
-                    throw new WixException(WixDataErrors.VersionMismatch(SourceLineNumber.CreateFromUri(path), "intermediate", versionJson, Intermediate.CurrentVersion.ToString()));
-                }
+                return Intermediate.Load(stream, path, creator, suppressVersionCheck);
             }
+        }
 
-            var id = jsonObject.GetValueOrDefault<string>("id");
-
-            var sections = new List<IntermediateSection>();
-
-            var sectionsJson = jsonObject.GetValueOrDefault<JsonArray>("sections");
-            foreach (JsonObject sectionJson in sectionsJson)
-            {
-                var section = IntermediateSection.Deserialize(creator, sectionJson);
-                sections.Add(section);
-            }
-
-            var localizations = new Dictionary<string, Localization>(StringComparer.OrdinalIgnoreCase);
-
-            //var localizationsJson = jsonObject.GetValueOrDefault<JsonArray>("localizations") ?? new JsonArray();
-            //foreach (JsonObject localizationJson in localizationsJson)
-            //{
-            //    var localization = Localization.Deserialize(localizationJson);
-            //    localizations.Add(localization.Culture, localization);
-            //}
-
-            return new Intermediate(id, sections, localizations, null);
+        /// <summary>
+        /// Loads an intermediate from a path on disk.
+        /// </summary>
+        /// <param name="stream">Stream to intermediate file.</param>
+        /// <param name="creator">ITupleDefinitionCreator to use when reconstituting the intermediate.</param>
+        /// <param name="suppressVersionCheck">Suppress checking for wix.dll version mismatches.</param>
+        /// <returns>Returns the loaded intermediate.</returns>
+        public static Intermediate Load(Stream stream, ITupleDefinitionCreator creator, bool suppressVersionCheck = false)
+        {
+            return Load(stream, "<unknown>", creator, suppressVersionCheck);
         }
 
         /// <summary>
@@ -183,6 +170,21 @@ namespace WixToolset.Data
 
                 jsonObject.Add("sections", sectionsJson);
 
+                var customDefinitions = GetCustomDefinitionsInSections();
+
+                if (customDefinitions.Count > 0)
+                {
+                    var customDefinitionsJson = new JsonArray(customDefinitions.Count);
+
+                    foreach (var kvp in customDefinitions.OrderBy(d => d.Key))
+                    {
+                        var customDefinitionJson = kvp.Value.Serialize();
+                        customDefinitionsJson.Add(customDefinitionJson);
+                    }
+
+                    jsonObject.Add("definitions", customDefinitionsJson);
+                }
+
                 //if (this.Localizations.Any())
                 //{
                 //    var localizationsJson = new JsonArray();
@@ -200,6 +202,73 @@ namespace WixToolset.Data
             }
         }
 
+        /// <summary>
+        /// Loads an intermediate from a path on disk.
+        /// </summary>
+        /// <param name="stream">Stream to intermediate file.</param>
+        /// <param name="path">Path name of intermediate file.</param>
+        /// <param name="creator">ITupleDefinitionCreator to use when reconstituting the intermediate.</param>
+        /// <param name="suppressVersionCheck">Suppress checking for wix.dll version mismatches.</param>
+        /// <returns>Returns the loaded intermediate.</returns>
+        internal static Intermediate Load(Stream stream, string path, ITupleDefinitionCreator creator, bool suppressVersionCheck = false)
+        {
+            JsonObject jsonObject;
+
+            using (var fs = FileStructure.Read(stream))
+            {
+                if (FileFormat.WixIR != fs.FileFormat)
+                {
+                    throw new WixUnexpectedFileFormatException(path, FileFormat.WixIR, fs.FileFormat);
+                }
+
+                var json = fs.GetData();
+                jsonObject = SimpleJson.DeserializeObject(json) as JsonObject;
+            }
+
+            if (!suppressVersionCheck)
+            {
+                var versionJson = jsonObject.GetValueOrDefault<string>("version");
+
+                if (!Version.TryParse(versionJson, out var version) || !Intermediate.CurrentVersion.Equals(version))
+                {
+                    throw new WixException(WixDataErrors.VersionMismatch(SourceLineNumber.CreateFromUri(path), "intermediate", versionJson, Intermediate.CurrentVersion.ToString()));
+                }
+            }
+
+            var definitionsJson = jsonObject.GetValueOrDefault<JsonArray>("definitions");
+
+            if (definitionsJson != null)
+            {
+                foreach (JsonObject definitionJson in definitionsJson)
+                {
+                    var definition = IntermediateTupleDefinition.Deserialize(definitionJson);
+                    creator.AddCustomTupleDefinition(definition);
+                }
+            }
+
+            var id = jsonObject.GetValueOrDefault<string>("id");
+
+            var sections = new List<IntermediateSection>();
+
+            var sectionsJson = jsonObject.GetValueOrDefault<JsonArray>("sections");
+            foreach (JsonObject sectionJson in sectionsJson)
+            {
+                var section = IntermediateSection.Deserialize(creator, sectionJson);
+                sections.Add(section);
+            }
+
+            var localizations = new Dictionary<string, Localization>(StringComparer.OrdinalIgnoreCase);
+
+            //var localizationsJson = jsonObject.GetValueOrDefault<JsonArray>("localizations") ?? new JsonArray();
+            //foreach (JsonObject localizationJson in localizationsJson)
+            //{
+            //    var localization = Localization.Deserialize(localizationJson);
+            //    localizations.Add(localization.Culture, localization);
+            //}
+
+            return new Intermediate(id, sections, localizations, null);
+        }
+
 #if false
         /// <summary>
         /// Loads an intermediate from a path on disk.
@@ -344,5 +413,20 @@ namespace WixToolset.Data
             writer.WriteEndElement();
         }
 #endif
+
+        private Dictionary<string, IntermediateTupleDefinition> GetCustomDefinitionsInSections()
+        {
+            var customDefinitions = new Dictionary<string, IntermediateTupleDefinition>();
+
+            foreach (var tuple in this.Sections.SelectMany(s => s.Tuples).Where(t => t.Definition.Type == TupleDefinitionType.MustBeFromAnExtension))
+            {
+                if (!customDefinitions.ContainsKey(tuple.Definition.Name))
+                {
+                    customDefinitions.Add(tuple.Definition.Name, tuple.Definition);
+                }
+            }
+
+            return customDefinitions;
+        }
     }
 }
diff --git a/src/WixToolset.Data/IntermediateFieldExtensions.cs b/src/WixToolset.Data/IntermediateFieldExtensions.cs
index c551b455..be225452 100644
--- a/src/WixToolset.Data/IntermediateFieldExtensions.cs
+++ b/src/WixToolset.Data/IntermediateFieldExtensions.cs
@@ -11,6 +11,8 @@ namespace WixToolset.Data
 
         public static IntermediateField Set(this IntermediateField field, object value)
         {
+            var data = value;
+
             if (field == null)
             {
                 throw new ArgumentNullException(nameof(field));
@@ -21,30 +23,72 @@ namespace WixToolset.Data
             }
             else if (field.Type == IntermediateFieldType.Bool && !(value is bool))
             {
-                throw new ArgumentException(nameof(value));
+                if (value is int)
+                {
+                    data = ((int)value) != 0;
+                }
+                else if (value is string str)
+                {
+                    if (str.Equals("yes", StringComparison.OrdinalIgnoreCase) || str.Equals("true", StringComparison.OrdinalIgnoreCase))
+                    {
+                        data = true;
+                    }
+                    else if (str.Equals("no", StringComparison.OrdinalIgnoreCase) || str.Equals("false", StringComparison.OrdinalIgnoreCase))
+                    {
+                        data = false;
+                    }
+                    else
+                    {
+                        throw new ArgumentException(nameof(value));
+                    }
+                }
+                else
+                {
+                    throw new ArgumentException(nameof(value));
+                }
             }
             else if (field.Type == IntermediateFieldType.Number && !(value is int))
             {
-                throw new ArgumentException(nameof(value));
+                if (value is string str && Int32.TryParse(str, out var number))
+                {
+                    data = number;
+                }
+                else
+                {
+                    throw new ArgumentException(nameof(value));
+                }
             }
             else if (field.Type == IntermediateFieldType.String && !(value is string))
             {
-                throw new ArgumentException(nameof(value));
-            }
-            else if (field.Type == IntermediateFieldType.Path && !(value is IntermediateFieldPathValue || value is string))
-            {
-                throw new ArgumentException(nameof(value));
-            }
-
-            if (field.Type == IntermediateFieldType.Path && value != null && value is string)
-            {
-                value = new IntermediateFieldPathValue { Path = (string)value };
+                if (value is int)
+                {
+                    data = value.ToString();
+                }
+                else if (value is bool b)
+                {
+                    data = b ? "true" : "false";
+                }
+                else
+                {
+                    throw new ArgumentException(nameof(value));
+                }
+            }
+            else if (field.Type == IntermediateFieldType.Path && !(value is IntermediateFieldPathValue))
+            {
+                if (value is string str)
+                {
+                    data = new IntermediateFieldPathValue { Path = str };
+                }
+                else
+                {
+                    throw new ArgumentException(nameof(value));
+                }
             }
 
             field.Value = new IntermediateFieldValue
             {
                 Context = valueContext,
-                Data = value,
+                Data = data,
                 PreviousValue = field.Value
             };
 
@@ -103,7 +147,7 @@ namespace WixToolset.Data
                     return field.Value.AsNumber() != 0;
 
                 case IntermediateFieldType.String:
-                    return !System.String.IsNullOrEmpty(field.Value.AsString());
+                    return !String.IsNullOrEmpty(field.Value.AsString());
 
                 default:
                     throw new InvalidCastException($"Cannot convert field {field.Name} with type {field.Type} to boolean");
diff --git a/src/WixToolset.Data/IntermediateFieldValueExtensions.cs b/src/WixToolset.Data/IntermediateFieldValueExtensions.cs
index bc106d4b..9a4237d8 100644
--- a/src/WixToolset.Data/IntermediateFieldValueExtensions.cs
+++ b/src/WixToolset.Data/IntermediateFieldValueExtensions.cs
@@ -2,26 +2,71 @@
 
 namespace WixToolset.Data
 {
+    using System;
+
     public static class IntermediateFieldValueExtensions
     {
         public static bool AsBool(this IntermediateFieldValue value)
         {
-            return value?.Data == null ? false : (bool)value.Data;
+            var result = value.AsNullableBool();
+            return result.HasValue && result.Value;
         }
 
         public static bool? AsNullableBool(this IntermediateFieldValue value)
         {
-            return (bool?)value?.Data;
+            if (value?.Data == null)
+            {
+                return null;
+            }
+            else if (value.Data is bool b)
+            {
+                return b;
+            }
+            else if (value.Data is int n)
+            {
+                return n != 0;
+            }
+            else if (value.Data is string s)
+            {
+                if (s.Equals("yes", StringComparison.OrdinalIgnoreCase) || s.Equals("true", StringComparison.OrdinalIgnoreCase))
+                {
+                    return true;
+                }
+                else if (s.Equals("no", StringComparison.OrdinalIgnoreCase) || s.Equals("false", StringComparison.OrdinalIgnoreCase))
+                {
+                    return false;
+                }
+            }
+
+            return (bool)value.Data;
         }
 
         public static int AsNumber(this IntermediateFieldValue value)
         {
-            return value?.Data == null ? 0 : (int)value.Data;
+            var result = value.AsNullableNumber();
+            return result ?? 0;
         }
 
         public static int? AsNullableNumber(this IntermediateFieldValue value)
         {
-            return (int?)value?.Data;
+            if (value?.Data == null)
+            {
+                return null;
+            }
+            else if (value.Data is int n)
+            {
+                return n;
+            }
+            else if (value.Data is bool b)
+            {
+                return b ? 1 : 0;
+            }
+            else if (value.Data is string s)
+            {
+                return Convert.ToInt32(s);
+            }
+
+            return (int)value.Data;
         }
 
         public static IntermediateFieldPathValue AsPath(this IntermediateFieldValue value)
@@ -31,7 +76,28 @@ namespace WixToolset.Data
 
         public static string AsString(this IntermediateFieldValue value)
         {
-            return (string)value?.Data;
+            if (value?.Data == null)
+            {
+                return null;
+            }
+            else if (value.Data is string s)
+            {
+                return s;
+            }
+            else if (value.Data is int n)
+            {
+                return n.ToString();
+            }
+            else if (value.Data is bool b)
+            {
+                return b ? "true" : "false";
+            }
+            else if (value.Data is IntermediateFieldPathValue p)
+            {
+                return p.Path;
+            }
+
+            return (string)value.Data;
         }
     }
 }
diff --git a/src/WixToolset.Data/IntermediateSection.cs b/src/WixToolset.Data/IntermediateSection.cs
index 2b1f7375..5d17eb31 100644
--- a/src/WixToolset.Data/IntermediateSection.cs
+++ b/src/WixToolset.Data/IntermediateSection.cs
@@ -66,7 +66,6 @@ namespace WixToolset.Data
             var codepage = jsonObject.GetValueOrDefault("codepage", 0);
             var id = jsonObject.GetValueOrDefault<string>("id");
             var type = jsonObject.GetEnumOrDefault("type", SectionType.Unknown);
-            var tuplesJson = jsonObject.GetValueOrDefault<JsonArray>("tuples");
 
             if (null == id && (SectionType.Unknown != type && SectionType.Fragment != type))
             {
@@ -80,6 +79,8 @@ namespace WixToolset.Data
 
             var section = new IntermediateSection(id, type, codepage);
 
+            var tuplesJson = jsonObject.GetValueOrDefault<JsonArray>("tuples");
+
             foreach (JsonObject tupleJson in tuplesJson)
             {
                 var tuple = IntermediateTuple.Deserialize(creator, tupleJson);
diff --git a/src/WixToolset.Data/IntermediateTuple.cs b/src/WixToolset.Data/IntermediateTuple.cs
index 0f1e5965..cda133b5 100644
--- a/src/WixToolset.Data/IntermediateTuple.cs
+++ b/src/WixToolset.Data/IntermediateTuple.cs
@@ -6,9 +6,9 @@ namespace WixToolset.Data
 
     public class IntermediateTuple
     {
-        //public IntermediateTuple(IntermediateTupleDefinition definition) : this(definition, null, null)
-        //{
-        //}
+        public IntermediateTuple(IntermediateTupleDefinition definition) : this(definition, null, null)
+        {
+        }
 
         public IntermediateTuple(IntermediateTupleDefinition definition, SourceLineNumber sourceLineNumber, Identifier id = null)
         {
@@ -35,11 +35,11 @@ namespace WixToolset.Data
             var sourceLineNumbersJson = jsonObject.GetValueOrDefault<JsonObject>("ln");
             var fieldsJson = jsonObject.GetValueOrDefault<JsonArray>("fields");
 
-            creator.TryGetTupleDefinitionByName(definitionName, out var definition); // TODO: this isn't sufficient.
-            var tuple = definition.CreateTuple();
+            var id = (idJson == null) ? null : Identifier.Deserialize(idJson);
+            var sourceLineNumbers = (sourceLineNumbersJson == null) ? null : SourceLineNumber.Deserialize(sourceLineNumbersJson);
 
-            tuple.Id = (idJson == null) ? null : Identifier.Deserialize(idJson);
-            tuple.SourceLineNumbers = (sourceLineNumbersJson == null) ? null : SourceLineNumber.Deserialize(sourceLineNumbersJson);
+            creator.TryGetTupleDefinitionByName(definitionName, out var definition); // TODO: this isn't sufficient.
+            var tuple = definition.CreateTuple(sourceLineNumbers, id);
 
             for (var i = 0; i < fieldsJson.Count; ++i)
             {
diff --git a/src/WixToolset.Data/IntermediateTupleDefinition.cs b/src/WixToolset.Data/IntermediateTupleDefinition.cs
index 5658cfe9..eb4ab12e 100644
--- a/src/WixToolset.Data/IntermediateTupleDefinition.cs
+++ b/src/WixToolset.Data/IntermediateTupleDefinition.cs
@@ -3,6 +3,7 @@
 namespace WixToolset.Data
 {
     using System;
+    using SimpleJson;
 
     public class IntermediateTupleDefinition
     {
@@ -23,7 +24,7 @@ namespace WixToolset.Data
             this.FieldDefinitions = fieldDefinitions;
             this.StrongTupleType = strongTupleType ?? typeof(IntermediateTuple);
 #if DEBUG
-            if (!this.StrongTupleType.IsSubclassOf(typeof(IntermediateTuple))) throw new ArgumentException(nameof(strongTupleType));
+            if (this.StrongTupleType != typeof(IntermediateTuple) && !this.StrongTupleType.IsSubclassOf(typeof(IntermediateTuple))) throw new ArgumentException(nameof(strongTupleType));
 #endif
         }
 
@@ -43,5 +44,52 @@ namespace WixToolset.Data
 
             return result;
         }
+
+        internal static IntermediateTupleDefinition Deserialize(JsonObject jsonObject)
+        {
+            var name = jsonObject.GetValueOrDefault<string>("name");
+            var definitionsJson = jsonObject.GetValueOrDefault<JsonArray>("fields");
+
+            var fieldDefinitions = new IntermediateFieldDefinition[definitionsJson.Count];
+
+            for (var i = 0; i < definitionsJson.Count; ++i)
+            {
+                var definitionJson = (JsonObject)definitionsJson[i];
+                var fieldName = definitionJson.GetValueOrDefault<string>("name");
+                var fieldType = definitionJson.GetEnumOrDefault("type", IntermediateFieldType.String);
+                fieldDefinitions[i] = new IntermediateFieldDefinition(fieldName, fieldType);
+            }
+
+            return new IntermediateTupleDefinition(name, fieldDefinitions, null);
+        }
+
+        internal JsonObject Serialize()
+        {
+            var jsonObject = new JsonObject
+            {
+                { "name", this.Name }
+            };
+
+            var fieldsJson = new JsonArray(this.FieldDefinitions.Length);
+
+            foreach (var fieldDefinition in this.FieldDefinitions)
+            {
+                var fieldJson = new JsonObject
+                {
+                    { "name", fieldDefinition.Name },
+                };
+
+                if (fieldDefinition.Type != IntermediateFieldType.String)
+                {
+                    fieldJson.Add("type", fieldDefinition.Type.ToString().ToLowerInvariant());
+                }
+
+                fieldsJson.Add(fieldJson);
+            }
+
+            jsonObject.Add("fields", fieldsJson);
+
+            return jsonObject;
+        }
     }
 }
diff --git a/src/WixToolset.Data/IntermediateTupleExtensions.cs b/src/WixToolset.Data/IntermediateTupleExtensions.cs
index 9865c06a..615c21f9 100644
--- a/src/WixToolset.Data/IntermediateTupleExtensions.cs
+++ b/src/WixToolset.Data/IntermediateTupleExtensions.cs
@@ -8,7 +8,7 @@ namespace WixToolset.Data
         {
             var definition = tuple.Definition.FieldDefinitions[index];
 
-            var field = tuple.Fields[index].Set(definition, value); ;
+            var field = tuple.Fields[index].Set(definition, value);
 
             return tuple.Fields[index] = field;
         }
diff --git a/src/WixToolset.Data/SimpleTupleDefinitionCreator.cs b/src/WixToolset.Data/SimpleTupleDefinitionCreator.cs
index b9d0b620..6a86639a 100644
--- a/src/WixToolset.Data/SimpleTupleDefinitionCreator.cs
+++ b/src/WixToolset.Data/SimpleTupleDefinitionCreator.cs
@@ -2,12 +2,27 @@
 
 namespace WixToolset.Data
 {
+    using System.Collections.Generic;
+
     internal class SimpleTupleDefinitionCreator : ITupleDefinitionCreator
     {
+        private Dictionary<string, IntermediateTupleDefinition> CustomDefinitionByName { get; } = new Dictionary<string, IntermediateTupleDefinition>();
+
+        public void AddCustomTupleDefinition(IntermediateTupleDefinition definition)
+        {
+            this.CustomDefinitionByName.Add(definition.Name, definition);
+        }
+
         public bool TryGetTupleDefinitionByName(string name, out IntermediateTupleDefinition tupleDefinition)
         {
             tupleDefinition = TupleDefinitions.ByName(name);
+
+            if (tupleDefinition == null)
+            {
+                tupleDefinition = this.CustomDefinitionByName.GetValueOrDefault(name);
+            }
+
             return tupleDefinition != null;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/WixToolset.Data/Tuples/WixFileTuple.cs b/src/WixToolset.Data/Tuples/WixFileTuple.cs
index 88dc4c82..3581e2e6 100644
--- a/src/WixToolset.Data/Tuples/WixFileTuple.cs
+++ b/src/WixToolset.Data/Tuples/WixFileTuple.cs
@@ -131,9 +131,9 @@ namespace WixToolset.Data.Tuples
             set => this.Set((int)WixFileTupleFields.DiskId, value);
         }
 
-        public string Source
+        public IntermediateFieldPathValue Source
         {
-            get => this.Fields[(int)WixFileTupleFields.Source].AsPath()?.Path;
+            get => this.Fields[(int)WixFileTupleFields.Source].AsPath();
             set => this.Set((int)WixFileTupleFields.Source, value);
         }