15 files changed, 333 insertions, 35 deletions

diff --git a/src/api/wix/WixToolset.Extensibility/Data/BundleVariableNameRule.cs b/src/api/wix/WixToolset.Extensibility/Data/BundleVariableNameRule.cs
new file mode 100644
index 00000000..eb6f7543
--- /dev/null
+++ b/src/api/wix/WixToolset.Extensibility/Data/BundleVariableNameRule.cs
@@ -0,0 +1,33 @@
+// 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.Extensibility.Data
+{
+    using System;
+
+    /// <summary>
+    /// When validating a bundle variable name, which special restrictions to ignore.
+    /// </summary>
+    [Flags]
+    public enum BundleVariableNameRule
+    {
+        /// <summary>
+        /// Enforce all special restrictions.
+        /// </summary>
+        EnforceAllRestrictions = 0x0,
+
+        /// <summary>
+        /// Allow names of built-in variables.
+        /// </summary>
+        CanBeBuiltIn = 0x1,
+
+        /// <summary>
+        /// Allow names of well-known variables.
+        /// </summary>
+        CanBeWellKnown = 0x2,
+
+        /// <summary>
+        /// Allow names that are not built-in and are not well-known and start with 'Wix'.
+        /// </summary>
+        CanHaveReservedPrefix = 0x4,
+    }
+}
diff --git a/src/api/wix/WixToolset.Extensibility/Services/IBundleValidator.cs b/src/api/wix/WixToolset.Extensibility/Services/IBundleValidator.cs
index 43f65fc8..3753d16d 100644
--- a/src/api/wix/WixToolset.Extensibility/Services/IBundleValidator.cs
+++ b/src/api/wix/WixToolset.Extensibility/Services/IBundleValidator.cs
@@ -33,15 +33,35 @@ namespace WixToolset.Extensibility.Services
         bool ValidateBundleMsiPropertyName(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string propertyName);
 
         /// <summary>
-        /// Validates a Bundle variable name and displays an error for an illegal value.
+        /// Validates a Bundle variable name that is being used to declare a Variable in the bundle manifest and displays an error for an illegal value.
         /// </summary>
         /// <param name="sourceLineNumbers"></param>
         /// <param name="elementName"></param>
         /// <param name="attributeName"></param>
         /// <param name="variableName"></param>
-        /// <param name="allowBuiltIn">Whether to bypass checks for reserved values.</param>
         /// <returns>Whether the name is valid.</returns>
-        bool ValidateBundleVariableName(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName, bool allowBuiltIn);
+        bool ValidateBundleVariableNameDeclaration(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName);
+
+        /// <summary>
+        /// Validates a Bundle variable name that is being used to reference a Variable and displays an error for an illegal value.
+        /// </summary>
+        /// <param name="sourceLineNumbers"></param>
+        /// <param name="elementName"></param>
+        /// <param name="attributeName"></param>
+        /// <param name="variableName"></param>
+        /// <param name="nameRule"></param>
+        /// <returns>Whether the name is valid.</returns>
+        bool ValidateBundleVariableNameValue(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName, BundleVariableNameRule nameRule);
+
+        /// <summary>
+        /// Validates a Bundle variable name that is being used to set its value and displays an error for an illegal value.
+        /// </summary>
+        /// <param name="sourceLineNumbers"></param>
+        /// <param name="elementName"></param>
+        /// <param name="attributeName"></param>
+        /// <param name="variableName"></param>
+        /// <returns>Whether the name is valid.</returns>
+        bool ValidateBundleVariableNameTarget(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName);
 
         /// <summary>
         /// Validates a bundle condition and displays an error for an illegal value.
diff --git a/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs b/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs
index a8246b9b..3a3c2ceb 100644
--- a/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs
+++ b/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs
@@ -246,8 +246,9 @@ namespace WixToolset.Extensibility.Services
         /// </summary>
         /// <param name="sourceLineNumbers">Source line information about the owner element.</param>
         /// <param name="attribute">The attribute containing the value to get.</param>
+        /// <param name="nameRule">A rule for the contents of the value. If the contents do not follow the rule, an error is thrown.</param>
         /// <returns>The attribute's value.</returns>
-        string GetAttributeBundleVariableNameValue(SourceLineNumber sourceLineNumbers, XAttribute attribute);
+        string GetAttributeBundleVariableNameValue(SourceLineNumber sourceLineNumbers, XAttribute attribute, BundleVariableNameRule nameRule = BundleVariableNameRule.CanBeWellKnown | BundleVariableNameRule.CanHaveReservedPrefix);
 
         /// <summary>
         /// Get a guid attribute value and displays an error for an illegal guid value.
diff --git a/src/burn/test/BurnUnitTest/VariableTest.cpp b/src/burn/test/BurnUnitTest/VariableTest.cpp
index f864307c..8ee6e179 100644
--- a/src/burn/test/BurnUnitTest/VariableTest.cpp
+++ b/src/burn/test/BurnUnitTest/VariableTest.cpp
@@ -163,6 +163,39 @@ namespace Bootstrapper
         }
 
         [Fact]
+        void VariablesSetCustomWixVariableTest()
+        {
+            HRESULT hr = S_OK;
+            IXMLDOMElement* pixeBundle = NULL;
+            BURN_VARIABLES variables = { };
+
+            try
+            {
+                LPCWSTR wzDocument =
+                    L"<Bundle>"
+                    L"    <CommandLine Variables='upperCase' />"
+                    L"</Bundle>";
+
+                hr = VariableInitialize(&variables);
+                TestThrowOnFailure(hr, L"Failed to initialize variables.");
+
+                // load XML document
+                LoadBundleXmlHelper(wzDocument, &pixeBundle);
+
+                hr = VariablesParseFromXml(&variables, pixeBundle);
+                NativeAssert::Succeeded(hr, "Failed to parse variables from XML.");
+
+                hr = VariableSetString(&variables, L"WixCustomVariable", L"something", FALSE, FALSE);
+                NativeAssert::Succeeded(hr, "Failed to set 'WixCustomVariable' variable.");
+            }
+            finally
+            {
+                ReleaseObject(pixeBundle);
+                VariablesUninitialize(&variables);
+            }
+        }
+
+        [Fact]
         void VariablesFormatTest()
         {
             HRESULT hr = S_OK;
diff --git a/src/ext/Util/test/WixToolsetTest.Util/TestData/BundleWithSearches/BundleUsingDiscouragedVariableNames.wxs b/src/ext/Util/test/WixToolsetTest.Util/TestData/BundleWithSearches/BundleUsingDiscouragedVariableNames.wxs
new file mode 100644
index 00000000..68f46af8
--- /dev/null
+++ b/src/ext/Util/test/WixToolsetTest.Util/TestData/BundleWithSearches/BundleUsingDiscouragedVariableNames.wxs
@@ -0,0 +1,19 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs" xmlns:util="http://wixtoolset.org/schemas/v4/wxs/util">
+    <Bundle Name="!(loc.BundleName)" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+        <BootstrapperApplication>
+            <BootstrapperApplicationDll SourceFile="fakeba.dll" />
+        </BootstrapperApplication>
+
+        <util:RegistrySearch
+            Variable="WixCustomVariable"
+            Root="HKLM"
+            Key="SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Custom"
+            Value="Release"
+            Result="value"
+            Bitness="always64" />
+
+        <Chain>
+            <MsiPackage SourceFile="test.msi" />
+        </Chain>
+    </Bundle>
+</Wix>
diff --git a/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs b/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs
index 39b792b7..24641fce 100644
--- a/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs
+++ b/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs
@@ -297,6 +297,53 @@ namespace WixToolsetTest.Util
         }
 
         [Fact]
+        public void CanBuildBundleWithWarningsWithSearchesUsingDiscouragedVariableNames()
+        {
+            var folder = TestData.Get("TestData", "BundleWithSearches");
+            var rootFolder = TestData.Get();
+            var wixext = Path.Combine(rootFolder, "WixToolset.Util.wixext.dll");
+
+            using (var fs = new DisposableFileSystem())
+            {
+                var baseFolder = fs.GetFolder();
+                var intermediateFolder = Path.Combine(baseFolder, "obj");
+                var bundlePath = Path.Combine(baseFolder, @"bin\test.exe");
+                var baFolderPath = Path.Combine(baseFolder, "ba");
+                var extractFolderPath = Path.Combine(baseFolder, "extract");
+
+                var result = WixRunner.Execute(false, new[]
+                {
+                    "build",
+                    Path.Combine(folder, "BundleUsingDiscouragedVariableNames.wxs"),
+                    "-ext", wixext,
+                    "-loc", Path.Combine(folder, "Bundle.en-us.wxl"),
+                    "-bindpath", Path.Combine(folder, "data"),
+                    "-intermediateFolder", intermediateFolder,
+                    "-o", bundlePath,
+                });
+
+                var messages = result.Messages.Select(m => m.ToString()).ToList();
+                messages.Sort();
+
+                WixAssert.CompareLineByLine(new[]
+                {
+                    "The *Search/@Variable attribute's value begins with the reserved prefix 'Wix'. Some prefixes are reserved by the WiX toolset for well-known values. Change your attribute's value to not begin with the same prefix.",
+                }, messages.ToArray());
+
+                result.AssertSuccess();
+
+                var extractResult = BundleExtractor.ExtractBAContainer(null, bundlePath, baFolderPath, extractFolderPath);
+                extractResult.AssertSuccess();
+
+                var utilSearches = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/*[self::burn:ExtensionSearch or self::burn:DirectorySearch or self::burn:FileSearch or self::burn:MsiProductSearch or self::burn:RegistrySearch]");
+                WixAssert.CompareLineByLine(new[]
+                {
+                    @"<RegistrySearch Id='wrsvJmsaXS39nKFUh9CVvRE6SSC4qk' Variable='WixCustomVariable' Root='HKLM' Key='SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Custom' Value='Release' Win64='yes' Type='value' VariableType='string' />",
+                }, utilSearches);
+            }
+        }
+
+        [Fact]
         public void CannotBuildBundleWithSearchesUsingBuiltinVariableNames()
         {
             var folder = TestData.Get("TestData", "BundleWithSearches");
@@ -307,7 +354,6 @@ namespace WixToolsetTest.Util
             {
                 var baseFolder = fs.GetFolder();
                 var intermediateFolder = Path.Combine(baseFolder, "obj");
-                var bundlePath = Path.Combine(baseFolder, "bin", "test.exe");
 
                 var result = WixRunner.Execute(new[]
                 {
@@ -317,7 +363,7 @@ namespace WixToolsetTest.Util
                     "-loc", Path.Combine(folder, "Bundle.en-us.wxl"),
                     "-bindpath", Path.Combine(folder, "data"),
                     "-intermediateFolder", intermediateFolder,
-                    "-o", bundlePath
+                    "-o", "bundle.wixlib",
                 });
 
                 var messages = result.Messages.Select(m => m.ToString()).ToList();
@@ -325,13 +371,12 @@ namespace WixToolsetTest.Util
 
                 WixAssert.CompareLineByLine(new[]
                 {
-                    "The DirectorySearch/@Variable attribute's value, 'InstallerName', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFilesFolder', 'CompatibilityMode', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleCommandLineAction', 'WixBundleForcedRestartPackage', 'WixBundleElevated', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleTag', or 'WixBundleVersion'.",
-                    "The FileSearch/@Variable attribute's value, 'NativeMachine', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFilesFolder', 'CompatibilityMode', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleCommandLineAction', 'WixBundleForcedRestartPackage', 'WixBundleElevated', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleTag', or 'WixBundleVersion'.",
-                    "The ProductSearch/@Variable attribute's value, 'Date', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFilesFolder', 'CompatibilityMode', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleCommandLineAction', 'WixBundleForcedRestartPackage', 'WixBundleElevated', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleTag', or 'WixBundleVersion'.",
-                    "The RegistrySearch/@Variable attribute's value begins with the reserved prefix 'Wix'. Some prefixes are reserved by the WiX toolset for well-known values. Change your attribute's value to not begin with the same prefix.",
-                    "The RegistrySearch/@Variable attribute's value, 'VersionNT64', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFilesFolder', 'CompatibilityMode', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleCommandLineAction', 'WixBundleForcedRestartPackage', 'WixBundleElevated', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleTag', or 'WixBundleVersion'.",
-                    "The RegistrySearch/@Variable attribute's value, 'WixBundleAction', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFilesFolder', 'CompatibilityMode', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleCommandLineAction', 'WixBundleForcedRestartPackage', 'WixBundleElevated', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleTag', or 'WixBundleVersion'.",
-                    "The WindowsFeatureSearch/@Variable attribute's value, 'NTProductType', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFilesFolder', 'CompatibilityMode', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleCommandLineAction', 'WixBundleForcedRestartPackage', 'WixBundleElevated', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleTag', or 'WixBundleVersion'.",
+                    "The DirectorySearch/@Variable attribute's value, 'InstallerName', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
+                    "The FileSearch/@Variable attribute's value, 'NativeMachine', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
+                    "The ProductSearch/@Variable attribute's value, 'Date', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
+                    "The RegistrySearch/@Variable attribute's value, 'VersionNT64', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
+                    "The RegistrySearch/@Variable attribute's value, 'WixBundleAction', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
+                    "The WindowsFeatureSearch/@Variable attribute's value, 'NTProductType', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
                 }, messages.ToArray());
             }
         }
diff --git a/src/wix/WixToolset.Core.Burn/Bundles/PerformBundleBackendValidationCommand.cs b/src/wix/WixToolset.Core.Burn/Bundles/PerformBundleBackendValidationCommand.cs
index a37e874c..49a25c0a 100644
--- a/src/wix/WixToolset.Core.Burn/Bundles/PerformBundleBackendValidationCommand.cs
+++ b/src/wix/WixToolset.Core.Burn/Bundles/PerformBundleBackendValidationCommand.cs
@@ -163,7 +163,7 @@ namespace WixToolset.Core.Burn.Bundles
 
         private void ValidateSearch(WixSearchSymbol symbol)
         {
-            this.BackendHelper.ValidateBundleVariableName(symbol.SourceLineNumbers, "*Search", "Variable", symbol.Variable, allowBuiltIn: false);
+            this.BackendHelper.ValidateBundleVariableNameTarget(symbol.SourceLineNumbers, "*Search", "Variable", symbol.Variable);
 
             if (symbol.Condition != null)
             {
@@ -173,7 +173,7 @@ namespace WixToolset.Core.Burn.Bundles
 
         private void ValidateVariable(WixBundleVariableSymbol symbol)
         {
-            this.BackendHelper.ValidateBundleVariableName(symbol.SourceLineNumbers, "Variable", "Name", symbol.Id.Id, allowBuiltIn: false);
+            this.BackendHelper.ValidateBundleVariableNameDeclaration(symbol.SourceLineNumbers, "Variable", "Name", symbol.Id.Id);
         }
     }
 }
diff --git a/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs b/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs
index 58fdeca5..93e7fc20 100644
--- a/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs
+++ b/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs
@@ -190,9 +190,19 @@ namespace WixToolset.Core.Burn.ExtensibilityServices
             return this.bundleValidator.ValidateBundleMsiPropertyName(sourceLineNumbers, elementName, attributeName, propertyName);
         }
 
-        public bool ValidateBundleVariableName(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName, bool allowBuiltIn)
+        public bool ValidateBundleVariableNameDeclaration(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName)
         {
-            return this.bundleValidator.ValidateBundleVariableName(sourceLineNumbers, elementName, attributeName, variableName, allowBuiltIn);
+            return this.bundleValidator.ValidateBundleVariableNameDeclaration(sourceLineNumbers, elementName, attributeName, variableName);
+        }
+
+        public bool ValidateBundleVariableNameValue(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName, BundleVariableNameRule nameRule)
+        {
+            return this.bundleValidator.ValidateBundleVariableNameValue(sourceLineNumbers, elementName, attributeName, variableName, nameRule);
+        }
+
+        public bool ValidateBundleVariableNameTarget(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName)
+        {
+            return this.bundleValidator.ValidateBundleVariableNameTarget(sourceLineNumbers, elementName, attributeName, variableName);
         }
 
         public bool ValidateBundleCondition(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string condition, BundleConditionPhase phase)
diff --git a/src/wix/WixToolset.Core/CompilerWarnings.cs b/src/wix/WixToolset.Core/CompilerWarnings.cs
index 7fca29bb..ed221c3e 100644
--- a/src/wix/WixToolset.Core/CompilerWarnings.cs
+++ b/src/wix/WixToolset.Core/CompilerWarnings.cs
@@ -36,11 +36,21 @@ namespace WixToolset.Core
             return Message(sourceLineNumbers, Ids.ProvidesKeyNotFound, "The provider key with identifier {0} was not found in the Wix4DependencyProvider table. Related registry rows will not be removed from authoring.", id);
         }
 
+        public static Message ReadonlyLogVariableTarget(SourceLineNumber sourceLineNumbers, string element, string attribute, string name)
+        {
+            return Message(sourceLineNumbers, Ids.ReadonlyLogVariableTarget, "The {0}/@{1} attribute's value references the well-known log Variable '{2}' to change its value. This variable is set by the engine and is intended to be read-only. Change your attribute's value to reference a custom variable.", element, attribute, name);
+        }
+
         public static Message RequiresKeyNotFound(SourceLineNumber sourceLineNumbers, string id)
         {
             return Message(sourceLineNumbers, Ids.RequiresKeyNotFound, "The dependency key with identifier {0} was not found in the Wix4Dependency table. Related registry rows will not be removed from authoring.", id);
         }
 
+        public static Message ReservedBurnNamespaceWarning(SourceLineNumber sourceLineNumbers, string element, string attribute, string prefix)
+        {
+            return Message(sourceLineNumbers, Ids.ReservedBurnNamespaceWarning, "The {0}/@{1} attribute's value begins with the reserved prefix '{2}'. Some prefixes are reserved by the WiX toolset for well-known values. Change your attribute's value to not begin with the same prefix.", element, attribute, prefix);
+        }
+
         public static Message Win64Component(SourceLineNumber sourceLineNumbers, string componentId)
         {
             return Message(sourceLineNumbers, Ids.Win64Component, "The Provides element should not be authored in the 64-bit component with identifier {0}. The dependency feature may not work if installing this package on 64-bit Windows operating systems prior to Windows 7 and Windows Server 2008 R2. Set the Component/@Bitness attribute to \"always32\" to ensure the dependency feature works correctly on legacy operating systems.", componentId);
@@ -60,6 +70,8 @@ namespace WixToolset.Core
             Win64Component = 5435,
             DirectoryRefStandardDirectoryDeprecated = 5436,
             DefiningStandardDirectoryDeprecated = 5437,
+            ReadonlyLogVariableTarget = 5438,
+            ReservedBurnNamespaceWarning = 5439,
         } // 5400-5499 and 6600-6699 were the ranges for Dependency and Tag which are now in Core between CompilerWarnings and CompilerErrors.
     }
 }
diff --git a/src/wix/WixToolset.Core/ExtensibilityServices/BundleValidator.cs b/src/wix/WixToolset.Core/ExtensibilityServices/BundleValidator.cs
index 8717a3b9..838ffb88 100644
--- a/src/wix/WixToolset.Core/ExtensibilityServices/BundleValidator.cs
+++ b/src/wix/WixToolset.Core/ExtensibilityServices/BundleValidator.cs
@@ -109,6 +109,21 @@ namespace WixToolset.Core.ExtensibilityServices
                 "WixBundleVersion",
             });
 
+        // Well-known variables (from burn\engine\variable.cpp, "vrgWellKnownVariables", around line 304)
+        private static readonly List<string> WellKnownBundleVariables = new List<string>(
+            new string[] {
+                "WixBundleInProgressName",
+                "WixBundleLastUsedSource",
+                "WixBundleLayoutDirectory",
+                "WixBundleLog",
+                "WixBundleLog_*",
+                "WixBundleRollbackLog_*",
+                "WixBundleManufacturer",
+                "WixBundleName",
+                "WixBundleOriginalSource",
+                "WixBundleOriginalSourceFolder",
+            });
+
         private static readonly List<string> DisallowedMsiProperties = new List<string>(
             new string[] {
                 "ACTION",
@@ -156,7 +171,7 @@ namespace WixToolset.Core.ExtensibilityServices
             return relativePath;
         }
 
-        public bool ValidateBundleVariableName(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName, bool allowBuiltIn)
+        public bool ValidateBundleVariableNameDeclaration(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName)
         {
             if (String.IsNullOrEmpty(variableName))
             {
@@ -170,14 +185,14 @@ namespace WixToolset.Core.ExtensibilityServices
 
                 return false;
             }
-            else if (!allowBuiltIn && BuiltinBundleVariables.Contains(variableName))
+            else if (BuiltinBundleVariables.Contains(variableName))
             {
                 var illegalValues = CreateValueList(ValueListKind.Or, BuiltinBundleVariables);
                 this.Messaging.Write(ErrorMessages.IllegalAttributeValueWithIllegalList(sourceLineNumbers, elementName, attributeName, variableName, illegalValues));
 
                 return false;
             }
-            else if (!allowBuiltIn && variableName.StartsWith("Wix", StringComparison.OrdinalIgnoreCase))
+            else if (variableName.StartsWith("Wix", StringComparison.OrdinalIgnoreCase))
             {
                 this.Messaging.Write(ErrorMessages.ReservedBurnNamespaceViolation(sourceLineNumbers, elementName, attributeName, "Wix"));
 
@@ -189,6 +204,105 @@ namespace WixToolset.Core.ExtensibilityServices
             }
         }
 
+        public bool ValidateBundleVariableNameValue(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName, BundleVariableNameRule nameRule)
+        {
+            if (String.IsNullOrEmpty(variableName))
+            {
+                this.Messaging.Write(ErrorMessages.IllegalEmptyAttributeValue(sourceLineNumbers, elementName, attributeName));
+
+                return false;
+            }
+            else if (!Common.IsBundleVariableName(variableName))
+            {
+                this.Messaging.Write(CompilerErrors.IllegalBundleVariableName(sourceLineNumbers, elementName, attributeName, variableName));
+
+                return false;
+            }
+            else if (BuiltinBundleVariables.Contains(variableName))
+            {
+                var allowed = nameRule.HasFlag(BundleVariableNameRule.CanBeBuiltIn);
+                if (!allowed)
+                {
+                    var illegalValues = CreateValueList(ValueListKind.Or, BuiltinBundleVariables);
+                    this.Messaging.Write(ErrorMessages.IllegalAttributeValueWithIllegalList(sourceLineNumbers, elementName, attributeName, variableName, illegalValues));
+                }
+
+                return allowed;
+            }
+            else if (WellKnownBundleVariables.Contains(variableName) ||
+                variableName.StartsWith("WixBundleLog_", StringComparison.OrdinalIgnoreCase) ||
+                variableName.StartsWith("WixBundleRollbackLog_", StringComparison.OrdinalIgnoreCase))
+            {
+                var allowed = nameRule.HasFlag(BundleVariableNameRule.CanBeWellKnown);
+                if (!allowed)
+                {
+                    var illegalValues = CreateValueList(ValueListKind.Or, WellKnownBundleVariables);
+                    this.Messaging.Write(ErrorMessages.IllegalAttributeValueWithIllegalList(sourceLineNumbers, elementName, attributeName, variableName, illegalValues));
+                }
+
+                return allowed;
+            }
+            else if (variableName.StartsWith("Wix", StringComparison.OrdinalIgnoreCase))
+            {
+                var allowed = nameRule.HasFlag(BundleVariableNameRule.CanHaveReservedPrefix);
+                if (!allowed)
+                {
+                    this.Messaging.Write(ErrorMessages.ReservedBurnNamespaceViolation(sourceLineNumbers, elementName, attributeName, "Wix"));
+                }
+
+                return allowed;
+            }
+            else
+            {
+                return true;
+            }
+        }
+
+        public bool ValidateBundleVariableNameTarget(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string variableName)
+        {
+            if (String.IsNullOrEmpty(variableName))
+            {
+                this.Messaging.Write(ErrorMessages.IllegalEmptyAttributeValue(sourceLineNumbers, elementName, attributeName));
+
+                return false;
+            }
+            else if (!Common.IsBundleVariableName(variableName))
+            {
+                this.Messaging.Write(CompilerErrors.IllegalBundleVariableName(sourceLineNumbers, elementName, attributeName, variableName));
+
+                return false;
+            }
+            else if (BuiltinBundleVariables.Contains(variableName))
+            {
+                var illegalValues = CreateValueList(ValueListKind.Or, BuiltinBundleVariables);
+                this.Messaging.Write(ErrorMessages.IllegalAttributeValueWithIllegalList(sourceLineNumbers, elementName, attributeName, variableName, illegalValues));
+
+                return false;
+            }
+            else if (variableName.Equals("WixBundleLog", StringComparison.OrdinalIgnoreCase) ||
+                     variableName.StartsWith("WixBundleLog_", StringComparison.OrdinalIgnoreCase) ||
+                     variableName.StartsWith("WixBundleRollbackLog_", StringComparison.OrdinalIgnoreCase))
+            {
+                this.Messaging.Write(CompilerWarnings.ReadonlyLogVariableTarget(sourceLineNumbers, elementName, attributeName, variableName));
+
+                return true;
+            }
+            else if (WellKnownBundleVariables.Contains(variableName))
+            {
+                return true;
+            }
+            else if (variableName.StartsWith("Wix", StringComparison.OrdinalIgnoreCase))
+            {
+                this.Messaging.Write(CompilerWarnings.ReservedBurnNamespaceWarning(sourceLineNumbers, elementName, attributeName, "Wix"));
+
+                return true;
+            }
+            else
+            {
+                return true;
+            }
+        }
+
         public bool ValidateBundleMsiPropertyName(SourceLineNumber sourceLineNumbers, string elementName, string attributeName, string propertyName)
         {
             if (String.IsNullOrEmpty(propertyName))
diff --git a/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs b/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs
index 31607b02..5f4ac726 100644
--- a/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs
+++ b/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs
@@ -246,9 +246,9 @@ namespace WixToolset.Core.ExtensibilityServices
             {
                 this.Messaging.Write(ErrorMessages.ExpectedAttribute(sourceLineNumbers, elementName, "Variable"));
             }
-            else
+            else if (!this.IsValidLocIdentifier(variable) && !Common.IsValidBinderVariable(variable))
             {
-                this.BundleValidator.ValidateBundleVariableName(sourceLineNumbers, elementName, "Variable", variable, allowBuiltIn: false);
+                this.BundleValidator.ValidateBundleVariableNameValue(sourceLineNumbers, elementName, "Variable", variable, BundleVariableNameRule.CanBeWellKnown | BundleVariableNameRule.CanHaveReservedPrefix);
             }
 
             section.AddSymbol(new WixSearchSymbol(sourceLineNumbers, id)
@@ -322,19 +322,19 @@ namespace WixToolset.Core.ExtensibilityServices
 
             if (!String.IsNullOrEmpty(variableId?.Id))
             {
-                this.BundleValidator.ValidateBundleVariableName(sourceLineNumbers, attribute.Parent.Name.LocalName, attribute.Name.LocalName, variableId.Id, allowBuiltIn: false);
+                this.BundleValidator.ValidateBundleVariableNameDeclaration(sourceLineNumbers, attribute.Parent.Name.LocalName, attribute.Name.LocalName, variableId.Id);
             }
 
             return variableId;
         }
 
-        public string GetAttributeBundleVariableNameValue(SourceLineNumber sourceLineNumbers, XAttribute attribute)
+        public string GetAttributeBundleVariableNameValue(SourceLineNumber sourceLineNumbers, XAttribute attribute, BundleVariableNameRule nameRule = BundleVariableNameRule.CanBeWellKnown | BundleVariableNameRule.CanHaveReservedPrefix)
         {
             var variableName = this.GetAttributeValue(sourceLineNumbers, attribute);
 
-            if (!String.IsNullOrEmpty(variableName))
+            if (!String.IsNullOrEmpty(variableName) && !this.IsValidLocIdentifier(variableName) && !Common.IsValidBinderVariable(variableName))
             {
-                this.BundleValidator.ValidateBundleVariableName(sourceLineNumbers, attribute.Parent.Name.LocalName, attribute.Name.LocalName, variableName, allowBuiltIn: false);
+                this.BundleValidator.ValidateBundleVariableNameValue(sourceLineNumbers, attribute.Parent.Name.LocalName, attribute.Name.LocalName, variableName, nameRule);
             }
 
             return variableName;
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs
index b09506c0..9c636a8f 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/BadInputFixture.cs
@@ -7,6 +7,7 @@ namespace WixToolsetTest.CoreIntegration
     using System.Linq;
     using WixBuildTools.TestSupport;
     using WixToolset.Core.TestPackage;
+    using WixToolset.Data;
     using Xunit;
 
     public class BadInputFixture
@@ -179,12 +180,11 @@ namespace WixToolsetTest.CoreIntegration
 
                 WixAssert.CompareLineByLine(new[]
                 {
-                    "The SetVariable/@Variable attribute's value, '!(loc.BuiltinBurnVariableName)', is not a legal bundle variable name. Identifiers may contain ASCII characters A-Z, a-z, digits, or underscores (_). Every identifier must begin with either a letter or an underscore.",
                     "The Variable/@Name attribute was not found; it is required.",
                     "The Variable/@Name attribute's value, '!(loc.BuiltinBurnVariableName)', is not a legal identifier. Identifiers may contain ASCII characters A-Z, a-z, digits, underscores (_), or periods (.). Every identifier must begin with either a letter or an underscore.",
                 }, messages.ToArray());
 
-                Assert.Equal(6603, result.ExitCode);
+                Assert.Equal(10, result.ExitCode);
             }
         }
 
@@ -212,7 +212,6 @@ namespace WixToolsetTest.CoreIntegration
 
                 WixAssert.CompareLineByLine(new[]
                 {
-                    "The SetVariable/@Variable attribute's value begins with the reserved prefix 'Wix'. Some prefixes are reserved by the WiX toolset for well-known values. Change your attribute's value to not begin with the same prefix.",
                     "The SetVariable/@Variable attribute's value, 'WixBundleInstalled', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
                     "The Variable/@Name attribute's value begins with the reserved prefix 'Wix'. Some prefixes are reserved by the WiX toolset for well-known values. Change your attribute's value to not begin with the same prefix.",
                     "The Variable/@Name attribute's value, 'AppDataFolder', is one of the illegal options: 'AdminToolsFolder', 'AppDataFolder', 'CommonAppDataFolder', 'CommonFiles64Folder', 'CommonFiles6432Folder', 'CommonFilesFolder', 'CompatibilityMode', 'ComputerName', 'Date', 'DesktopFolder', 'FavoritesFolder', 'FontsFolder', 'InstallerName', 'InstallerVersion', 'LocalAppDataFolder', 'LogonUser', 'MyPicturesFolder', 'NativeMachine', 'NTProductType', 'NTSuiteBackOffice', 'NTSuiteDataCenter', 'NTSuiteEnterprise', 'NTSuitePersonal', 'NTSuiteSmallBusiness', 'NTSuiteSmallBusinessRestricted', 'NTSuiteWebServer', 'PersonalFolder', 'Privileged', 'ProcessorArchitecture', 'ProgramFiles64Folder', 'ProgramFiles6432Folder', 'ProgramFilesFolder', 'ProgramMenuFolder', 'RebootPending', 'SendToFolder', 'ServicePackLevel', 'StartMenuFolder', 'StartupFolder', 'System64Folder', 'SystemFolder', 'SystemLanguageID', 'TempFolder', 'TemplateFolder', 'TerminalServer', 'UserLanguageID', 'UserUILanguageID', 'VersionMsi', 'VersionNT', 'VersionNT64', 'WindowsBuildNumber', 'WindowsFolder', 'WindowsVolume', 'WixBundleAction', 'WixBundleActiveParent', 'WixBundleCommandLineAction', 'WixBundleElevated', 'WixBundleExecutePackageAction', 'WixBundleExecutePackageCacheFolder', 'WixBundleForcedRestartPackage', 'WixBundleInstalled', 'WixBundleProviderKey', 'WixBundleSourceProcessFolder', 'WixBundleSourceProcessPath', 'WixBundleTag', 'WixBundleUILevel', or 'WixBundleVersion'.",
@@ -232,7 +231,7 @@ namespace WixToolsetTest.CoreIntegration
                 var baseFolder = fs.GetFolder();
                 var intermediateFolder = Path.Combine(baseFolder, "obj");
 
-                var result = WixRunner.Execute(new[]
+                var result = WixRunner.Execute(false, new[]
                 {
                     "build",
                     Path.Combine(folder, "BundleWithInvalid", "BundleWithInvalidLocValues.wxs"),
@@ -244,21 +243,30 @@ namespace WixToolsetTest.CoreIntegration
                     "-o", Path.Combine(baseFolder, @"bin\test.exe")
                 });
 
-                var messages = result.Messages.Select(m => m.ToString()).ToList();
-                messages.Sort();
+                var warningMessages = result.Messages.Where(m => m.Level == MessageLevel.Warning).Select(m => m.ToString()).ToList();
+                warningMessages.Sort();
 
                 WixAssert.CompareLineByLine(new[]
                 {
                     "*Search/@Condition contains the built-in Variable 'WixBundleAction', which is not available when it is evaluated. (Unavailable Variables are: 'WixBundleAction'.). Rewrite the condition to avoid Variables that are never valid during its evaluation.",
                     "Bundle/@Condition contains the built-in Variable 'WixBundleInstalled', which is not available when it is evaluated. (Unavailable Variables are: 'RebootPending', 'WixBundleAction', or 'WixBundleInstalled'.). Rewrite the condition to avoid Variables that are never valid during its evaluation.",
                     "ExePackage/@DetectCondition contains the built-in Variable 'WixBundleAction', which is not available when it is evaluated. (Unavailable Variables are: 'WixBundleAction'.). Rewrite the condition to avoid Variables that are never valid during its evaluation.",
+                    "The *Search/@Variable attribute's value begins with the reserved prefix 'Wix'. Some prefixes are reserved by the WiX toolset for well-known values. Change your attribute's value to not begin with the same prefix.",
+                    "The *Search/@Variable attribute's value references the well-known log Variable 'WixBundleLog' to change its value. This variable is set by the engine and is intended to be read-only. Change your attribute's value to reference a custom variable.",
+                }, warningMessages.ToArray());
+
+                var errorMessages = result.Messages.Where(m => m.Level == MessageLevel.Error).Select(m => m.ToString()).ToList();
+                errorMessages.Sort();
+
+                WixAssert.CompareLineByLine(new[]
+                {
                     "The CommandLine/@Condition attribute's value '=' is not a valid bundle condition.",
                     "The MsiPackage/@InstallCondition attribute's value '=' is not a valid bundle condition.",
                     "The MsiProperty/@Condition attribute's value '=' is not a valid bundle condition.",
                     "The 'REINSTALLMODE' MsiProperty is controlled by the bootstrapper and cannot be authored. (Illegal properties are: 'ACTION', 'ADDLOCAL', 'ADDSOURCE', 'ADDDEFAULT', 'ADVERTISE', 'ALLUSERS', 'REBOOT', 'REINSTALL', 'REINSTALLMODE', or 'REMOVE'.) Remove the MsiProperty element.",
-                }, messages.ToArray());
+                }, errorMessages.ToArray());
 
-                Assert.Equal(1159, result.ExitCode);
+                Assert.Equal(409, result.ExitCode);
             }
         }
     }
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxl b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxl
index 0b5fac56..da2de367 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxl
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxl
@@ -1,6 +1,8 @@
 <WixLocalization xmlns="http://wixtoolset.org/schemas/v4/wxl" Culture="en-US">
   <String Id="BuiltinMsiPropertyName">REINSTALLMODE</String>
   <String Id="BuiltinBurnVariableName">WixBundleInstalled</String>
+  <String Id="BurnLogVariableName">WixBundleLog</String>
+  <String Id="BurnReservedPrefixVariableName">WixCustomVariable</String>
   <String Id="NonsenseDetectCondition">WixBundleAction = 4</String>
   <String Id="NonsenseExecuteCondition">=</String>
   <String Id="NonsenseGlobalCondition">WixBundleInstalled &lt;&gt; 1</String>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxs
index 74f66bbb..6e1a4dd7 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithInvalidLocValues.wxs
@@ -13,5 +13,7 @@
             </ExePackage>
         </Chain>
         <SetVariable Id="Builtin" Condition="!(loc.NonsenseDetectCondition)" Variable="FOO" Value="1" />
+        <SetVariable Id="LogWellKnown" Variable="!(loc.BurnLogVariableName)" Value="2" />
+        <SetVariable Id="ReservedPrefix" Variable="!(loc.BurnReservedPrefixVariableName)" Value="3" />
     </Bundle>
 </Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithReservedVariableNames.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithReservedVariableNames.wxs
index 3a38e2c9..af0e6625 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithReservedVariableNames.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleWithInvalid/BundleWithReservedVariableNames.wxs
@@ -1,7 +1,6 @@
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <Fragment>
         <SetVariable Id="Builtin" Variable="WixBundleInstalled" Value="1" />
-        <SetVariable Id="Builtin" Variable="WixDoesNotExist" Value="2" />
         <Variable Name="WixCustomVariable" />
         <Variable Name="AppDataFolder" />
     </Fragment>