10 files changed, 355 insertions, 28 deletions

diff --git a/src/ext/Bal/dnchost/dnchost.cpp b/src/ext/Bal/dnchost/dnchost.cpp
index 6c066f43..36970f83 100644
--- a/src/ext/Bal/dnchost/dnchost.cpp
+++ b/src/ext/Bal/dnchost/dnchost.cpp
@@ -76,6 +76,16 @@ extern "C" HRESULT WINAPI BootstrapperApplicationCreate(
         vstate.fInitialized = TRUE;
     }
 
+    if (vstate.prereqData.fAlwaysInstallPrereqs && !vstate.prereqData.fCompleted)
+    {
+        BalLog(BOOTSTRAPPER_LOG_LEVEL_STANDARD, "Loading prerequisite bootstrapper application since it's configured to always run before loading the runtime.");
+
+        hr = CreatePrerequisiteBA(&vstate, pEngine, pArgs, pResults);
+        BalExitOnFailure(hr, "Failed to create the pre-requisite bootstrapper application.");
+
+        ExitFunction();
+    }
+
     if (!vstate.fInitializedRuntime)
     {
         hr = LoadRuntime(&vstate);
@@ -214,6 +224,15 @@ static HRESULT LoadDncConfiguration(
     hr = StrAllocConcat(&pState->sczBaFactoryRuntimeConfigPath, L".runtimeconfig.json", 0);
     BalExitOnFailure(hr, "Failed to concat extension to runtime config path.");
 
+    hr = XmlSelectSingleNode(pixdManifest, L"/BootstrapperApplicationData/WixMbaPrereqOptions", &pixnHost);
+    BalExitOnOptionalXmlQueryFailure(hr, fXmlFound, "Failed to find WixMbaPrereqOptions element in bootstrapper application config.");
+
+    if (fXmlFound)
+    {
+        hr = XmlGetAttributeNumber(pixnHost, L"AlwaysInstallPrereqs", reinterpret_cast<DWORD*>(&pState->prereqData.fAlwaysInstallPrereqs));
+        BalExitOnOptionalXmlQueryFailure(hr, fXmlFound, "Failed to get AlwaysInstallPrereqs value.");
+    }
+
     pState->type = DNCHOSTTYPE_FDD;
 
     hr = XmlSelectSingleNode(pixdManifest, L"/BootstrapperApplicationData/WixDncOptions", &pixnHost);
diff --git a/src/ext/Bal/mbahost/mbahost.cpp b/src/ext/Bal/mbahost/mbahost.cpp
index 3de77a05..0b89fc58 100644
--- a/src/ext/Bal/mbahost/mbahost.cpp
+++ b/src/ext/Bal/mbahost/mbahost.cpp
@@ -24,6 +24,10 @@ static HRESULT GetAppDomain(
 static HRESULT LoadModulePaths(
     __in MBASTATE* pState
     );
+static HRESULT LoadMbaConfiguration(
+    __in MBASTATE* pState,
+    __in const BOOTSTRAPPER_CREATE_ARGS* pArgs
+    );
 static HRESULT CheckSupportedFrameworks(
     __in LPCWSTR wzConfigPath
     );
@@ -96,12 +100,28 @@ extern "C" HRESULT WINAPI BootstrapperApplicationCreate(
 
     if (!vstate.fInitialized)
     {
+        hr = XmlInitialize();
+        BalExitOnFailure(hr, "Failed to initialize XML.");
+
         hr = LoadModulePaths(&vstate);
         BalExitOnFailure(hr, "Failed to load the module paths.");
 
+        hr = LoadMbaConfiguration(&vstate, pArgs);
+        BalExitOnFailure(hr, "Failed to get the mba configuration.");
+
         vstate.fInitialized = TRUE;
     }
 
+    if (vstate.prereqData.fAlwaysInstallPrereqs && !vstate.prereqData.fCompleted)
+    {
+        BalLog(BOOTSTRAPPER_LOG_LEVEL_STANDARD, "Loading prerequisite bootstrapper application since it's configured to always run before loading the runtime.");
+
+        hr = CreatePrerequisiteBA(&vstate, pEngine, pArgs, pResults);
+        BalExitOnFailure(hr, "Failed to create the pre-requisite bootstrapper application.");
+
+        ExitFunction();
+    }
+
     if (!vstate.fInitializedRuntime)
     {
         hr = LoadRuntime(&vstate);
@@ -264,6 +284,35 @@ LExit:
     return hr;
 }
 
+static HRESULT LoadMbaConfiguration(
+    __in MBASTATE* pState,
+    __in const BOOTSTRAPPER_CREATE_ARGS* pArgs
+    )
+{
+    HRESULT hr = S_OK;
+    IXMLDOMDocument* pixdManifest = NULL;
+    IXMLDOMNode* pixnHost = NULL;
+    BOOL fXmlFound = FALSE;
+
+    hr = XmlLoadDocumentFromFile(pArgs->pCommand->wzBootstrapperApplicationDataPath, &pixdManifest);
+    BalExitOnFailure(hr, "Failed to load BalManifest '%ls'", pArgs->pCommand->wzBootstrapperApplicationDataPath);
+
+    hr = XmlSelectSingleNode(pixdManifest, L"/BootstrapperApplicationData/WixMbaPrereqOptions", &pixnHost);
+    BalExitOnOptionalXmlQueryFailure(hr, fXmlFound, "Failed to find WixMbaPrereqOptions element in bootstrapper application config.");
+
+    if (fXmlFound)
+    {
+        hr = XmlGetAttributeNumber(pixnHost, L"AlwaysInstallPrereqs", reinterpret_cast<DWORD*>(&pState->prereqData.fAlwaysInstallPrereqs));
+        BalExitOnOptionalXmlQueryFailure(hr, fXmlFound, "Failed to get AlwaysInstallPrereqs value.");
+    }
+
+LExit:
+    ReleaseObject(pixnHost);
+    ReleaseObject(pixdManifest);
+
+    return hr;
+}
+
 // Checks whether at least one of required supported frameworks is installed via the NETFX registry keys.
 static HRESULT CheckSupportedFrameworks(
     __in LPCWSTR wzConfigPath
@@ -280,9 +329,6 @@ static HRESULT CheckSupportedFrameworks(
     DWORD dwFrameworkInstalled = 0;
     BOOL fUpdatedManifest = FALSE;
 
-    hr = XmlInitialize();
-    ExitOnFailure(hr, "Failed to initialize XML.");
-
     hr = XmlLoadDocumentFromFile(wzConfigPath, &pixdManifest);
     ExitOnFailure(hr, "Failed to load bootstrapper config file from path: %ls", wzConfigPath);
 
@@ -342,8 +388,6 @@ LExit:
     ReleaseObject(pNodeList);
     ReleaseObject(pixdManifest);
 
-    XmlUninitialize();
-
     return hr;
 }
 
diff --git a/src/ext/Bal/test/WixToolsetTest.Bal/BalExtensionFixture.cs b/src/ext/Bal/test/WixToolsetTest.Bal/BalExtensionFixture.cs
index 9aea8c1d..43484855 100644
--- a/src/ext/Bal/test/WixToolsetTest.Bal/BalExtensionFixture.cs
+++ b/src/ext/Bal/test/WixToolsetTest.Bal/BalExtensionFixture.cs
@@ -107,7 +107,41 @@ namespace WixToolsetTest.Bal
         }
 
         [Fact]
-        public void CantBuildUsingMBAWithNoPrereqs()
+        public void CanBuildUsingMBAWithAlwaysInstallPrereqs()
+        {
+            using (var fs = new DisposableFileSystem())
+            {
+                var baseFolder = fs.GetFolder();
+                var bundleFile = Path.Combine(baseFolder, "bin", "test.exe");
+                var bundleSourceFolder = TestData.Get(@"TestData\MBA");
+                var intermediateFolder = Path.Combine(baseFolder, "obj");
+                var baFolderPath = Path.Combine(baseFolder, "ba");
+                var extractFolderPath = Path.Combine(baseFolder, "extract");
+
+                var compileResult = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(bundleSourceFolder, "AlwaysInstallPrereqsBundle.wxs"),
+                    "-ext", TestData.Get(@"WixToolset.Bal.wixext.dll"),
+                    "-intermediateFolder", intermediateFolder,
+                    "-o", bundleFile,
+                });
+
+                compileResult.AssertSuccess();
+
+                Assert.True(File.Exists(bundleFile));
+
+                var extractResult = BundleExtractor.ExtractBAContainer(null, bundleFile, baFolderPath, extractFolderPath);
+                extractResult.AssertSuccess();
+
+                var wixMbaPrereqOptionsElements = extractResult.SelectBADataNodes("/ba:BootstrapperApplicationData/ba:WixMbaPrereqOptions");
+                var wixMbaPrereqOptions = (XmlNode)Assert.Single(wixMbaPrereqOptionsElements);
+                Assert.Equal("<WixMbaPrereqOptions AlwaysInstallPrereqs='1' />", wixMbaPrereqOptions.GetTestXml());
+            }
+        }
+
+        [Fact]
+        public void CannotBuildUsingMBAWithNoPrereqs()
         {
             using (var fs = new DisposableFileSystem())
             {
@@ -133,7 +167,7 @@ namespace WixToolsetTest.Bal
         }
 
         [Fact]
-        public void CantBuildUsingOverridableWrongCase()
+        public void CannotBuildUsingOverridableWrongCase()
         {
             using (var fs = new DisposableFileSystem())
             {
diff --git a/src/ext/Bal/test/WixToolsetTest.Bal/TestData/MBA/AlwaysInstallPrereqsBundle.wxs b/src/ext/Bal/test/WixToolsetTest.Bal/TestData/MBA/AlwaysInstallPrereqsBundle.wxs
new file mode 100644
index 00000000..685fef7b
--- /dev/null
+++ b/src/ext/Bal/test/WixToolsetTest.Bal/TestData/MBA/AlwaysInstallPrereqsBundle.wxs
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs"
+     xmlns:bal="http://wixtoolset.org/schemas/v4/wxs/bal">
+    <Bundle Name="AlwaysInstallPrereqsBundle" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="{36E9E102-E0E4-4A91-941D-6681A49216E6}">
+        <BootstrapperApplication>
+            <bal:WixManagedBootstrapperApplicationHost AlwaysInstallPrereqs="yes" />
+        </BootstrapperApplication>
+        <Chain>
+            <ExePackage bal:PrereqPackage="yes" Permanent="yes" DetectCondition="none" SourceFile="runtimes\win-x86\native\wixnative.exe" />
+        </Chain>
+    </Bundle>
+</Wix>
diff --git a/src/ext/Bal/wixext/BalBurnBackendExtension.cs b/src/ext/Bal/wixext/BalBurnBackendExtension.cs
index 3b19ae78..d34c159a 100644
--- a/src/ext/Bal/wixext/BalBurnBackendExtension.cs
+++ b/src/ext/Bal/wixext/BalBurnBackendExtension.cs
@@ -24,6 +24,7 @@ namespace WixToolset.Bal
             BalSymbolDefinitions.WixMbaPrereqInformation,
             BalSymbolDefinitions.WixStdbaOptions,
             BalSymbolDefinitions.WixStdbaOverridableVariable,
+            BalSymbolDefinitions.WixMbaPrereqOptions,
         };
 
         protected override IReadOnlyCollection<IntermediateSymbolDefinition> SymbolDefinitions => BurnSymbolDefinitions;
diff --git a/src/ext/Bal/wixext/BalCompiler.cs b/src/ext/Bal/wixext/BalCompiler.cs
index 267345e7..1721f252 100644
--- a/src/ext/Bal/wixext/BalCompiler.cs
+++ b/src/ext/Bal/wixext/BalCompiler.cs
@@ -117,6 +117,7 @@ namespace WixToolset.Bal
 
             switch (parentElement.Name.LocalName)
             {
+                case "BundlePackage":
                 case "ExePackage":
                 case "MsiPackage":
                 case "MspPackage":
@@ -216,7 +217,7 @@ namespace WixToolset.Bal
                             case "PrereqPackage":
                                 if (YesNoType.Yes == this.ParseHelper.GetAttributeYesNoValue(sourceLineNumbers, attribute))
                                 {
-                                    if (!this.prereqInfoSymbolsByPackageId.TryGetValue(packageId, out prereqInfo))
+                                    if (!this.prereqInfoSymbolsByPackageId.TryGetValue(packageId, out _))
                                     {
                                         prereqInfo = section.AddSymbol(new WixMbaPrereqInformationSymbol(sourceLineNumbers)
                                         {
@@ -703,6 +704,7 @@ namespace WixToolset.Bal
         private void ParseWixManagedBootstrapperApplicationHostElement(Intermediate intermediate, IntermediateSection section, XElement node)
         {
             var sourceLineNumbers = this.ParseHelper.GetSourceLineNumbers(node);
+            bool alwaysInstallPrereqs = false;
             string logoFile = null;
             string themeFile = null;
             string localizationFile = null;
@@ -714,6 +716,9 @@ namespace WixToolset.Bal
                 {
                     switch (attrib.Name.LocalName)
                     {
+                        case "AlwaysInstallPrereqs":
+                            alwaysInstallPrereqs = this.ParseHelper.GetAttributeYesNoValue(sourceLineNumbers, attrib) == YesNoType.Yes;
+                            break;
                         case "LogoFile":
                             logoFile = this.ParseHelper.GetAttributeValue(sourceLineNumbers, attrib);
                             break;
@@ -792,6 +797,14 @@ namespace WixToolset.Bal
                 }
 
                 this.CreateBARef(section, sourceLineNumbers, node, baId);
+
+                if (alwaysInstallPrereqs)
+                {
+                    section.AddSymbol(new WixMbaPrereqOptionsSymbol(sourceLineNumbers, new Identifier(AccessModifier.Global, "WixMbaPrereqOptions"))
+                    {
+                        AlwaysInstallPrereqs = 1,
+                    });
+                }
             }
         }
 
@@ -802,6 +815,7 @@ namespace WixToolset.Bal
         private void ParseWixDotNetCoreBootstrapperApplicationHostElement(Intermediate intermediate, IntermediateSection section, XElement node)
         {
             var sourceLineNumbers = this.ParseHelper.GetSourceLineNumbers(node);
+            bool alwaysInstallPrereqs = false;
             string logoFile = null;
             string themeFile = null;
             string localizationFile = null;
@@ -814,6 +828,9 @@ namespace WixToolset.Bal
                 {
                     switch (attrib.Name.LocalName)
                     {
+                        case "AlwaysInstallPrereqs":
+                            alwaysInstallPrereqs = this.ParseHelper.GetAttributeYesNoValue(sourceLineNumbers, attrib) == YesNoType.Yes;
+                            break;
                         case "LogoFile":
                             logoFile = this.ParseHelper.GetAttributeValue(sourceLineNumbers, attrib);
                             break;
@@ -903,6 +920,14 @@ namespace WixToolset.Bal
                 }
 
                 this.CreateBARef(section, sourceLineNumbers, node, baId);
+
+                if (alwaysInstallPrereqs)
+                {
+                    section.AddSymbol(new WixMbaPrereqOptionsSymbol(sourceLineNumbers, new Identifier(AccessModifier.Global, "WixMbaPrereqOptions"))
+                    {
+                        AlwaysInstallPrereqs = 1,
+                    });
+                }
             }
         }
 
diff --git a/src/ext/Bal/wixext/Symbols/BalSymbolDefinitions.cs b/src/ext/Bal/wixext/Symbols/BalSymbolDefinitions.cs
index 90865621..9010ce2d 100644
--- a/src/ext/Bal/wixext/Symbols/BalSymbolDefinitions.cs
+++ b/src/ext/Bal/wixext/Symbols/BalSymbolDefinitions.cs
@@ -16,6 +16,7 @@ namespace WixToolset.Bal
         WixMbaPrereqInformation,
         WixStdbaOptions,
         WixStdbaOverridableVariable,
+        WixMbaPrereqOptions,
     }
 
     public static partial class BalSymbolDefinitions
@@ -60,6 +61,9 @@ namespace WixToolset.Bal
                 case BalSymbolDefinitionType.WixStdbaOverridableVariable:
                     return BalSymbolDefinitions.WixStdbaOverridableVariable;
 
+                case BalSymbolDefinitionType.WixMbaPrereqOptions:
+                    return BalSymbolDefinitions.WixMbaPrereqOptions;
+
                 default:
                     throw new ArgumentOutOfRangeException(nameof(type));
             }
@@ -75,6 +79,7 @@ namespace WixToolset.Bal
             WixMbaPrereqInformation.AddTag(BurnConstants.BootstrapperApplicationDataSymbolDefinitionTag);
             WixStdbaOptions.AddTag(BurnConstants.BootstrapperApplicationDataSymbolDefinitionTag);
             WixStdbaOverridableVariable.AddTag(BurnConstants.BootstrapperApplicationDataSymbolDefinitionTag);
+            WixMbaPrereqOptions.AddTag(BurnConstants.BootstrapperApplicationDataSymbolDefinitionTag);
         }
     }
 }
diff --git a/src/ext/Bal/wixext/Symbols/WixMbaPrereqOptionsSymbol.cs b/src/ext/Bal/wixext/Symbols/WixMbaPrereqOptionsSymbol.cs
new file mode 100644
index 00000000..66374579
--- /dev/null
+++ b/src/ext/Bal/wixext/Symbols/WixMbaPrereqOptionsSymbol.cs
@@ -0,0 +1,47 @@
+// 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.Bal
+{
+    using WixToolset.Data;
+    using WixToolset.Bal.Symbols;
+
+    public static partial class BalSymbolDefinitions
+    {
+        public static readonly IntermediateSymbolDefinition WixMbaPrereqOptions = new IntermediateSymbolDefinition(
+            BalSymbolDefinitionType.WixMbaPrereqOptions.ToString(),
+            new[]
+            {
+                new IntermediateFieldDefinition(nameof(WixMbaPrereqOptionsSymbolFields.AlwaysInstallPrereqs), IntermediateFieldType.Number),
+            },
+            typeof(WixMbaPrereqOptionsSymbol));
+    }
+}
+
+namespace WixToolset.Bal.Symbols
+{
+    using WixToolset.Data;
+
+    public enum WixMbaPrereqOptionsSymbolFields
+    {
+        AlwaysInstallPrereqs,
+    }
+
+    public class WixMbaPrereqOptionsSymbol : IntermediateSymbol
+    {
+        public WixMbaPrereqOptionsSymbol() : base(BalSymbolDefinitions.WixMbaPrereqOptions, null, null)
+        {
+        }
+
+        public WixMbaPrereqOptionsSymbol(SourceLineNumber sourceLineNumber, Identifier id = null) : base(BalSymbolDefinitions.WixMbaPrereqOptions, sourceLineNumber, id)
+        {
+        }
+
+        public IntermediateField this[WixMbaPrereqOptionsSymbolFields index] => this.Fields[(int)index];
+
+        public int AlwaysInstallPrereqs
+        {
+            get => this.Fields[(int)WixMbaPrereqOptionsSymbolFields.AlwaysInstallPrereqs].AsNumber();
+            set => this.Set((int)WixMbaPrereqOptionsSymbolFields.AlwaysInstallPrereqs, value);
+        }
+    }
+}
diff --git a/src/ext/Bal/wixstdba/WixStandardBootstrapperApplication.cpp b/src/ext/Bal/wixstdba/WixStandardBootstrapperApplication.cpp
index 3774f49c..9c0f9576 100644
--- a/src/ext/Bal/wixstdba/WixStandardBootstrapperApplication.cpp
+++ b/src/ext/Bal/wixstdba/WixStandardBootstrapperApplication.cpp
@@ -30,6 +30,8 @@ enum WIXSTDBA_STATE
     WIXSTDBA_STATE_HELP,
     WIXSTDBA_STATE_DETECTING,
     WIXSTDBA_STATE_DETECTED,
+    WIXSTDBA_STATE_PLANNING_PREREQS,
+    WIXSTDBA_STATE_PLANNED_PREREQS,
     WIXSTDBA_STATE_PLANNING,
     WIXSTDBA_STATE_PLANNED,
     WIXSTDBA_STATE_APPLYING,
@@ -49,6 +51,7 @@ enum WM_WIXSTDBA
     WM_WIXSTDBA_APPLY_PACKAGES,
     WM_WIXSTDBA_CHANGE_STATE,
     WM_WIXSTDBA_SHOW_FAILURE,
+    WM_WIXSTDBA_PLAN_PREREQS,
 };
 
 // This enum must be kept in the same order as the vrgwzPageNames array.
@@ -217,9 +220,11 @@ public: // IBootstrapperApplication
                     : "A restart is required by the prerequisites but the user delayed it. The bootstrapper application will be reloaded after the computer is restarted.");
             }
         }
-        else if (m_fPrereqInstalled)
+        else if (m_fPrereqInstalled || m_fPrereqSkipped)
         {
-            BalLog(BOOTSTRAPPER_LOG_LEVEL_STANDARD, "The prerequisites were successfully installed. The bootstrapper application will be reloaded.");
+            BalLog(BOOTSTRAPPER_LOG_LEVEL_STANDARD, m_fPrereqInstalled
+                ? "The prerequisites were successfully installed. The bootstrapper application will be reloaded."
+                : "The prerequisites were already installed. The bootstrapper application will be reloaded.");
             *pAction = BOOTSTRAPPER_SHUTDOWN_ACTION_RELOAD_BOOTSTRAPPER;
             m_pPrereqData->fCompleted = TRUE;
         }
@@ -275,13 +280,16 @@ public: // IBootstrapperApplication
             hr = S_OK;
         }
 
-        // If the UI should be visible, display it now and hide the splash screen
-        if (BOOTSTRAPPER_DISPLAY_NONE < m_command.display)
+        if (!m_fPreplanPrereqs)
         {
-            ::ShowWindow(m_pTheme->hwndParent, SW_SHOW);
-        }
+            // If the UI should be visible, display it now and hide the splash screen
+            if (BOOTSTRAPPER_DISPLAY_NONE < m_command.display)
+            {
+                ::ShowWindow(m_pTheme->hwndParent, SW_SHOW);
+            }
 
-        m_pEngine->CloseSplashScreen();
+            m_pEngine->CloseSplashScreen();
+        }
 
         return __super::OnDetectBegin(fCached, registrationType, cPackages, pfCancel);
     }
@@ -331,24 +339,37 @@ public: // IBootstrapperApplication
         if (fEvaluateConditions)
         {
             hrStatus = EvaluateConditions();
-
-            if (FAILED(hrStatus))
-            {
-                fSkipToPlan = FALSE;
-            }
         }
 
         SetState(WIXSTDBA_STATE_DETECTED, hrStatus);
 
-        if (fSkipToPlan)
+        if (SUCCEEDED(hrStatus))
         {
-            ::PostMessageW(m_hWnd, WM_WIXSTDBA_PLAN_PACKAGES, 0, m_command.action);
+            if (m_fPreplanPrereqs)
+            {
+                ::PostMessageW(m_hWnd, WM_WIXSTDBA_PLAN_PREREQS, 0, BOOTSTRAPPER_ACTION_INSTALL);
+            }
+            else if (fSkipToPlan)
+            {
+                ::PostMessageW(m_hWnd, WM_WIXSTDBA_PLAN_PACKAGES, 0, m_command.action);
+            }
         }
 
         return hr;
     }
 
 
+    virtual STDMETHODIMP OnPlanBegin(
+        __in DWORD cPackages,
+        __in BOOL* pfCancel
+        )
+    {
+        m_fPrereqPackagePlanned = FALSE;
+
+        return __super::OnPlanBegin(cPackages, pfCancel);
+    }
+
+
     virtual STDMETHODIMP OnPlanRelatedBundleType(
         __in_z LPCWSTR wzBundleId,
         __in BOOTSTRAPPER_RELATED_BUNDLE_PLAN_TYPE recommendedType,
@@ -484,24 +505,97 @@ public: // IBootstrapperApplication
     }
 
 
+    virtual STDMETHODIMP OnPlannedPackage(
+        __in_z LPCWSTR wzPackageId,
+        __in BOOTSTRAPPER_ACTION_STATE execute,
+        __in BOOTSTRAPPER_ACTION_STATE rollback,
+        __in BOOL fPlannedCache,
+        __in BOOL fPlannedUncache
+        )
+    {
+        if (m_fPrereq && BOOTSTRAPPER_ACTION_STATE_NONE != execute)
+        {
+            m_fPrereqPackagePlanned = TRUE;
+        }
+
+        return __super::OnPlannedPackage(wzPackageId, execute, rollback, fPlannedCache, fPlannedUncache);
+    }
+
+
     virtual STDMETHODIMP OnPlanComplete(
         __in HRESULT hrStatus
         )
     {
         HRESULT hr = S_OK;
+        BOOL fPlannedPrereqs = WIXSTDBA_STATE_PLANNING_PREREQS == m_state;
+        WIXSTDBA_STATE completedState = WIXSTDBA_STATE_PLANNED;
+        BOOL fApply = TRUE;
 
-        SetState(WIXSTDBA_STATE_PLANNED, hrStatus);
+        if (fPlannedPrereqs)
+        {
+            if (SUCCEEDED(hrStatus) && !m_fPrereqPackagePlanned)
+            {
+                // Nothing to do, so close and let the parent BA take over.
+                m_fPrereqSkipped = TRUE;
+                SetState(WIXSTDBA_STATE_APPLIED, S_OK);
+                ExitFunction();
+            }
+            else if (BOOTSTRAPPER_ACTION_HELP == m_command.action)
+            {
+                // If prereq packages were planned then the managed BA probably can't be loaded, so show the help from this BA.
 
-        if (SUCCEEDED(hrStatus))
+                // Need to force the state change since normally moving backwards is prevented.
+                ::PostMessageW(m_hWnd, WM_WIXSTDBA_CHANGE_STATE, 0, WIXSTDBA_STATE_HELP);
+
+                ::PostMessageW(m_hWnd, WM_WIXSTDBA_SHOW_HELP, 0, 0);                
+
+                ExitFunction();
+            }
+
+            completedState = WIXSTDBA_STATE_PLANNED_PREREQS;
+        }
+
+        SetState(completedState, hrStatus);
+
+        if (FAILED(hrStatus))
+        {
+            ExitFunction();
+        }
+
+        if (fPlannedPrereqs)
+        {
+            // If the UI should be visible, display it now and hide the splash screen
+            if (BOOTSTRAPPER_DISPLAY_NONE < m_command.display)
+            {
+                ::ShowWindow(m_pTheme->hwndParent, SW_SHOW);
+            }
+
+            m_pEngine->CloseSplashScreen();
+
+            fApply = BOOTSTRAPPER_DISPLAY_FULL > m_command.display ||
+                     BOOTSTRAPPER_RESUME_TYPE_REBOOT == m_command.resumeType;
+        }
+
+        if (fApply)
         {
             ::PostMessageW(m_hWnd, WM_WIXSTDBA_APPLY_PACKAGES, 0, 0);
         }
 
+    LExit:
+        return hr;
+    }
+
+
+    virtual STDMETHODIMP OnApplyBegin(
+        __in DWORD dwPhaseCount,
+        __in BOOL* pfCancel
+        )
+    {
         m_fStartedExecution = FALSE;
         m_dwCalculatedCacheProgress = 0;
         m_dwCalculatedExecuteProgress = 0;
 
-        return hr;
+        return __super::OnApplyBegin(dwPhaseCount, pfCancel);
     }
 
 
@@ -2149,6 +2243,7 @@ private:
         BOOL fRet = FALSE;
         MSG msg = { };
         DWORD dwQuit = 0;
+        WM_WIXSTDBA firstAction = WM_WIXSTDBA_DETECT_PACKAGES;
 
         // Initialize COM and theme.
         hr = ::CoInitialize(NULL);
@@ -2169,15 +2264,21 @@ private:
         if (FAILED(pThis->m_hrFinal))
         {
             pThis->SetState(WIXSTDBA_STATE_FAILED, hr);
-            ::PostMessageW(pThis->m_hWnd, WM_WIXSTDBA_SHOW_FAILURE, 0, 0);
+            firstAction = WM_WIXSTDBA_SHOW_FAILURE;
         }
         else
         {
             // Okay, we're ready for packages now.
             pThis->SetState(WIXSTDBA_STATE_INITIALIZED, hr);
-            ::PostMessageW(pThis->m_hWnd, BOOTSTRAPPER_ACTION_HELP == pThis->m_command.action ? WM_WIXSTDBA_SHOW_HELP : WM_WIXSTDBA_DETECT_PACKAGES, 0, 0);
+
+            if (!pThis->m_fPreplanPrereqs && BOOTSTRAPPER_ACTION_HELP == pThis->m_command.action)
+            {
+                firstAction = WM_WIXSTDBA_SHOW_HELP;
+            }
         }
 
+        ::PostMessageW(pThis->m_hWnd, firstAction, 0, 0);
+
         // message pump
         while (0 != (fRet = ::GetMessageW(&msg, NULL, 0, 0)))
         {
@@ -2647,7 +2748,7 @@ private:
 
         // Calculate the window style based on the theme style and command display value.
         dwWindowStyle = m_pTheme->dwStyle;
-        if (BOOTSTRAPPER_DISPLAY_NONE >= m_command.display)
+        if (BOOTSTRAPPER_DISPLAY_NONE >= m_command.display || m_fPreplanPrereqs)
         {
             dwWindowStyle &= ~WS_VISIBLE;
         }
@@ -2850,6 +2951,10 @@ private:
             pBA->OnShowFailure();
             return 0;
 
+        case WM_WIXSTDBA_PLAN_PREREQS:
+            pBA->OnPlanPrereqs(static_cast<BOOTSTRAPPER_ACTION>(lParam));
+            return 0;
+
         case WM_THMUTIL_CONTROL_WM_COMMAND:
             return pBA->OnThemeControlWmCommand(reinterpret_cast<THEME_CONTROLWMCOMMAND_ARGS*>(wParam), reinterpret_cast<THEME_CONTROLWMCOMMAND_RESULTS*>(lParam));
 
@@ -3141,6 +3246,30 @@ private:
 
 
     //
+    // OnPlanPrereqs - preplan the packages to see if the preqba can be skipped.
+    //
+    void OnPlanPrereqs(
+        __in BOOTSTRAPPER_ACTION action
+        )
+    {
+        HRESULT hr = S_OK;
+
+        m_plannedAction = action;
+
+        SetState(WIXSTDBA_STATE_PLANNING_PREREQS, hr);
+
+        hr = m_pEngine->Plan(action);
+        BalExitOnFailure(hr, "Failed to start planning prereq packages.");
+
+    LExit:
+        if (FAILED(hr))
+        {
+            SetState(WIXSTDBA_STATE_PLANNING_PREREQS, hr);
+        }
+    }
+
+
+    //
     // OnApply - apply the packages.
     //
     void OnApply()
@@ -3838,6 +3967,8 @@ LExit:
                 break;
 
             case WIXSTDBA_STATE_DETECTED: __fallthrough;
+            case WIXSTDBA_STATE_PLANNING_PREREQS: __fallthrough;
+            case WIXSTDBA_STATE_PLANNED_PREREQS: __fallthrough;
             case WIXSTDBA_STATE_PLANNING: __fallthrough;
             case WIXSTDBA_STATE_PLANNED: __fallthrough;
             case WIXSTDBA_STATE_APPLYING: __fallthrough;
@@ -3874,6 +4005,8 @@ LExit:
                 break;
 
             case WIXSTDBA_STATE_DETECTED:
+            case WIXSTDBA_STATE_PLANNING_PREREQS: __fallthrough;
+            case WIXSTDBA_STATE_PLANNED_PREREQS: __fallthrough;
                 switch (m_command.action)
                 {
                 case BOOTSTRAPPER_ACTION_INSTALL:
@@ -4124,7 +4257,10 @@ public:
 
         m_pPrereqData = pPrereqData;
         m_fPrereq = NULL != pPrereqData;
+        m_fPreplanPrereqs = m_fPrereq && m_pPrereqData->fAlwaysInstallPrereqs;
+        m_fPrereqPackagePlanned = FALSE;
         m_fPrereqInstalled = FALSE;
+        m_fPrereqSkipped = FALSE;
 
         pEngine->AddRef();
         m_pEngine = pEngine;
@@ -4405,7 +4541,10 @@ private:
 
     PREQBA_DATA* m_pPrereqData;
     BOOL m_fPrereq;
+    BOOL m_fPreplanPrereqs;
+    BOOL m_fPrereqPackagePlanned;
     BOOL m_fPrereqInstalled;
+    BOOL m_fPrereqSkipped;
 
     ITaskbarList3* m_pTaskbarList;
     UINT m_uTaskbarButtonCreatedMessage;
diff --git a/src/ext/Bal/wixstdba/inc/preqba.h b/src/ext/Bal/wixstdba/inc/preqba.h
index 93a547ed..ed339730 100644
--- a/src/ext/Bal/wixstdba/inc/preqba.h
+++ b/src/ext/Bal/wixstdba/inc/preqba.h
@@ -5,6 +5,7 @@
 struct PREQBA_DATA
 {
     HRESULT hrHostInitialization;
+    BOOL fAlwaysInstallPrereqs;
     BOOL fCompleted;
 };