6 files changed, 90 insertions, 11 deletions

diff --git a/src/burn/engine/core.cpp b/src/burn/engine/core.cpp
index 9d4ea43e..37872e52 100644
--- a/src/burn/engine/core.cpp
+++ b/src/burn/engine/core.cpp
@@ -527,8 +527,15 @@ extern "C" HRESULT CorePlan(
             hr = PlanRelatedBundlesInitialize(&pEngineState->userExperience, &pEngineState->registration, pEngineState->command.relationType, &pEngineState->plan);
             ExitOnFailure(hr, "Failed to initialize related bundles for plan.");
 
-            hr = PlanRegistration(&pEngineState->plan, &pEngineState->registration, &pEngineState->dependencies, pEngineState->command.resumeType, pEngineState->command.relationType, &fContinuePlanning);
-            ExitOnFailure(hr, "Failed to plan registration.");
+            if (pEngineState->plan.fDowngrade)
+            {
+                fContinuePlanning = FALSE;
+            }
+            else
+            {
+                hr = PlanRegistration(&pEngineState->plan, &pEngineState->registration, &pEngineState->dependencies, pEngineState->command.resumeType, pEngineState->command.relationType, &fContinuePlanning);
+                ExitOnFailure(hr, "Failed to plan registration.");
+            }
 
             if (fContinuePlanning)
             {
@@ -615,6 +622,7 @@ extern "C" HRESULT CoreApply(
 {
     HRESULT hr = S_OK;
     HANDLE hLock = NULL;
+    BOOL fApplyBegan = FALSE;
     BOOL fApplyInitialize = FALSE;
     BOOL fElevated = FALSE;
     BOOL fRegistered = FALSE;
@@ -627,8 +635,6 @@ extern "C" HRESULT CoreApply(
     DWORD dwPhaseCount = 0;
     BOOTSTRAPPER_APPLYCOMPLETE_ACTION applyCompleteAction = BOOTSTRAPPER_APPLYCOMPLETE_ACTION_NONE;
 
-    LogId(REPORT_STANDARD, MSG_APPLY_BEGIN);
-
     if (!pEngineState->fPlanned)
     {
         ExitOnFailure(hr = E_INVALIDSTATE, "Apply cannot be done without a successful Plan.");
@@ -638,6 +644,10 @@ extern "C" HRESULT CoreApply(
         ExitOnFailure(hr = E_INVALIDSTATE, "Plans cannot be applied multiple times.");
     }
 
+    fApplyBegan = TRUE;
+
+    LogId(REPORT_STANDARD, MSG_APPLY_BEGIN);
+
     // Ensure any previous attempts to execute are reset.
     ApplyReset(&pEngineState->userExperience, &pEngineState->packages);
 
@@ -653,6 +663,14 @@ extern "C" HRESULT CoreApply(
     hr = UserExperienceOnApplyBegin(&pEngineState->userExperience, dwPhaseCount);
     ExitOnRootFailure(hr, "BA aborted apply begin.");
 
+    if (pEngineState->plan.fDowngrade)
+    {
+        hr = HRESULT_FROM_WIN32(ERROR_PRODUCT_VERSION);
+        UserExperienceOnApplyDowngrade(&pEngineState->userExperience, &hr);
+
+        ExitFunction();
+    }
+
     pEngineState->plan.fAffectedMachineState = pEngineState->plan.fCanAffectMachineState;
 
     hr = ApplyLock(FALSE, &hLock);
@@ -804,13 +822,16 @@ LExit:
         DeleteCriticalSection(&applyContext.csApply);
     }
 
-    UserExperienceOnApplyComplete(&pEngineState->userExperience, hr, restart, &applyCompleteAction);
-    if (BOOTSTRAPPER_APPLYCOMPLETE_ACTION_RESTART == applyCompleteAction)
+    if (fApplyBegan)
     {
-        pEngineState->fRestart = TRUE;
-    }
+        UserExperienceOnApplyComplete(&pEngineState->userExperience, hr, restart, &applyCompleteAction);
+        if (BOOTSTRAPPER_APPLYCOMPLETE_ACTION_RESTART == applyCompleteAction)
+        {
+            pEngineState->fRestart = TRUE;
+        }
 
-    LogId(REPORT_STANDARD, MSG_APPLY_COMPLETE, hr, LoggingRestartToString(restart), LoggingBoolToString(pEngineState->fRestart));
+        LogId(REPORT_STANDARD, MSG_APPLY_COMPLETE, hr, LoggingRestartToString(restart), LoggingBoolToString(pEngineState->fRestart));
+    }
 
     return hr;
 }
diff --git a/src/burn/engine/engine.mc b/src/burn/engine/engine.mc
index a5c4e2ba..53e6b256 100644
--- a/src/burn/engine/engine.mc
+++ b/src/burn/engine/engine.mc
@@ -499,6 +499,20 @@ Language=English
 Ignoring bundle dependents due to action UnsafeUninstall...
 .
 
+MessageId=224
+Severity=Warning
+SymbolicName=MSG_PLAN_SKIPPED_DUE_TO_DOWNGRADE
+Language=English
+Plan skipped due to related bundle of plan type Downgrade:
+.
+
+MessageId=225
+Severity=Warning
+SymbolicName=MSG_UPGRADE_BUNDLE_DOWNGRADE
+Language=English
+    id: %1!ls!, version: %2!ls!
+.
+
 MessageId=299
 Severity=Success
 SymbolicName=MSG_PLAN_COMPLETE
diff --git a/src/burn/engine/plan.cpp b/src/burn/engine/plan.cpp
index dcb919c7..46680636 100644
--- a/src/burn/engine/plan.cpp
+++ b/src/burn/engine/plan.cpp
@@ -1328,11 +1328,12 @@ LExit:
 extern "C" HRESULT PlanRelatedBundlesInitialize(
     __in BURN_USER_EXPERIENCE* pUserExperience,
     __in BURN_REGISTRATION* pRegistration,
-    __in BOOTSTRAPPER_RELATION_TYPE /*relationType*/,
-    __in BURN_PLAN* /*pPlan*/
+    __in BOOTSTRAPPER_RELATION_TYPE relationType,
+    __in BURN_PLAN* pPlan
     )
 {
     HRESULT hr = S_OK;
+    BOOL fUninstalling = BOOTSTRAPPER_ACTION_UNINSTALL == pPlan->action || BOOTSTRAPPER_ACTION_UNSAFE_UNINSTALL == pPlan->action;
 
     for (DWORD i = 0; i < pRegistration->relatedBundles.cRelatedBundles; ++i)
     {
@@ -1356,6 +1357,19 @@ extern "C" HRESULT PlanRelatedBundlesInitialize(
 
         hr = UserExperienceOnPlanRelatedBundleType(pUserExperience, pRelatedBundle->package.sczId, &pRelatedBundle->planRelationType);
         ExitOnRootFailure(hr, "BA aborted plan related bundle type.");
+
+        if (BOOTSTRAPPER_RELATED_BUNDLE_PLAN_TYPE_DOWNGRADE == pRelatedBundle->planRelationType &&
+            pRelatedBundle->fPlannable && !fUninstalling && BOOTSTRAPPER_RELATION_UPGRADE != relationType)
+        {
+            if (!pPlan->fDowngrade)
+            {
+                pPlan->fDowngrade = TRUE;
+
+                LogId(REPORT_STANDARD, MSG_PLAN_SKIPPED_DUE_TO_DOWNGRADE);
+            }
+
+            LogId(REPORT_VERBOSE, MSG_UPGRADE_BUNDLE_DOWNGRADE, pRelatedBundle->package.sczId, pRelatedBundle->pVersion->sczVersion);
+        }
     }
 
     RelatedBundlesSortPlan(&pRegistration->relatedBundles);
@@ -3011,6 +3025,7 @@ extern "C" void PlanDump(
     LogStringLine(PlanDumpLevel, "     can affect machine state: %hs", LoggingTrueFalseToString(pPlan->fCanAffectMachineState));
     LogStringLine(PlanDumpLevel, "     disable-rollback: %hs", LoggingTrueFalseToString(pPlan->fDisableRollback));
     LogStringLine(PlanDumpLevel, "     disallow-removal: %hs", LoggingTrueFalseToString(pPlan->fDisallowRemoval));
+    LogStringLine(PlanDumpLevel, "     downgrade: %hs", LoggingTrueFalseToString(pPlan->fDowngrade));
     LogStringLine(PlanDumpLevel, "     registration options: %hs", LoggingRegistrationOptionsToString(pPlan->dwRegistrationOperations));
     LogStringLine(PlanDumpLevel, "     estimated size: %llu", pPlan->qwEstimatedSize);
     if (pPlan->sczLayoutDirectory)
diff --git a/src/burn/engine/plan.h b/src/burn/engine/plan.h
index 1f3fe07c..e73cbcfa 100644
--- a/src/burn/engine/plan.h
+++ b/src/burn/engine/plan.h
@@ -250,6 +250,7 @@ typedef struct _BURN_PLAN
     BOOL fAffectedMachineState;
     LPWSTR sczLayoutDirectory;
     BOOL fPlanPackageCacheRollback;
+    BOOL fDowngrade;
 
     DWORD64 qwCacheSizeTotal;
 
diff --git a/src/burn/engine/userexperience.cpp b/src/burn/engine/userexperience.cpp
index 8668cf6f..81ce8bb9 100644
--- a/src/burn/engine/userexperience.cpp
+++ b/src/burn/engine/userexperience.cpp
@@ -335,6 +335,30 @@ LExit:
     return hr;
 }
 
+EXTERN_C BAAPI UserExperienceOnApplyDowngrade(
+    __in BURN_USER_EXPERIENCE* pUserExperience,
+    __inout HRESULT* phrStatus
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONAPPLYDOWNGRADE_ARGS args = { };
+    BA_ONAPPLYDOWNGRADE_RESULTS results = { };
+
+    args.cbSize = sizeof(args);
+    args.hrRecommended = *phrStatus;
+
+    results.cbSize = sizeof(results);
+    results.hrStatus = *phrStatus;
+
+    hr = SendBAMessage(pUserExperience, BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE, &args, &results);
+    ExitOnFailure(hr, "BA OnApplyDowngrade failed.");
+
+    *phrStatus = results.hrStatus;
+
+LExit:
+    return hr;
+}
+
 EXTERN_C BAAPI UserExperienceOnBeginMsiTransactionBegin(
     __in BURN_USER_EXPERIENCE* pUserExperience,
     __in LPCWSTR wzTransactionId
diff --git a/src/burn/engine/userexperience.h b/src/burn/engine/userexperience.h
index 11344365..2f18acdd 100644
--- a/src/burn/engine/userexperience.h
+++ b/src/burn/engine/userexperience.h
@@ -110,6 +110,10 @@ BAAPI UserExperienceOnApplyComplete(
     __in BOOTSTRAPPER_APPLY_RESTART restart,
     __inout BOOTSTRAPPER_APPLYCOMPLETE_ACTION* pAction
     );
+BAAPI UserExperienceOnApplyDowngrade(
+    __in BURN_USER_EXPERIENCE* pUserExperience,
+    __inout HRESULT* phrStatus
+    );
 BAAPI UserExperienceOnBeginMsiTransactionBegin(
     __in BURN_USER_EXPERIENCE* pUserExperience,
     __in LPCWSTR wzTransactionId