8 files changed, 33 insertions, 16 deletions

diff --git a/src/burn/engine/inc/engine.h b/src/burn/engine/inc/engine.h
index b80b4213..9b29dd84 100644
--- a/src/burn/engine/inc/engine.h
+++ b/src/burn/engine/inc/engine.h
@@ -9,6 +9,8 @@
 #define BURN_SECTION_MAGIC 0x00f14300
 #define BURN_SECTION_VERSION 0x00000002
 
+// This needs to be incremented whenever a breaking change is made to the Burn protocol.
+#define BURN_PROTOCOL_VERSION 1
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/src/burn/engine/pipe.cpp b/src/burn/engine/pipe.cpp
index 48be8785..80275b52 100644
--- a/src/burn/engine/pipe.cpp
+++ b/src/burn/engine/pipe.cpp
@@ -710,6 +710,7 @@ static HRESULT ChildPipeConnected(
     }
 
     // All is well, tell the parent process.
+    // TODO: consider sending BURN_PROTOCOL_VERSION as a way to verify compatibility.
     hr = FileWriteHandle(hPipe, reinterpret_cast<LPCBYTE>(&dwAck), sizeof(dwAck));
     ExitOnFailure(hr, "Failed to inform parent process that child is running.");
 
diff --git a/src/burn/engine/pseudobundle.cpp b/src/burn/engine/pseudobundle.cpp
index 91c6c14f..14dd2b77 100644
--- a/src/burn/engine/pseudobundle.cpp
+++ b/src/burn/engine/pseudobundle.cpp
@@ -4,8 +4,8 @@
 
 
 extern "C" HRESULT PseudoBundleInitialize(
-    __in DWORD64 qwEngineVersion,
     __in BURN_PACKAGE* pPackage,
+    __in BOOL fSupportsBurnProtocol,
     __in BOOL fPerMachine,
     __in_z LPCWSTR wzId,
     __in BOOTSTRAPPER_RELATION_TYPE relationType,
@@ -84,6 +84,9 @@ extern "C" HRESULT PseudoBundleInitialize(
     pPackage->qwSize = qwSize;
     pPackage->fVital = fVital;
 
+    pPackage->Exe.protocol = fSupportsBurnProtocol ? BURN_EXE_PROTOCOL_TYPE_BURN : BURN_EXE_PROTOCOL_TYPE_NONE;
+    pPackage->Exe.fSupportsAncestors = TRUE;
+
     hr = StrAllocString(&pPackage->sczId, wzId, 0);
     ExitOnFailure(hr, "Failed to copy key for pseudo bundle.");
 
@@ -131,12 +134,6 @@ extern "C" HRESULT PseudoBundleInitialize(
         pPackage->fUninstallable = TRUE;
     }
 
-    // Only support progress from engines that are compatible (aka: version greater than or equal to last protocol breaking change *and* versions that are older or the same as this engine).
-    pPackage->Exe.protocol = (FILEMAKEVERSION(3, 6, 2221, 0) <= qwEngineVersion && qwEngineVersion <= FILEMAKEVERSION(rmj, rmm, rup, rpr)) ? BURN_EXE_PROTOCOL_TYPE_BURN : BURN_EXE_PROTOCOL_TYPE_NONE;
-    
-    // All versions of Burn past v3.9 RTM support suppressing ancestors.
-    pPackage->Exe.fSupportsAncestors = FILEMAKEVERSION(3, 9, 1006, 0) <= qwEngineVersion;
-
     if (pDependencyProvider)
     {
         pPackage->rgDependencyProviders = (BURN_DEPENDENCY_PROVIDER*)MemAlloc(sizeof(BURN_DEPENDENCY_PROVIDER), TRUE);
@@ -310,7 +307,7 @@ extern "C" HRESULT PseudoBundleInitializeUpdateBundle(
     hr = StrAllocString(&pPackage->Exe.sczInstallArguments, wzInstallArguments, 0);
     ExitOnFailure(hr, "Failed to copy install arguments for update bundle package");
 
-    // Assume the update bundle has the same engine version as this one.
+    // Trust the BA to only use UPDATE_REPLACE_EMBEDDED when appropriate.
     pPackage->Exe.protocol = BURN_EXE_PROTOCOL_TYPE_BURN;
     pPackage->Exe.fSupportsAncestors = TRUE;
 
diff --git a/src/burn/engine/pseudobundle.h b/src/burn/engine/pseudobundle.h
index 0fd4cbdb..22132c5e 100644
--- a/src/burn/engine/pseudobundle.h
+++ b/src/burn/engine/pseudobundle.h
@@ -7,8 +7,8 @@ extern "C" {
 #endif
 
 HRESULT PseudoBundleInitialize(
-    __in DWORD64 qwEngineVersion,
     __in BURN_PACKAGE* pPackage,
+    __in BOOL fSupportsBurnProtocol,
     __in BOOL fPerMachine,
     __in_z LPCWSTR wzId,
     __in BOOTSTRAPPER_RELATION_TYPE relationType,
diff --git a/src/burn/engine/registration.cpp b/src/burn/engine/registration.cpp
index e06767e1..9cc4b199 100644
--- a/src/burn/engine/registration.cpp
+++ b/src/burn/engine/registration.cpp
@@ -671,6 +671,9 @@ extern "C" HRESULT RegistrationSessionBegin(
         hr = RegWriteStringFormatted(hkRegistration, BURN_REGISTRATION_REGISTRY_ENGINE_VERSION, L"%hs", szVerMajorMinorBuild);
         ExitOnFailure(hr, "Failed to write %ls value.", BURN_REGISTRATION_REGISTRY_ENGINE_VERSION);
 
+        hr = RegWriteNumber(hkRegistration, BURN_REGISTRATION_REGISTRY_ENGINE_PROTOCOL_VERSION, BURN_PROTOCOL_VERSION);
+        ExitOnFailure(hr, "Failed to write %ls value.", BURN_REGISTRATION_REGISTRY_ENGINE_PROTOCOL_VERSION);
+
         // DisplayIcon: [path to exe] and ",0" to refer to the first icon in the executable.
         hr = RegWriteStringFormatted(hkRegistration, REGISTRY_BUNDLE_DISPLAY_ICON, L"%s,0", pRegistration->sczCacheExecutablePath);
         ExitOnFailure(hr, "Failed to write %ls value.", REGISTRY_BUNDLE_DISPLAY_ICON);
diff --git a/src/burn/engine/registration.h b/src/burn/engine/registration.h
index f9411636..e33d5270 100644
--- a/src/burn/engine/registration.h
+++ b/src/burn/engine/registration.h
@@ -23,6 +23,7 @@ const LPCWSTR BURN_REGISTRATION_REGISTRY_BUNDLE_UPGRADE_CODE = L"BundleUpgradeCo
 const LPCWSTR BURN_REGISTRATION_REGISTRY_BUNDLE_DISPLAY_NAME = L"DisplayName";
 const LPCWSTR BURN_REGISTRATION_REGISTRY_BUNDLE_VERSION = L"BundleVersion";
 const LPCWSTR BURN_REGISTRATION_REGISTRY_ENGINE_VERSION = L"EngineVersion";
+const LPCWSTR BURN_REGISTRATION_REGISTRY_ENGINE_PROTOCOL_VERSION = L"EngineProtocolVersion";
 const LPCWSTR BURN_REGISTRATION_REGISTRY_BUNDLE_PROVIDER_KEY = L"BundleProviderKey";
 const LPCWSTR BURN_REGISTRATION_REGISTRY_BUNDLE_TAG = L"BundleTag";
 
diff --git a/src/burn/engine/relatedbundle.cpp b/src/burn/engine/relatedbundle.cpp
index d3c856a6..4a694ef6 100644
--- a/src/burn/engine/relatedbundle.cpp
+++ b/src/burn/engine/relatedbundle.cpp
@@ -21,7 +21,7 @@ static HRESULT LoadRelatedBundleFromKey(
     __in HKEY hkBundleId,
     __in BOOL fPerMachine,
     __in BOOTSTRAPPER_RELATION_TYPE relationType,
-    __inout BURN_RELATED_BUNDLE *pRelatedBundle
+    __in BURN_RELATED_BUNDLE *pRelatedBundle
     );
 
 
@@ -398,21 +398,34 @@ static HRESULT LoadRelatedBundleFromKey(
     __in HKEY hkBundleId,
     __in BOOL fPerMachine,
     __in BOOTSTRAPPER_RELATION_TYPE relationType,
-    __inout BURN_RELATED_BUNDLE* pRelatedBundle
+    __in BURN_RELATED_BUNDLE* pRelatedBundle
     )
 {
     HRESULT hr = S_OK;
     DWORD64 qwEngineVersion = 0;
+    DWORD dwEngineProtocolVersion = 0;
+    BOOL fSupportsBurnProtocol = FALSE;
     LPWSTR sczBundleVersion = NULL;
     LPWSTR sczCachePath = NULL;
     BOOL fCached = FALSE;
     DWORD64 qwFileSize = 0;
     BURN_DEPENDENCY_PROVIDER dependencyProvider = { };
 
-    hr = RegReadVersion(hkBundleId, BURN_REGISTRATION_REGISTRY_ENGINE_VERSION, &qwEngineVersion);
-    if (FAILED(hr))
+    // Only support progress from engines that are compatible.
+    hr = RegReadNumber(hkBundleId, BURN_REGISTRATION_REGISTRY_ENGINE_PROTOCOL_VERSION, &dwEngineProtocolVersion);
+    if (SUCCEEDED(hr))
+    {
+        fSupportsBurnProtocol = BURN_PROTOCOL_VERSION == dwEngineProtocolVersion;
+    }
+    else
     {
-        qwEngineVersion = 0;
+        // Rely on version checking (aka: version greater than or equal to last protocol breaking change *and* versions that are older or the same as this engine)
+        hr = RegReadVersion(hkBundleId, BURN_REGISTRATION_REGISTRY_ENGINE_VERSION, &qwEngineVersion);
+        if (SUCCEEDED(hr))
+        {
+            fSupportsBurnProtocol = (FILEMAKEVERSION(3, 6, 2221, 0) <= qwEngineVersion && qwEngineVersion <= FILEMAKEVERSION(rmj, rmm, rup, rpr));
+        }
+
         hr = S_OK;
     }
 
@@ -467,7 +480,7 @@ static HRESULT LoadRelatedBundleFromKey(
 
     pRelatedBundle->relationType = relationType;
 
-    hr = PseudoBundleInitialize(qwEngineVersion, &pRelatedBundle->package, fPerMachine, wzRelatedBundleId, pRelatedBundle->relationType,
+    hr = PseudoBundleInitialize(&pRelatedBundle->package, fSupportsBurnProtocol, fPerMachine, wzRelatedBundleId, pRelatedBundle->relationType,
                                 BOOTSTRAPPER_PACKAGE_STATE_PRESENT, fCached, sczCachePath, sczCachePath, NULL, qwFileSize, FALSE,
                                 L"-quiet", L"-repair -quiet", L"-uninstall -quiet",
                                 (dependencyProvider.sczKey && *dependencyProvider.sczKey) ? &dependencyProvider : NULL,
diff --git a/src/burn/test/BurnUnitTest/PlanTest.cpp b/src/burn/test/BurnUnitTest/PlanTest.cpp
index 627da49a..35ddb22f 100644
--- a/src/burn/test/BurnUnitTest/PlanTest.cpp
+++ b/src/burn/test/BurnUnitTest/PlanTest.cpp
@@ -1154,7 +1154,7 @@ namespace Bootstrapper
             pRelatedBundle->fPlannable = TRUE;
             pRelatedBundle->relationType = BOOTSTRAPPER_RELATION_UPGRADE;
 
-            hr = PseudoBundleInitialize(0, &pRelatedBundle->package, TRUE, wzId, pRelatedBundle->relationType, BOOTSTRAPPER_PACKAGE_STATE_PRESENT, TRUE, wzFilePath, wzFilePath, NULL, 0, FALSE, L"-quiet", L"-repair -quiet", L"-uninstall -quiet", &dependencyProvider, NULL, 0);
+            hr = PseudoBundleInitialize(&pRelatedBundle->package, TRUE, TRUE, wzId, pRelatedBundle->relationType, BOOTSTRAPPER_PACKAGE_STATE_PRESENT, TRUE, wzFilePath, wzFilePath, NULL, 0, FALSE, L"-quiet", L"-repair -quiet", L"-uninstall -quiet", &dependencyProvider, NULL, 0);
             NativeAssert::Succeeded(hr, "Failed to initialize related bundle to represent bundle: %ls", wzId);
 
             ++pRelatedBundles->cRelatedBundles;