From fafdaa522ff2a3888dfceb0ab56911c4f8cdf48d Mon Sep 17 00:00:00 2001
From: Bob Arnson <bob@firegiant.com>
Date: Wed, 21 Jan 2026 21:20:40 -0500
Subject: Allow patched package to be uninstalled.

Normally, a patched package is detected as superseded and therefore a
normal uninstall takes no action. This change looks for applied patches
and allows a normal uninstall to remove the package.

Fixes https://github.com/wixtoolset/issues/issues/6350
---
 src/burn/engine/msiengine.cpp | 52 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

(limited to 'src/burn/engine/msiengine.cpp')

diff --git a/src/burn/engine/msiengine.cpp b/src/burn/engine/msiengine.cpp
index 86fb0d9d..a2a29bda 100644
--- a/src/burn/engine/msiengine.cpp
+++ b/src/burn/engine/msiengine.cpp
@@ -50,7 +50,9 @@ static void RegisterSourceDirectory(
     __in BURN_PACKAGE* pPackage,
     __in_z LPCWSTR wzCacheDirectory
     );
-
+static BOOL PackageHasAppliedPatch(
+    __in BURN_PACKAGE* pPackage
+    );
 
 // function definitions
 
@@ -904,7 +906,9 @@ extern "C" HRESULT MsiEnginePlanCalculatePackage(
         else if ((BOOTSTRAPPER_REQUEST_STATE_ABSENT == pPackage->requested || BOOTSTRAPPER_REQUEST_STATE_CACHE == pPackage->requested) &&
                  !pPackage->fPermanent) // removing a package that should be removed.
         {
-            execute = BOOTSTRAPPER_PACKAGE_STATE_SUPERSEDED == pPackage->currentState ? BOOTSTRAPPER_ACTION_STATE_NONE : BOOTSTRAPPER_ACTION_STATE_UNINSTALL;
+            BOOL fPackageHasAppliedPatch = PackageHasAppliedPatch(pPackage);
+
+            execute = BOOTSTRAPPER_PACKAGE_STATE_SUPERSEDED == pPackage->currentState && !fPackageHasAppliedPatch ? BOOTSTRAPPER_ACTION_STATE_NONE : BOOTSTRAPPER_ACTION_STATE_UNINSTALL;
         }
         else if (BOOTSTRAPPER_REQUEST_STATE_FORCE_ABSENT == pPackage->requested)
         {
@@ -2265,6 +2269,7 @@ LExit:
     ReleaseStr(sczMspPath);
     ReleaseStr(sczCachedDirectory);
     ReleaseStr(sczPatches);
+
     return hr;
 }
 
@@ -2289,6 +2294,47 @@ static void RegisterSourceDirectory(
 
 LExit:
     ReleaseStr(sczMsiDirectory);
+}
+
+static BOOL PackageHasAppliedPatch(
+    __in BURN_PACKAGE* pPackage
+)
+{
+    HRESULT hr = S_OK;
+    BOOL fPatched = FALSE;
+    UINT er = ERROR_SUCCESS;
+    DWORD iPatch = 0;
+    WCHAR wzPatchCode[MAX_GUID_CHARS + 1] = {};
+    WCHAR wzTransforms[MAX_PATH] = {};
+    DWORD cchTransforms = countof(wzTransforms);
+    WCHAR wzPatchState[2] = {};
+    DWORD cchPatchState = countof(wzPatchState);
+
+    for (;;)
+    {
+        er = ::MsiEnumPatchesW(pPackage->Msi.sczProductCode, iPatch, wzPatchCode, wzTransforms, &cchTransforms);
+
+        if (ERROR_NO_MORE_ITEMS == er)
+        {
+            ExitFunction();
+        }
+        ExitOnWin32Error(er, hr, "Failed to enumerate patches for package %ls, product code %ls.", pPackage->sczId, pPackage->Msi.sczProductCode);
+
+        er = ::MsiGetPatchInfoExW(wzPatchCode, pPackage->Msi.sczProductCode, NULL, pPackage->fPerMachine ? MSIINSTALLCONTEXT_MACHINE : MSIINSTALLCONTEXT_USERUNMANAGED
+            , INSTALLPROPERTY_PATCHSTATE, wzPatchState, &cchPatchState);
+        ExitOnWin32Error(er, hr, "Failed to get patch info for patch %ls.", wzPatchCode);
+
+        if ('1' == wzPatchState[0])
+        {
+            fPatched = TRUE;
+
+            ExitFunction();
+        }
+
+        ++iPatch;
+    }
+
+LExit:
+    return fPatched;
 
-    return;
 }
-- 
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