From e801d2b2438e0841ec28f466b5b2dfa29b65bc62 Mon Sep 17 00:00:00 2001
From: huangqinjin <huangqinjin@gmail.com>
Date: Thu, 5 Sep 2024 00:49:55 +0800
Subject: [PATCH] VS: Make CMAKE_GENERATOR_INSTANCE usable without VS Installer

On Windows and Wine, both the COM interface and `vswhere` might not be
available.  `CMAKE_GENERATOR_INSTANCE` is still supposed to work since
commit 195d47e213 (VS: Allow CMAKE_GENERATOR_INSTANCE to specify
portable instance, 2021-10-21, v3.23.0-rc1~452^2).

Issue: #21639
---
 Source/cmVSSetupHelper.cxx | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Source/cmVSSetupHelper.cxx b/Source/cmVSSetupHelper.cxx
index 809117e11d..92661346ca 100644
--- a/Source/cmVSSetupHelper.cxx
+++ b/Source/cmVSSetupHelper.cxx
@@ -450,7 +450,8 @@ bool cmVSSetupAPIHelper::EnumerateAndChooseVSInstance()
 
   // Enumerate VS instances with either COM interface or Vswhere
   if (!EnumerateVSInstancesWithCOM(vecVSInstancesAll) &&
-      !EnumerateVSInstancesWithVswhere(vecVSInstancesAll)) {
+      !EnumerateVSInstancesWithVswhere(vecVSInstancesAll) &&
+      this->SpecifiedVSInstallLocation.empty()) {
     return false;
   }