From d0c31cbff94b86ae00fddac89c6f404cc4229370 Mon Sep 17 00:00:00 2001
From: Georg Schwab <georg.schwab@emocean.io>
Date: Thu, 6 May 2021 11:26:09 +0200
Subject: [PATCH] Windows: Use real artifact versioning symlinks if possible

When cross compiling from Windows to a platform that uses SONAMEs, real
symlinks are now created for the VERSION and SOVERSION links instead of
copies, if the user has the necessary privileges.

Fixes: #22128
---
 Source/cmcmd.cxx | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/Source/cmcmd.cxx b/Source/cmcmd.cxx
index 30347f23b9..98946b64fb 100644
--- a/Source/cmcmd.cxx
+++ b/Source/cmcmd.cxx
@@ -1643,10 +1643,21 @@ cmsys::Status cmcmd::SymlinkInternal(std::string const& file,
   if (cmSystemTools::FileExists(link) || cmSystemTools::FileIsSymlink(link)) {
     cmSystemTools::RemoveFile(link);
   }
-#if defined(_WIN32) && !defined(__CYGWIN__)
-  return cmSystemTools::CopyFileAlways(file, link);
-#else
   std::string linktext = cmSystemTools::GetFilenameName(file);
+#if defined(_WIN32) && !defined(__CYGWIN__)
+  std::string errorMessage;
+  cmsys::Status status =
+    cmSystemTools::CreateSymlink(linktext, link, &errorMessage);
+  // Creating a symlink will fail with ERROR_PRIVILEGE_NOT_HELD if the user
+  // does not have SeCreateSymbolicLinkPrivilege, or if developer mode is not
+  // active. In that case, we try to copy the file.
+  if (status.GetWindows() == ERROR_PRIVILEGE_NOT_HELD) {
+    status = cmSystemTools::CopyFileAlways(file, link);
+  } else if (!status) {
+    cmSystemTools::Error(errorMessage);
+  }
+  return status;
+#else
   return cmSystemTools::CreateSymlink(linktext, link);
 #endif
 }