From 53daa9e33b7ffbb7c8fe5ab8cc41caee7ed673c7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Rivera?= <rene.rivera@disbelief.com>
Date: Thu, 13 Jun 2024 22:31:23 -0500
Subject: [PATCH] Fix the case of asking to initialize any msvc toolset when
 they are already initialized causing errors.

When having "using msvc : x.y ;" in  one config and doing "using msvc ;" in another would fail as the later would try and re-init x.y and error. With this change the empty msvc init will be a no-op as we already having toolsets to use.
---
 src/tools/msvc.jam | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/tools/msvc.jam b/src/tools/msvc.jam
index 5f304c807..c210b93b3 100644
--- a/src/tools/msvc.jam
+++ b/src/tools/msvc.jam
@@ -1272,6 +1272,13 @@ local rule configure-really ( version ? : options * )
 {
     local command = [ feature.get-values <command> : $(options) ] ;
 
+    # We don't try and register any more versions than what we already know
+    # about when ask to discover any available versions.
+    if ! $(version) && ! $(command) && [ $(.versions).used ]
+    {
+        return ;
+    }
+
     if ! $(version) && ! $(command)
     {
         # We were given neither a command, nor a version.