From 050191460f2be645e0b6b54054b200fd9db7b0f7 Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Wed, 13 May 2020 13:41:29 +0100
Subject: [PATCH] Check for empty bus vectors and allow backwards vector specs.

Fixes https://gitlab.com/kicad/code/kicad/issues/4421
---
 eeschema/sch_connection.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/eeschema/sch_connection.cpp b/eeschema/sch_connection.cpp
index 61486f7b8b..02542335fb 100644
--- a/eeschema/sch_connection.cpp
+++ b/eeschema/sch_connection.cpp
@@ -522,6 +522,11 @@ bool SCH_CONNECTION::ParseBusVector( const wxString& aBus, wxString* aName,
     if( braceNesting != 0 )
         return false;
 
+    if( begin == end )
+        return false;
+    else if( begin > end )
+        std::swap( begin, end );
+
     if( aName )
         *aName = prefix;