scripts/cd in rvm-0.1.39 vs scripts/cd in rvm-0.1.40

@@ -6,20 +6,32 @@
   cd() {
     builtin cd "$@"
     local cwd ; cwd=$(pwd)
     while : ; do
       if [[ -z "$cwd" ]] || [[ "$HOME" = "$cwd" ]] || [[ "/" = "$cwd" ]] ; then
-        if [[ "$rvm_project_rvmrc_default" -eq 1 ]] ; then
-          rvm default 1>/dev/null 2>&1
+        if [[ ! -z "$rvm_rvmrc_cwd" ]] ; then
+          if [[ -z "$rvm_previous_environment" ]] ; then
+            rvm default 1>/dev/null 2>&1
+          else
+            rvm "$rvm_previous_environment"  1>/dev/null 2>&1
+          fi 
+          unset rvm_rvmrc_cwd rvm_previous_environment
         fi
         break
       else
         if [[ -f "$cwd/.rvmrc" ]] ; then
-          source "$cwd/.rvmrc"
+          if [[ "$rvm_rvmrc_cwd" != "$cwd" ]] ; then
+            if [[ -z "$rvm_previous_environment" ]] ; then
+              rvm_previous_environment="$(__rvm_environment_identifier)"
+            fi
+            rvm_rvmrc_cwd="$cwd"
+            source "$cwd/.rvmrc"
+          fi
           break
         else
           cwd=$(dirname "$cwd")
         fi
       fi
     done
+    
   }
 fi