TRACK: Cope with negative depths and nil tracks

1 files changed, 6 insertions, 1 deletions

diff --git a/lib/supple/track.lua b/lib/supple/track.lua
index c652281..b22156f 100644
--- a/lib/supple/track.lua
+++ b/lib/supple/track.lua
@@ -27,7 +27,9 @@ end
 
 local function leave(...)
    if depth then
-      depth = depth - 1
+      if depth > 0 then
+	 depth = depth - 1
+      end
       record("<<<", ...)
    end
 end
@@ -37,6 +39,9 @@ local function start_tracking()
 end
 
 local function stop_tracking()
+   if track == nil then
+      return "***NO TRACKING DATA***"
+   end
    local ret = {}
    for i = 1, #track do
       local ent = track[i]