From 8fbfd38b52e4e4c6381d10610211a5e66140c0c1 Mon Sep 17 00:00:00 2001
From: Philipp Gesang <phg42.2a@gmail.com>
Date: Tue, 5 Nov 2013 16:17:45 +0100
Subject: [tool] protect --list and --field against invalid queries

---
 luaotfload-tool.lua | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/luaotfload-tool.lua b/luaotfload-tool.lua
index 17d9399..3bae175 100755
--- a/luaotfload-tool.lua
+++ b/luaotfload-tool.lua
@@ -892,9 +892,17 @@ local get_fields get_fields = function (entry, fields, acc, n)
         local tmp   = entry
         for i = 1, #chain - 1 do
             tmp = tmp [chain [i]]
+            if not tmp then
+                --- invalid field
+                break
+            end
+        end
+        if tmp then
+            local value = tmp [chain [#chain]]
+            acc[#acc+1] = value or false
+        else
+            acc[#acc+1] = false
         end
-        local value = tmp [chain [#chain]]
-        acc[#acc+1] = value or false
         return get_fields (entry, fields, acc, n+1)
     end
     return acc
@@ -997,8 +1005,11 @@ actions.list = function (job)
                 local chain = stringsplit (criterion, "->")
                 for i = 1, #chain - 1 do
                     tmp = tmp [chain [i]]
+                    if not tmp then
+                        break
+                    end
                 end
-                local value = tmp [chain [#chain]]
+                local value = tmp and tmp [chain [#chain]] or "<none>"
                 if value then
                     --value = tostring(value)
                     local entries = by_category[value]
-- 
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