Bug: new metatable in weak table can fool the GCv5.4

All-weak tables are not being revisited after being visited during
propagation; if it gets a new metatable after that, the new metatable
may not be marked.

1 files changed, 10 insertions, 0 deletions

diff --git a/testes/gc.lua b/testes/gc.lua
index 03093e34..f017f330 100644
--- a/testes/gc.lua
+++ b/testes/gc.lua
@@ -301,6 +301,16 @@ collectgarbage()
 assert(next(a) == string.rep('$', 11))
 
 
+if T then   -- bug since 5.3: all-weak tables are not being revisited
+  T.gcstate("propagate")
+  local t = setmetatable({}, {__mode = "kv"})
+  T.gcstate("atomic")   -- 't' was visited
+  setmetatable(t, {__mode = "kv"})
+  T.gcstate("pause")  -- its new metatable is not being visited
+  assert(getmetatable(t).__mode == "kv")
+end
+
+
 -- 'bug' in 5.1
 a = {}
 local t = {x = 10}