Avoid stack overflow when handling nested captures

The C code uses recursion to handle nested captures, so a too deep
nesting could create a stack overflow. The fix limits the handling
of nested captures to 'MAXRECLEVEL' (default is 200 levels).

1 files changed, 10 insertions, 0 deletions

diff --git a/test.lua b/test.lua
index 476da0a..8f9f574 100755
--- a/test.lua
+++ b/test.lua
@@ -424,6 +424,16 @@ do
 end
 
 
+do
+  -- nesting of captures too deep
+  local p = m.C(1)
+  for i = 1, 300 do
+    p = m.Ct(p)
+  end
+  checkerr("too deep", p.match, p, "x")
+end
+
+
 -- tests for non-pattern as arguments to pattern functions
 
 p = { ('a' * m.V(1))^-1 } * m.P'b' * { 'a' * m.V(2); m.V(1)^-1 }