Add a failing test for weak arrays

multiple weak arrays on the same value

testsuite/tests/misc/weaklifetime2.ml

@@ -0,0 +1,69 @@
+(*************************************************************************)
+(*                                                                       *)
+(*                                OCaml                                  *)
+(*                                                                       *)
+(*                 Damien Doligez, Jane Street Group, LLC                *)
+(*                                                                       *)
+(*   Copyright 2015 Institut National de Recherche en Informatique et    *)
+(*   en Automatique.  All rights reserved.  This file is distributed     *)
+(*   under the terms of the Q Public License version 1.0.                *)
+(*                                                                       *)
+(*************************************************************************)
+
+let n = 500
+let loop = 2
+
+let alive = ref (Array.init n (fun _ -> Array.make 10 0))
+
+let create_weaks () =
+  Array.init n (fun i ->
+      let w = Weak.create 1 in
+      Weak.set w 0 (Some (!alive.(i)));
+      w
+    )
+
+(** We are trying to keep the weak pointer of weak2 set when the
+    weak pointer of weak1 and weak3 are wrongly unset.
+    [weak1], [weak2] and [weak3] are identical.
+ *)
+
+let weak1 = create_weaks ()
+let weak2 = create_weaks ()
+let weak3 = create_weaks ()
+
+(** put the weak pointers in the major heap *)
+let () =
+  let dummy = ref [||] in
+  for l=0 to 10 do
+    dummy := Array.make 300 0
+  done
+
+let gccount () = (Gc.quick_stat ()).Gc.major_collections;;
+
+let () =
+  for _l=1 to loop do
+    let bad = ref 0 in
+    for i=0 to n-1 do
+      (** make *this* weak key alive *)
+      for _j=0 to n*10 do
+        ignore (Weak.get weak2.(i) 0);
+      done;
+      (** Check that if it is alive in weak2 it is alive in weak1 *)
+      if Weak.check weak2.(i) 0 &&
+         not (Weak.check weak1.(i) 0) &&
+         Weak.check weak2.(i) 0
+      then incr bad;
+      (** Check that if it is alive in weak2 it is alive in weak3
+          This case was failing before the addition of the clean phase in the gc
+      *)
+      if Weak.check weak2.(i) 0 &&
+         not (Weak.check weak3.(i) 0) &&
+         Weak.check weak2.(i) 0
+      then incr bad;
+      !alive.(i) <- Array.make 10 0;
+    done;
+    (* Printf.printf "bad: %i\  gccount:%i\n%!" !bad (gccount ()); *)
+    if !bad > 0
+    then Printf.printf "failing\n%!"
+    else Printf.printf "success\n%!"
+  done

testsuite/tests/misc/weaklifetime2.reference

@@ -0,0 +1,2 @@
+success
+failing