From 598677b6ccddfc25735305c6d325996d6ed80f18 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20H=C3=B6gberg?= <john@erlang.org>
Date: Tue, 23 Apr 2019 10:35:53 +0200
Subject: [PATCH] fixup! fixup! Use an array for the position stack rather than
 an Erlang list

---
 c_src/termstack.c              | 6 +++++-
 test/jiffy_06_object_tests.erl | 8 ++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/c_src/termstack.c b/c_src/termstack.c
index 7bce38f..95c5b95 100644
--- a/c_src/termstack.c
+++ b/c_src/termstack.c
@@ -15,7 +15,11 @@ termstack_push(TermStack *stack, ERL_NIF_TERM term)
         size_t new_size = stack->size * 2;
 
         if (stack->elements == &stack->__default_elements[0]) {
-            stack->elements = enif_alloc(new_size * sizeof(ERL_NIF_TERM));
+            ERL_NIF_TERM *new_elements = enif_alloc(new_size * sizeof(ERL_NIF_TERM));
+
+            memcpy(new_elements, stack->elements, stack->size * sizeof(ERL_NIF_TERM));
+
+            stack->elements = new_elements;
         } else {
             stack->elements = enif_realloc(stack->elements,
                                            new_size * sizeof(ERL_NIF_TERM));
diff --git a/test/jiffy_06_object_tests.erl b/test/jiffy_06_object_tests.erl
index 9a8f4fb..1baacbf 100644
--- a/test/jiffy_06_object_tests.erl
+++ b/test/jiffy_06_object_tests.erl
@@ -20,6 +20,14 @@ latin1_atom_test_() ->
     Expected = <<"{\"", 195, 164, "\":\"bar\"}">>,
     ?_assertEqual(Expected, enc(#{ Key => <<"bar">> })).
 
+nested_object_segv_test_() ->
+    Obj = nested(128),
+    Enc = enc(Obj),
+    ?_assertEqual(Obj, dec(Enc)).
+
+nested(0) -> <<"bottom">>;
+nested(N) -> {[{integer_to_binary(N), nested(N - 1)}]}.
+
 gen(ok, {J, E}) ->
     gen(ok, {J, E, J});
 gen(ok, {J1, E, J2}) ->