From 150271f63fb9f8c7f124d0602f5d12608e9829db Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Thu, 7 Mar 2024 14:50:36 -0500
Subject: [PATCH] declare local OCaml value to the GC in completion bridge

---
 src/linenoise_stubs.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/linenoise_stubs.c b/src/linenoise_stubs.c
index bd8bdb6..28d2bbc 100644
--- a/src/linenoise_stubs.c
+++ b/src/linenoise_stubs.c
@@ -42,11 +42,20 @@ CAMLprim value ml_add_completion(value completions, value new_completion)
   CAMLreturn(Val_unit);
 }
 
+// this bridge runs with the runtime lock acquired
+static void completion_bridge_inner(const char *buf, linenoiseCompletions *lc)
+{
+  CAMLparam0();
+  CAMLlocal1(str_copy);
+  str_copy = caml_copy_string(buf);
+  caml_callback2(*caml_named_value("lnoise_completion_cb"), str_copy, (value)lc);
+  CAMLreturn0;
+}
+
 static void completion_bridge(const char *buf, linenoiseCompletions *lc)
 {
   caml_acquire_runtime_system();
-  value str_copy = caml_copy_string(buf);
-  caml_callback2(*caml_named_value("lnoise_completion_cb"), str_copy, (value)lc);
+  completion_bridge_inner(buf, lc);
   caml_release_runtime_system();
 }