From 72fbb05ee895896e7a2a82806637ad92d80b5eaf Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 16 May 2025 22:38:45 +0200
Subject: [PATCH] Fix Guile's whippet embedding for conservative roots tracing

* libguile/whippet-embedder.h (gc_extern_space_visit): Don't crash if
conservative tracing is enabled: these are already part of the root set.
---
 libguile/whippet-embedder.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libguile/whippet-embedder.h b/libguile/whippet-embedder.h
index 82e177936..c2b993c01 100644
--- a/libguile/whippet-embedder.h
+++ b/libguile/whippet-embedder.h
@@ -65,7 +65,11 @@ gc_is_valid_conservative_ref_displacement (uintptr_t displacement) {
 static inline int gc_extern_space_visit (struct gc_extern_space *space,
                                          struct gc_edge edge,
                                          struct gc_ref ref) {
+#if GC_CONSERVATIVE_TRACE
+  return 0;
+#else
   GC_CRASH ();
+#endif
 }
 static inline void gc_extern_space_start_gc (struct gc_extern_space *space,
                                              int is_minor_gc) {