(Fset_buffer_multibyte): Error if marker is put

on buffer's marker-chain while we have temporarily put nil there.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/buffer.c b/src/buffer.c
index e781d25646c..70cb13a9b75 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1822,6 +1822,12 @@ but the contents viewed as characters do change.")
 
           tail = XMARKER (tail)->chain;
         }
+
+      /* Make sure no markers were put on the chain
+         while the chain value was incorrect.  */
+      if (! EQ (BUF_MARKERS (current_buffer), Qnil))
+        abort ();
+
       BUF_MARKERS (current_buffer) = markers;
 
       /* Do this last, so it can calculate the new correspondences