Tweak updating the process mark in set-process-buffer

* src/process.c (Fset_process_buffer): Only update the process
mark if we actually change the buffer.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/process.c b/src/process.c
index ee8dcbbf749..50c425077a9 100644
--- a/src/process.c
+++ b/src/process.c
@@ -1227,11 +1227,14 @@ Return BUFFER.  */)
   if (!NILP (buffer))
     CHECK_BUFFER (buffer);
   p = XPROCESS (process);
-  pset_buffer (p, buffer);
+  if (!EQ (p->buffer, buffer))
+    {
+      pset_buffer (p, buffer);
+      update_process_mark (p);
+    }
   if (NETCONN1_P (p) || SERIALCONN1_P (p) || PIPECONN1_P (p))
     pset_childp (p, Fplist_put (p->childp, QCbuffer, buffer));
   setup_process_coding_systems (process);
-  update_process_mark (p);
   return buffer;
 }