(store_symval_forwarding): Handle setting default-fill-column, etc.,

by changing buffers that use the default.

1 files changed, 32 insertions, 0 deletions

diff --git a/src/data.c b/src/data.c
index a246271c1f6..c4e3937f3fa 100644
--- a/src/data.c
+++ b/src/data.c
@@ -873,6 +873,8 @@ store_symval_forwarding (symbol, valcontents, newval, buf)
      register Lisp_Object valcontents, newval;
      struct buffer *buf;
 {
+  int offset;
+
   switch (SWITCH_ENUM_CAST (XTYPE (valcontents)))
     {
     case Lisp_Misc:
@@ -892,6 +894,36 @@ store_symval_forwarding (symbol, valcontents, newval, buf)
 
         case Lisp_Misc_Objfwd:
           *XOBJFWD (valcontents)->objvar = newval;
+
+          /* If this variable is a default for something stored
+             in the buffer itself, such as default-fill-column,
+             find the buffers that don't have local values for it
+             and update them.  */
+          if (XOBJFWD (valcontents)->objvar > (Lisp_Object *) &buffer_defaults
+              && XOBJFWD (valcontents)->objvar < (Lisp_Object *) (&buffer_defaults + 1))
+            {
+              int offset = ((char *) XOBJFWD (valcontents)->objvar
+                            - (char *) &buffer_defaults);
+              int idx = PER_BUFFER_IDX (offset);
+
+              Lisp_Object tail, buf;
+
+              if (idx <= 0)
+                break;
+
+              for (tail = Vbuffer_alist; CONSP (tail); tail = XCDR (tail))
+                {
+                  Lisp_Object buf;
+                  struct buffer *b;
+
+                  buf = Fcdr (XCAR (tail));
+                  if (!BUFFERP (buf)) continue;
+                  b = XBUFFER (buf);
+
+                  if (! PER_BUFFER_VALUE_P (b, idx))
+                    PER_BUFFER_VALUE (b, offset) = newval;
+                }
+            }
           break;
 
         case Lisp_Misc_Buffer_Objfwd: