Fix bug #17986 with infloop in redisplay when default-directory is nil.

 src/xdisp.c (decode_mode_spec): Call file-remote-p on the current
 buffer's default-directory only if it is a string.

 lisp/bindings.el (mode-line-remote): If default-directory is not a
 string, don't call file-remote-p on it; instead state in the
 help-echo that it is nil.

2 files changed, 11 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9051d37fcef..ca31b10fb6a 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2014-07-13  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (decode_mode_spec): Call file-remote-p on the current
+        buffer's default-directory only if it is a string.  (Bug#17986)
+
 2014-07-12  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (display_line): Don't call FETCH_BYTE with argument less
diff --git a/src/xdisp.c b/src/xdisp.c
index 6918c4360d4..2f0683294fa 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -22907,8 +22907,12 @@ decode_mode_spec (struct window *w, register int c, int field_width,
     case '@':
       {
         ptrdiff_t count = inhibit_garbage_collection ();
-        Lisp_Object val = call1 (intern ("file-remote-p"),
-                                 BVAR (current_buffer, directory));
+        Lisp_Object curdir = BVAR (current_buffer, directory);
+        Lisp_Object val = Qnil;
+
+        if (STRINGP (curdir))
+          val = call1 (intern ("file-remote-p"), curdir);
+
         unbind_to (count, Qnil);
 
         if (NILP (val))