(widget-specify-field): Don't add a second overlay for a

field with just a newline character.
(widget-field-value-get): Don't reduce fields with just a space
character to null.
(character): Accept newline.  (Bug#2689)

2 files changed, 19 insertions, 4 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index d3978f34feb..886df2dd745 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2009-03-24  Glenn Morris  <rgm@gnu.org>
+
+        * wid-edit.el (widget-specify-field): Don't add a second overlay for a
+        field with just a newline character.
+        (widget-field-value-get): Don't reduce fields with just a space
+        character to null.
+        (character): Accept newline.  (Bug#2689)
+
 2009-03-24  Kenichi Handa  <handa@m17n.org>
 
         * international/fontset.el (font-encoding-alist): Add an entry for
diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index ef89a01e050..5de5f2d9ab5 100644
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -342,12 +342,16 @@ new value.")
          (or (not widget-field-add-space) (widget-get widget :size))))
     (if (functionp help-echo)
       (setq help-echo 'widget-mouse-help))
-    (when (= (char-before to) ?\n)
+    (when (and (> to (1+ from))
+               (= (char-before to) ?\n))
       ;; When the last character in the field is a newline, we want to
       ;; give it a `field' char-property of `boundary', which helps the
       ;; C-n/C-p act more naturally when entering/leaving the field.  We
-     ;; do this by making a small secondary overlay to contain just that
+      ;; do this by making a small secondary overlay to contain just that
       ;; one character.
+      ;; We DON'T do this if the field just consists of a newline, eg
+      ;; when specifying a character, since it breaks things (below
+      ;; does 1- to, which results in to = from).  Bug#2689.
       (let ((overlay (make-overlay (1- to) to nil t nil)))
         (overlay-put overlay 'field 'boundary)
         ;; We need the real field for tabbing.
@@ -1945,7 +1949,9 @@ the earlier input."
           (set-buffer buffer)
           (while (and size
                       (not (zerop size))
-                      (> to from)
+                      ;; Bug#2689.  Don't allow this loop to reduce a
+                      ;; character field to zero size if it contains a space.
+                      (> to (1+ from))
                       (eq (char-after (1- to)) ?\s))
             (setq to (1- to)))
           (let ((result (buffer-substring-no-properties from to)))
@@ -3450,7 +3456,8 @@ To use this type, you must define :match or :match-alternatives."
   :value 0
   :size 1
   :format "%{%t%}: %v\n"
-  :valid-regexp "\\`.\\'"
+  ;; `.' does not match newline, but newline is a valid character.
+  :valid-regexp "\\`\\(.\\|\n\\)\\'"
   :error "This field should contain a single character"
   :value-to-internal (lambda (widget value)
                        (if (stringp value)