* lisp/vc/smerge-mode.el (smerge-refine): Choose better default part to

highlight when one of them is empty.

2 files changed, 7 insertions, 0 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 64c52eebc7b..4b1e880e547 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,8 @@
 2010-11-12  Stefan Monnier  <monnier@iro.umontreal.ca>
 
+        * vc/smerge-mode.el (smerge-refine): Choose better default part to
+        highlight when one of them is empty.
+
         * skeleton.el (skeleton-read): Don't use `newline' since it may strip
         trailing space.
         (skeleton-newline): New function.
diff --git a/lisp/vc/smerge-mode.el b/lisp/vc/smerge-mode.el
index 6e72071b6a0..32f829f814e 100644
--- a/lisp/vc/smerge-mode.el
+++ b/lisp/vc/smerge-mode.el
@@ -1009,6 +1009,10 @@ repeating the command will highlight other two parts."
   (setq part (cond ((null (match-end 2)) 2)
                    ((eq (match-end 1) (match-end 3)) 1)
                    ((integerp part) part)
+                   ;; If one of the parts is empty, any refinement using
+                   ;; it will be trivial and uninteresting.
+                   ((eq (match-end 1) (match-beginning 1)) 1)
+                   ((eq (match-end 3) (match-beginning 3)) 3)
                    (t 2)))
   (let ((n1 (if (eq part 1) 2 1))
         (n2 (if (eq part 3) 2 3)))