Fix bug #15712 with vertical motion when the goal column needs to hscroll.

 lisp/simple.el (line-move): Call line-move-1 instead of
 line-move-visual when the current window hscroll is zero, but
 temporary-goal-column indicates we will need to hscroll as result
 of the movement.

2 files changed, 17 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 07de60c735d..c7da1c86416 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,10 @@
+2013-10-25  Eli Zaretskii  <eliz@gnu.org>
+
+        * simple.el (line-move): Call line-move-1 instead of
+        line-move-visual when the current window hscroll is zero, but
+        temporary-goal-column indicates we will need to hscroll as result
+        of the movement.  (Bug#15712)
+
 2013-10-25  Dmitry Gutov  <dgutov@yandex.ru>
 
         * progmodes/ruby-mode.el (ruby-mode-menu): Use proper
diff --git a/lisp/simple.el b/lisp/simple.el
index 3fefce15d2a..1f1b5cb376f 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -4908,7 +4908,16 @@ The value is a floating-point number."
                ;; When the text in the window is scrolled to the left,
                ;; display-based motion doesn't make sense (because each
                ;; logical line occupies exactly one screen line).
-               (not (> (window-hscroll) 0)))
+               (not (> (window-hscroll) 0))
+               ;; Likewise when the text _was_ scrolled to the left
+               ;; when the current run of vertical motion commands
+               ;; started.
+               (not (and (memq last-command
+                               `(next-line previous-line ,this-command))
+                         auto-hscroll-mode
+                         (numberp temporary-goal-column)
+                         (>= temporary-goal-column
+                            (- (window-width) hscroll-margin)))))
           (prog1 (line-move-visual arg noerror)
             ;; If we moved into a tall line, set vscroll to make
             ;; scrolling through tall images more smooth.