Fix bug #17942 with pos-visible-in-window-p and image and BOB.

 src/xdisp.c (pos_visible_p): If CHARPOS is at BEGV, and there is a
 display property at BEGV, don't call move_it_to to move to a
 position before BEGV.

2 files changed, 8 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 6048522cdc4..dde148dc165 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2014-07-05  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (pos_visible_p): If CHARPOS is at BEGV, and there is a
+        display property at BEGV, don't call move_it_to to move to a
+        position before BEGV.  (Bug#17942)
+
 2014-07-05  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * syntax.c (find_defun_start): Try the cache even
diff --git a/src/xdisp.c b/src/xdisp.c
index fe5d0f579d8..f5ddf828314 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -1585,7 +1585,8 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int *x, int *y,
                   /* Move to the last buffer position before the
                      display property.  */
                   start_display (&it3, w, top);
-                  move_it_to (&it3, start - 1, -1, -1, -1, MOVE_TO_POS);
+                  if (start > BEGV)
+                    move_it_to (&it3, start - 1, -1, -1, -1, MOVE_TO_POS);
                   /* Move forward one more line if the position before
                      the display string is a newline or if it is the
                      rightmost character on a line that is