* src/indent.c (Fvertical_motion): Amend motion by 0 lines.

Starting from a display string after a newline, point went to the
previous line.  Also, fix an inadvertent use of a buffer position
with FETCH_BYTE.  (Bug#20701)

diff --git a/src/indent.c b/src/indent.c
index ce78308c95b0af82654ae5647678d3f082a38dcb..b4e6d7454999af05c26ad0b577f81dd22816055f 100644 (file)
--- a/src/indent.c
+++ b/src/indent.c
@@ -2134,17 +2134,20 @@ whether or not it is currently displayed in some window.  */)
          overshoot_handled = 1;
        }
       else if (IT_CHARPOS (it) == PT - 1
-              && FETCH_BYTE (PT - 1) == '\n'
-              && nlines < 0)
+              && FETCH_BYTE (PT_BYTE - 1) == '\n'
+              && nlines <= 0)
        {
          /* The position we started from was covered by a display
             property, so we moved to position before the string, and
-            backed up one line, because the character at PT - 1 is a
-            newline.  So we need one less line to go up.  */
+            backed up one line, because the character at PT - 1 is
+            a newline.  So we need one less line to go up (or exactly
+            one line to go down if nlines == 0).  */
          nlines++;
          /* But we still need to record that one line, in order to
             return the correct value to the caller.  */
          vpos_init = -1;
+
+         overshoot_handled = 1;
        }
       if (lcols_given)
        to_x = window_column_x (w, window, extract_float (lcols), lcols);
@@ -2159,7 +2162,7 @@ whether or not it is currently displayed in some window.  */)
        }
       else if (overshoot_handled)
        {
-         it.vpos = 0;
+         it.vpos = vpos_init;
          move_it_by_lines (&it, min (PTRDIFF_MAX, nlines));
        }
       else