# HG changeset patch
# User Christian Brabandt <cb@256bit.org>
# Date 1712940307 -7200
# Node ID 4e6b29ea6ed2c19bd20b2af38d03c288411f75e3
# Parent  56f77a6b54aa7bfb1d326041c3e30cd499474b3c
patch 9.1.0310: Filler lines not checked properly in get_scroll_overlap()

Commit: https://github.com/vim/vim/commit/92325540876252eb7375e34ff8f92cd4265fa7ae
Author: zeertzjq <zeertzjq@outlook.com>
Date:   Fri Apr 12 18:38:38 2024 +0200

    patch 9.1.0310: Filler lines not checked properly in get_scroll_overlap()

    Problem:  Filler lines not checked properly in get_scroll_overlap().
    Solution: Add missing parentheses (zeertzjq).

    The missing parentheses causes the second argument to diff_check_fill()
    to always be 0 as it is the result of a comparison between a positive
    integer and -1 (the value of BACKWARD), in which case diff_check_fill()
    always returns 0 instead of the number of filler lines above a line.

    It's very hard to add a test for this, because this mistake at most
    leads to 2 screen lines of difference in scrolling behavior, and in
    cases where it may indeed lead to a difference in behavior, neither
    behavior achieves complete symmetry between CTRL-F and CTRL-B.

    closes: #14527

    Signed-off-by: zeertzjq <zeertzjq@outlook.com>
    Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/src/move.c b/src/move.c
--- a/src/move.c
+++ b/src/move.c
@@ -3102,7 +3102,7 @@ static int get_scroll_overlap(int dir)
 
     loff.lnum = dir == FORWARD ? curwin->w_botline : curwin->w_topline - 1;
 #ifdef FEAT_DIFF
-    loff.fill = diff_check_fill(curwin, loff.lnum + dir == BACKWARD)
+    loff.fill = diff_check_fill(curwin, loff.lnum + (dir == BACKWARD))
 		- (dir == FORWARD ? curwin->w_filler_rows : curwin->w_topfill);
     loff.height = loff.fill > 0 ? 1 : plines_nofill(loff.lnum);
 #else
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    310,
+/**/
     309,
 /**/
     308,