# HG changeset patch
# User Bram Moolenaar <Bram@vim.org>
# Date 1557664208 -7200
# Node ID 06fd0eaada01b50341fd72493661f330e127875c
# Parent  5d15f9774fda2c717bc3904440ba223df5ed7d90
patch 8.1.1327: unnecessary scroll after horizontal split

commit https://github.com/vim/vim/commit/a9b2535f44f3265940a18d08520a9ad4ef7bda82
Author: Bram Moolenaar <Bram@vim.org>
Date:   Sun May 12 14:25:30 2019 +0200

    patch 8.1.1327: unnecessary scroll after horizontal split

    Problem:    Unnecessary scroll after horizontal split.
    Solution:   Don't adjust to fraction if all the text fits in the window.
                (Martin Kunev, closes #4367)

diff --git a/src/testdir/test_window_cmd.vim b/src/testdir/test_window_cmd.vim
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -743,6 +743,42 @@ func Test_relative_cursor_second_line_af
   let &so = so_save
 endfunc
 
+func Test_split_noscroll()
+  let so_save = &so
+  new
+  only
+
+  " Make sure windows can hold all content after split.
+  for i in range(1, 20)
+    wincmd +
+    redraw!
+  endfor
+
+  call setline (1, range(1, 8))
+  normal 100%
+  split
+
+  1wincmd w
+  let winid1 = win_getid()
+  let info1 = getwininfo(winid1)[0]
+
+  2wincmd w
+  let winid2 = win_getid()
+  let info2 = getwininfo(winid2)[0]
+
+  call assert_equal(1, info1.topline)
+  call assert_equal(1, info2.topline)
+
+  " Restore original state.
+  for i in range(1, 20)
+    wincmd -
+    redraw!
+  endfor
+  only!
+  bwipe!
+  let &so = so_save
+endfunc
+
 " Tests for the winnr() function
 func Test_winnr()
   only | tabonly
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1327,
+/**/
     1326,
 /**/
     1325,
diff --git a/src/window.c b/src/window.c
--- a/src/window.c
+++ b/src/window.c
@@ -5827,9 +5827,13 @@ scroll_to_fraction(win_T *wp, int prev_h
     int		sline, line_size;
     int		height = wp->w_height;
 
-    // Don't change w_topline when height is zero.  Don't set w_topline when
-    // 'scrollbind' is set and this isn't the current window.
-    if (height > 0 && (!wp->w_p_scb || wp == curwin))
+    // Don't change w_topline in any of these cases:
+    // - window height is 0
+    // - 'scrollbind' is set and this isn't the current window
+    // - window height is sufficient to display the whole buffer
+    if (height > 0
+        && (!wp->w_p_scb || wp == curwin)
+        && (height < wp->w_buffer->b_ml.ml_line_count))
     {
 	/*
 	 * Find a value for w_topline that shows the cursor at the same