patch 9.0.1568: with 'smoothscroll' cursor may move below botlinev9.0.1568

Problem:    With 'smoothscroll' cursor may move below botline.
Solution:   Call redraw_later() if needed,  Compute cursor row with adjusted
            condition. (Luuk van Baal, closes #12415)

9 files changed, 75 insertions, 9 deletions

diff --git a/src/move.c b/src/move.c
index 3f6802ac7f..e435bb08bb 100644
--- a/src/move.c
+++ b/src/move.c
@@ -519,6 +519,8 @@ update_topline(void)
 	// When 'smoothscroll' is not set, should reset w_skipcol.
 	if (!curwin->w_p_sms)
 	    reset_skipcol();
+	else if (curwin->w_skipcol != 0)
+	    redraw_later(UPD_SOME_VALID);
 
 	// May need to set w_skipcol when cursor in w_topline.
 	if (curwin->w_cursor.lnum == curwin->w_topline)
@@ -892,10 +894,11 @@ curs_rows(win_T *wp)
 		--i;			// hold at inserted lines
 	}
 	if (valid
+	       && (lnum != wp->w_topline || (wp->w_skipcol == 0
 #ifdef FEAT_DIFF
-		&& (lnum != wp->w_topline || !wp->w_p_diff)
+					    && !wp->w_p_diff
 #endif
-		)
+	       )))
 	{
 #ifdef FEAT_FOLDING
 	    lnum = wp->w_lines[i].wl_lastlnum + 1;
diff --git a/src/testdir/dumps/Test_smooth_incsearch_1.dump b/src/testdir/dumps/Test_smooth_incsearch_1.dump
new file mode 100644
index 0000000000..830b855d1d
--- /dev/null
+++ b/src/testdir/dumps/Test_smooth_incsearch_1.dump
@@ -0,0 +1,8 @@
+|<+0#4040ff13#ffffff0@2| +0#af5f00255&|a+0#0000000&@27| @7
+| +0#af5f00255&|1|2| | +0#0000000&@35
+| +0#af5f00255&|1|3| | +0#0000000&@35
+| +0#af5f00255&|1|4| |b+1#0000000&|b+0&&@2| @31
+| +0#af5f00255&|1|5| | +0#0000000&@35
+| +0#af5f00255&|1|6| | +0#0000000&@35
+| +0#af5f00255&|1|7| | +0#0000000&@35
+|/|b> @37
diff --git a/src/testdir/dumps/Test_smooth_incsearch_2.dump b/src/testdir/dumps/Test_smooth_incsearch_2.dump
new file mode 100644
index 0000000000..349e12861b
--- /dev/null
+++ b/src/testdir/dumps/Test_smooth_incsearch_2.dump
@@ -0,0 +1,8 @@
+|<+0#4040ff13#ffffff0@2| +0#af5f00255&|a+0#0000000&@27| @7
+| +0#af5f00255&|1|2| | +0#0000000&@35
+| +0#af5f00255&|1|3| | +0#0000000&@35
+| +0#af5f00255&|1|4| |b+1#0000000&@1|b+0&&@1| @31
+| +0#af5f00255&|1|5| | +0#0000000&@35
+| +0#af5f00255&|1|6| | +0#0000000&@35
+| +0#af5f00255&|1|7| | +0#0000000&@35
+|/|b@1> @36
diff --git a/src/testdir/dumps/Test_smooth_incsearch_3.dump b/src/testdir/dumps/Test_smooth_incsearch_3.dump
new file mode 100644
index 0000000000..0be3d21932
--- /dev/null
+++ b/src/testdir/dumps/Test_smooth_incsearch_3.dump
@@ -0,0 +1,8 @@
+|<+0#4040ff13#ffffff0@2| +0#af5f00255&|a+0#0000000&@27| @7
+| +0#af5f00255&|1|2| | +0#0000000&@35
+| +0#af5f00255&|1|3| | +0#0000000&@35
+| +0#af5f00255&|1|4| |b+1#0000000&@2|b+0&&| @31
+| +0#af5f00255&|1|5| | +0#0000000&@35
+| +0#af5f00255&|1|6| | +0#0000000&@35
+| +0#af5f00255&|1|7| | +0#0000000&@35
+|/|b@2> @35
diff --git a/src/testdir/dumps/Test_smooth_incsearch_4.dump b/src/testdir/dumps/Test_smooth_incsearch_4.dump
new file mode 100644
index 0000000000..c81c24b407
--- /dev/null
+++ b/src/testdir/dumps/Test_smooth_incsearch_4.dump
@@ -0,0 +1,8 @@
+|<+0#4040ff13#ffffff0@2| +0#af5f00255&|a+0#0000000&@27| @7
+| +0#af5f00255&|1|2| | +0#0000000&@35
+| +0#af5f00255&|1|3| | +0#0000000&@35
+| +0#af5f00255&|1|4| |b+1#0000000&@3| +0&&@31
+| +0#af5f00255&|1|5| | +0#0000000&@35
+| +0#af5f00255&|1|6| | +0#0000000&@35
+| +0#af5f00255&|1|7| | +0#0000000&@35
+|/|b@3> @34
diff --git a/src/testdir/dumps/Test_smooth_wrap_2.dump b/src/testdir/dumps/Test_smooth_wrap_2.dump
index fb0a981a8d..65a357dbb1 100644
--- a/src/testdir/dumps/Test_smooth_wrap_2.dump
+++ b/src/testdir/dumps/Test_smooth_wrap_2.dump
@@ -1,8 +1,8 @@
-|L+0&#ffffff0|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
+|<+0#4040ff13#ffffff0@2|h+0#0000000&| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
+|L|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
 |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| 
 |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
 >L|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
 |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| 
 |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
-|@+0#4040ff13&@2| @36
-| +0#0000000&@21|4|,|1| @10|4|0|%| 
+@22|4|,|1| @10|2|5|%| 
diff --git a/src/testdir/dumps/Test_smooth_wrap_4.dump b/src/testdir/dumps/Test_smooth_wrap_4.dump
index 1c42f64f48..c23f494dcd 100644
--- a/src/testdir/dumps/Test_smooth_wrap_4.dump
+++ b/src/testdir/dumps/Test_smooth_wrap_4.dump
@@ -2,7 +2,7 @@
 |L|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
 |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| 
 |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
-|L|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
+>L|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
 |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| 
->w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
+|w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
 @22|7|,|1| @10|B|o|t| 
diff --git a/src/testdir/test_scroll_opt.vim b/src/testdir/test_scroll_opt.vim
index 469cf12719..648060bd58 100644
--- a/src/testdir/test_scroll_opt.vim
+++ b/src/testdir/test_scroll_opt.vim
@@ -257,11 +257,14 @@ func Test_smoothscroll_wrap_scrolloff_zero()
   call term_sendkeys(buf, "G")
   call VerifyScreenDump(buf, 'Test_smooth_wrap_4', {})
 
-  " moving cursor up right after the >>> marker - no need to show whole line
+  call term_sendkeys(buf, "4\<C-Y>G")
+  call VerifyScreenDump(buf, 'Test_smooth_wrap_4', {})
+
+  " moving cursor up right after the <<< marker - no need to show whole line
   call term_sendkeys(buf, "2gj3l2k")
   call VerifyScreenDump(buf, 'Test_smooth_wrap_5', {})
 
-  " moving cursor up where the >>> marker is - whole top line shows
+  " moving cursor up where the <<< marker is - whole top line shows
   call term_sendkeys(buf, "2j02k")
   call VerifyScreenDump(buf, 'Test_smooth_wrap_6', {})
 
@@ -705,4 +708,30 @@ func Test_smoothscroll_eob()
   call StopVimInTerminal(buf)
 endfunc
 
+" skipcol should not reset when doing incremental search on the same word
+func Test_smoothscroll_incsearch()
+  CheckScreendump
+
+  let lines =<< trim END
+      set smoothscroll number scrolloff=0 incsearch
+      call setline(1, repeat([''], 20))
+      call setline(11, repeat('a', 100))
+      call setline(14, 'bbbb')
+  END
+  call writefile(lines, 'XSmoothIncsearch', 'D')
+  let buf = RunVimInTerminal('-S XSmoothIncsearch', #{rows: 8, cols:40})
+
+  call term_sendkeys(buf, "/b")
+  call VerifyScreenDump(buf, 'Test_smooth_incsearch_1', {})
+  call term_sendkeys(buf, "b")
+  call VerifyScreenDump(buf, 'Test_smooth_incsearch_2', {})
+  call term_sendkeys(buf, "b")
+  call VerifyScreenDump(buf, 'Test_smooth_incsearch_3', {})
+  call term_sendkeys(buf, "b")
+  call VerifyScreenDump(buf, 'Test_smooth_incsearch_4', {})
+  call term_sendkeys(buf, "\<CR>")
+
+  call StopVimInTerminal(buf)
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index 42c2c0faed..54d927e05e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1568,
+/**/
     1567,
 /**/
     1566,