patch 9.0.0893: 'smoothscroll' cursor calculations wrong when 'number' is set

Problem:    'smoothscroll' cursor calculations wrong when 'number' is set.
Solution:   Correct the code that computes the width. (closes #11492)

src/move.c

@@ -1127,13 +1127,15 @@ curs_columns(
 		&& curwin->w_skipcol > 0
 		&& curwin->w_wcol >= curwin->w_skipcol)
 	{
-	    // w_skipcol excludes win_col_off().  Include it here, since w_wcol
+	    // Deduct by multiples of width2.  This allows the long line
-	    // counts actual screen columns.
+	    // wrapping formula below to correctly calculate the w_wcol value
+	    // when wrapping.
 	    if (curwin->w_skipcol <= width1)
-		curwin->w_wcol -= curwin->w_width;
+		curwin->w_wcol -= width2;
 	    else
-		curwin->w_wcol -= curwin->w_width
+		curwin->w_wcol -= width2
 			       * (((curwin->w_skipcol - width1) / width2) + 1);
+
 	    did_sub_skipcol = TRUE;
 	}
 

src/testdir/dumps/Test_smooth_number_7.dump

@@ -1,5 +1,5 @@
-|2+0#af5f00255#ffffff0|<+0#4040ff13&@2|o+0#0000000&|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r|y| |l|o|n>g| |t|e
+|2+0#af5f00255#ffffff0|<+0#4040ff13&@2|o+0#0000000&|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e
-| +0#af5f00255&@3|x+0#0000000&|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r
+| +0#af5f00255&@3>x+0#0000000&|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r
 | +0#af5f00255&@3|y+0#0000000&| |l|o|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g
 | +0#af5f00255&@3| +0#0000000&|t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| |v|e|r|y| |l|o|n|g| |t|e|x|t| 
 | +0#af5f00255&@1|1| |t+0#0000000&|h|r|e@1| @30

src/testdir/test_scroll_opt.vim

@@ -308,5 +308,71 @@ func Test_smoothscroll_one_long_line()
   call StopVimInTerminal(buf)
 endfunc
 
+" Test that if the current cursor is on a smooth scrolled line, we correctly
+" reposition it. Also check that we don't miscalculate the values by checking
+" the consistency between wincol() and col('.') as they are calculated
+" separately in code.
+func Test_smoothscroll_cursor_position()
+  call NewWindow(10, 20)
+  setl smoothscroll wrap
+  call setline(1, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+  func s:check_col_calc(win_col, win_line, buf_col)
+    call assert_equal(a:win_col, wincol())
+    call assert_equal(a:win_line, winline())
+    call assert_equal(a:buf_col, col('.'))
+  endfunc
+
+  call s:check_col_calc(1, 1, 1)
+  exe "normal \<C-E>"
+
+  " Move down another line to avoid blocking the <<< display
+  call s:check_col_calc(1, 2, 41)
+  exe "normal \<C-Y>"
+  call s:check_col_calc(1, 3, 41)
+  normal ggg$
+  exe "normal \<C-E>"
+
+  " Move down only 1 line when we are out of the range of the <<< display
+  call s:check_col_calc(20, 1, 40)
+  exe "normal \<C-Y>"
+  call s:check_col_calc(20, 2, 40)
+  normal gg
+
+  " Test number, where we have indented lines
+  setl number
+  call s:check_col_calc(5, 1, 1)
+  exe "normal \<C-E>"
+  call s:check_col_calc(5, 2, 33)
+  exe "normal \<C-Y>"
+  call s:check_col_calc(5, 3, 33)
+  normal ggg$
+  exe "normal \<C-E>"
+  call s:check_col_calc(20, 1, 32)
+  exe "normal \<C-Y>"
+  call s:check_col_calc(20, 2, 32)
+  normal gg
+
+  " Test number + showbreak, so test that the additional indentation works
+  setl number showbreak=+++
+  call s:check_col_calc(5, 1, 1)
+  exe "normal \<C-E>"
+  call s:check_col_calc(8, 2, 30)
+  exe "normal \<C-Y>"
+  call s:check_col_calc(8, 3, 30)
+  normal gg
+
+  " Test number + cpo+=n mode, where wrapped lines aren't indented
+  setl number cpo+=n showbreak=
+  call s:check_col_calc(5, 1, 1)
+  exe "normal \<C-E>"
+  call s:check_col_calc(1, 2, 37)
+  exe "normal \<C-Y>"
+  call s:check_col_calc(1, 3, 37)
+  normal gg
+
+  bwipeout!
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    893,
 /**/
     892,
 /**/