vim-patch:8.2.2903: cursor position wrong on wrapped line with 'signcolumn'

Problem:    Cursor position wrong on wrapped line with 'signcolumn'.
Solution:   Don't add space for showbreak twice. (Christian Brabandt,
            closes vim/vim#8262)
a06e345af5

Add a modeline to test_display.vim.

This introduced a regression fixed by v8.2.3391.

src/nvim/screen.c

@@ -3554,6 +3554,13 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool noc
           char_u *p = ptr - (mb_off + 1);
           // TODO: is passing p for start of the line OK?
           n_extra = win_lbr_chartabsize(wp, line, p, (colnr_T)vcol, NULL) - 1;
+
+          // We have just drawn the showbreak value, no need to add
+          // space for it again
+          if (vcol == vcol_sbr) {
+            n_extra -= MB_CHARLEN(get_showbreak_value(wp));
+          }
+
           if (c == TAB && n_extra + col > grid->Columns) {
             n_extra = tabstop_padding(vcol, wp->w_buffer->b_p_ts,
                                       wp->w_buffer->b_p_vts_array) - 1;

src/nvim/testdir/test_display.vim

@@ -262,3 +262,21 @@ func Test_display_scroll_at_topline()
 
   call StopVimInTerminal(buf)
 endfunc
+
+func Test_display_linebreak_breakat()
+  new
+  vert resize 25
+  let _breakat = &breakat
+  setl signcolumn=yes linebreak breakat=) showbreak=+\ 
+  call setline(1, repeat('x', winwidth(0) - 2) .. ')abc')
+  let lines = ScreenLines([1, 2], 25)
+  let expected = [
+          \ '  xxxxxxxxxxxxxxxxxxxxxxx',
+          \ '  + )abc                 '
+          \ ]
+  call assert_equal(expected, lines)
+  %bw!
+  let &breakat=_breakat
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab