vim-patch:9.0.1783: Display issues with virt text smoothscroll and showbreak

Problem:  Wrong display with wrapping virtual text or unprintable chars,
          'showbreak' and 'smoothscroll'.
Solution: Don't skip cells taken by 'showbreak' in screen lines before
          "w_skipcol". Combined "n_skip" and "skip_cells".

closes: vim/vim#12597

https://github.com/vim/vim/commit/b557f4898208105b674df605403cac1b1292707b

8 files changed, 557 insertions, 88 deletions

diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index 4030d818c8..d11cbddccf 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -991,6 +991,7 @@ void getvcol(win_T *wp, pos_T *pos, colnr_T *start, colnr_T *cursor, colnr_T *en
   chartabsize_T cts;
   bool on_NUL = false;
   init_chartabsize_arg(&cts, wp, pos->lnum, 0, line, line);
+  cts.cts_max_head_vcol = -1;
 
   // This function is used very often, do some speed optimizations.
   // When 'list', 'linebreak', 'showbreak' and 'breakindent' are not set
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 753baa2675..fa2aecff86 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -132,9 +132,12 @@ typedef struct {
 
   bool reset_extra_attr;
 
-  int skip_cells;                   // nr of cells to skip for virtual text
-  int skipped_cells;                // nr of skipped virtual text cells
-  bool more_virt_inline_chunks;     // indicates if there is more inline virtual text after n_extra
+  int skip_cells;            ///< nr of cells to skip for w_leftcol
+                             ///< or w_skipcol or concealing
+  int skipped_cells;         ///< nr of skipped cells for virtual text
+                             ///< to be added to wlv.vcol later
+  bool more_virt_inline_chunks;  ///< indicates if there is more inline virtual text
+                                 ///< after n_extra
 } winlinevars_T;
 
 /// for line_putchar. Contains the state that needs to be remembered from
@@ -1090,9 +1093,6 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
   int n_attr3 = 0;                      // chars with overruling special attr
   int saved_attr3 = 0;                  // char_attr saved for n_attr3
 
-  int n_skip = 0;                       // nr of chars to skip for 'nowrap' or
-                                        // concealing
-
   int fromcol_prev = -2;                // start of inverting after cursor
   bool noinvcur = false;                // don't invert the cursor
   bool lnum_in_visual_area = false;
@@ -1500,10 +1500,13 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
     char *prev_ptr = ptr;
     chartabsize_T cts;
     int charsize = 0;
+    int head = 0;
 
     init_chartabsize_arg(&cts, wp, lnum, wlv.vcol, line, ptr);
+    cts.cts_max_head_vcol = (int)v;
     while (cts.cts_vcol < v && *cts.cts_ptr != NUL) {
-      charsize = win_lbr_chartabsize(&cts, NULL);
+      head = 0;
+      charsize = win_lbr_chartabsize(&cts, &head);
       cts.cts_vcol += charsize;
       prev_ptr = cts.cts_ptr;
       MB_PTR_ADV(cts.cts_ptr);
@@ -1530,17 +1533,10 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
     if (wlv.vcol > v) {
       wlv.vcol -= charsize;
       ptr = prev_ptr;
-      // If the character fits on the screen, don't need to skip it.
-      // Except for a TAB.
-      if (utf_ptr2cells(ptr) >= charsize || *ptr == TAB) {
-        n_skip = (int)(v - wlv.vcol);
-      }
     }
 
-    // If there the text doesn't reach to the desired column, need to skip
-    // "skip_cells" cells when virtual text follows.
-    if ((!wp->w_p_wrap || (lnum == wp->w_topline && wp->w_skipcol > 0)) && v > wlv.vcol) {
-      wlv.skip_cells = (int)(v - wlv.vcol);
+    if (v > wlv.vcol) {
+      wlv.skip_cells = (int)v - wlv.vcol - head;
     }
 
     // Adjust for when the inverted text is before the screen,
@@ -1808,9 +1804,6 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
             decor_attr = 0;
             search_attr_from_match = false;
           }
-          if (wlv.n_extra > 0) {
-            n_skip = 0;
-          }
         }
       }
 
@@ -2027,6 +2020,12 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
       // Get a character from the line itself.
       c0 = c = (uint8_t)(*ptr);
       mb_c = c;
+
+      if (c == NUL) {
+        // no more cells to skip
+        wlv.skip_cells = 0;
+      }
+
       // If the UTF-8 character is more than one byte: Decode it
       // into "mb_c".
       mb_l = utfc_ptr2len(ptr);
@@ -2118,7 +2117,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
 
       // If a double-width char doesn't fit at the left side display a '<' in
       // the first column.  Don't do this for unprintable characters.
-      if (n_skip > 0 && mb_l > 1 && wlv.n_extra == 0) {
+      if (wlv.skip_cells > 0 && mb_l > 1 && wlv.n_extra == 0) {
         wlv.n_extra = 1;
         wlv.c_extra = MB_FILLER_CHAR;
         wlv.c_final = NUL;
@@ -2619,9 +2618,9 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
           }
           wlv.n_extra = 0;
           wlv.n_attr = 0;
-        } else if (n_skip == 0) {
+        } else if (wlv.skip_cells == 0) {
           is_concealing = true;
-          n_skip = 1;
+          wlv.skip_cells = 1;
         }
         mb_c = c;
         mb_utf8 = check_mb_utf8(&c, u8cc);
@@ -2630,7 +2629,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
         is_concealing = false;
       }
 
-      if (n_skip > 0 && did_decrement_ptr) {
+      if (wlv.skip_cells > 0 && did_decrement_ptr) {
         // not showing the '>', put pointer back to avoid getting stuck
         ptr++;
       }
@@ -2641,7 +2640,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
     if (!did_wcol && wlv.draw_state == WL_LINE
         && wp == curwin && lnum == wp->w_cursor.lnum
         && conceal_cursor_line(wp)
-        && (int)wp->w_virtcol <= wlv.vcol + n_skip) {
+        && (int)wp->w_virtcol <= wlv.vcol + wlv.skip_cells) {
       if (wp->w_p_rl) {
         wp->w_wcol = grid->cols - wlv.col + wlv.boguscols - 1;
       } else {
@@ -2946,7 +2945,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
 
     // Store character to be displayed.
     // Skip characters that are left of the screen for 'nowrap'.
-    if (wlv.draw_state < WL_LINE || n_skip <= 0) {
+    if (wlv.draw_state < WL_LINE || wlv.skip_cells <= 0) {
       // Store the character.
       if (wp->w_p_rl && utf_char2cells(mb_c) > 1) {
         // A double-wide character is: put first half in left cell.
@@ -2999,7 +2998,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
         wlv.col++;
       }
     } else if (wp->w_p_cole > 0 && is_concealing) {
-      n_skip--;
+      wlv.skip_cells--;
       wlv.vcol_off++;
       if (wlv.n_extra > 0) {
         wlv.vcol_off += wlv.n_extra;
@@ -3055,7 +3054,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool number_onl
         }
       }
     } else {
-      n_skip--;
+      wlv.skip_cells--;
     }
 
     // The skipped cells need to be accounted for in vcol.
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 915399ec78..869b226856 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -232,7 +232,8 @@ static void insert_enter(InsertState *s)
   may_trigger_modechanged();
   stop_insert_mode = false;
 
-  // need to position cursor again when on a TAB
+  // need to position cursor again when on a TAB and
+  // when on a char with inline virtual text
   if (gchar_cursor() == TAB || curbuf->b_virt_text_inline > 0) {
     curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
   }
@@ -3471,7 +3472,8 @@ static bool ins_esc(long *count, int cmdchar, bool nomove)
 
   State = MODE_NORMAL;
   may_trigger_modechanged();
-  // need to position cursor again when on a TAB
+  // need to position cursor again when on a TAB and
+  // when on a char with inline virtual text
   if (gchar_cursor() == TAB || curbuf->b_virt_text_inline > 0) {
     curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
   }
diff --git a/src/nvim/plines.c b/src/nvim/plines.c
index 431e4cd8c9..ab4a12cd89 100644
--- a/src/nvim/plines.c
+++ b/src/nvim/plines.c
@@ -369,16 +369,19 @@ int lbr_chartabsize_adv(chartabsize_T *cts)
   return retval;
 }
 
+/// Get the number of characters taken up on the screen indicated by "cts".
+/// "cts->cts_cur_text_width_left" and "cts->cts_cur_text_width_right" are set
+/// to the extra size for inline virtual text.
 /// This function is used very often, keep it fast!!!!
 ///
-/// If "headp" not NULL, set *headp to the size of what we for 'showbreak'
-/// string at start of line.  Warning: *headp is only set if it's a non-zero
-/// value, init to 0 before calling.
+/// If "headp" not NULL, set "*headp" to the size of 'showbreak'/'breakindent'
+/// included in the return value.
+/// When "cts->cts_max_head_vcol" is positive, only count in "*headp" the size
+/// of 'showbreak'/'breakindent' before "cts->cts_max_head_vcol".
+/// When "cts->cts_max_head_vcol" is negative, only count in "*headp" the size
+/// of 'showbreak'/'breakindent' before where cursor should be placed.
 ///
-/// @param cts
-/// @param headp
-///
-/// @return The number of characters taken up on the screen.
+/// Warning: "*headp" may not be set if it's 0, init to 0 before calling.
 int win_lbr_chartabsize(chartabsize_T *cts, int *headp)
 {
   win_T *wp = cts->cts_win;
@@ -388,7 +391,6 @@ int win_lbr_chartabsize(chartabsize_T *cts, int *headp)
 
   colnr_T col_adj = 0;  // vcol + screen size of tab
   int mb_added = 0;
-  int numberextra;
 
   cts->cts_cur_text_width_left = 0;
   cts->cts_cur_text_width_right = 0;
@@ -449,7 +451,7 @@ int win_lbr_chartabsize(chartabsize_T *cts, int *headp)
       && (wp->w_width_inner != 0)) {
     // Count all characters from first non-blank after a blank up to next
     // non-blank after a blank.
-    numberextra = win_col_off(wp);
+    int numberextra = win_col_off(wp);
     colnr_T col2 = vcol;
     colnr_T colmax = (colnr_T)(wp->w_width_inner - numberextra - col_adj);
 
@@ -490,72 +492,92 @@ int win_lbr_chartabsize(chartabsize_T *cts, int *headp)
 
   // May have to add something for 'breakindent' and/or 'showbreak'
   // string at start of line.
-  // Set *headp to the size of what we add.
   // Do not use 'showbreak' at the NUL after the text.
-  int added = 0;
+  int head = mb_added;
   char *const sbr = c == NUL ? empty_option : get_showbreak_value(wp);
-  if ((*sbr != NUL || wp->w_p_bri) && wp->w_p_wrap && vcol != 0) {
-    colnr_T sbrlen = 0;
-    int numberwidth = win_col_off(wp);
-
-    numberextra = numberwidth;
-    vcol += numberextra + mb_added;
-
-    if (vcol >= (colnr_T)wp->w_width_inner) {
-      vcol -= wp->w_width_inner;
-      numberextra = wp->w_width_inner - (numberextra - win_col_off2(wp));
-      if (vcol >= numberextra && numberextra > 0) {
-        vcol %= numberextra;
+  if ((*sbr != NUL || wp->w_p_bri) && wp->w_p_wrap) {
+    int col_off_prev = win_col_off(wp);
+    int width2 = wp->w_width_inner - col_off_prev + win_col_off2(wp);
+    colnr_T wcol = vcol + col_off_prev;
+    // cells taken by 'showbreak'/'breakindent' before current char
+    int head_prev = 0;
+    if (wcol >= wp->w_width_inner) {
+      wcol -= wp->w_width_inner;
+      col_off_prev = wp->w_width_inner - width2;
+      if (wcol >= width2 && width2 > 0) {
+        wcol %= width2;
       }
       if (*sbr != NUL) {
-        sbrlen = (colnr_T)mb_charlen(sbr);
-        if (vcol >= sbrlen) {
-          vcol -= sbrlen;
-        }
+        head_prev += vim_strsize(sbr);
       }
-      if (vcol >= numberextra && numberextra > 0) {
-        vcol %= numberextra;
-      } else if (vcol > 0 && numberextra > 0) {
-        vcol += numberwidth - win_col_off2(wp);
+      if (wp->w_p_bri) {
+        head_prev += get_breakindent_win(wp, line);
       }
-
-      numberwidth -= win_col_off2(wp);
+      if (wcol < head_prev) {
+        wcol = head_prev;
+      }
+      wcol += col_off_prev;
     }
 
-    if (vcol == 0 || (vcol + size + sbrlen > (colnr_T)wp->w_width_inner)) {
+    if ((vcol > 0 && wcol == col_off_prev + head_prev)
+        || wcol + size > wp->w_width_inner) {
+      int added = 0;
+      colnr_T max_head_vcol = cts->cts_max_head_vcol;
+
+      if (vcol > 0 && wcol == col_off_prev + head_prev) {
+        added += head_prev;
+        if (max_head_vcol <= 0 || vcol < max_head_vcol) {
+          head += head_prev;
+        }
+      }
+
+      // cells taken by 'showbreak'/'breakindent' halfway current char
+      int head_mid = 0;
       if (*sbr != NUL) {
-        if (size + sbrlen + numberwidth > (colnr_T)wp->w_width_inner) {
+        head_mid += vim_strsize(sbr);
+      }
+      if (wp->w_p_bri) {
+        head_mid += get_breakindent_win(wp, line);
+      }
+      if (head_mid > 0) {
+        if (wcol + size > wp->w_width_inner) {
           // Calculate effective window width.
-          int width = (colnr_T)wp->w_width_inner - sbrlen - numberwidth;
-          int prev_width = vcol ? ((colnr_T)wp->w_width_inner - (sbrlen + vcol))
-                               : 0;
+          int prev_rem = wp->w_width_inner - wcol;
+          int width = width2 - head_mid;
 
           if (width <= 0) {
             width = 1;
           }
-          added += ((size - prev_width) / width) * vim_strsize(sbr);
-          if ((size - prev_width) % width) {
-            // Wrapped, add another length of 'sbr'.
-            added += vim_strsize(sbr);
+          // divide "size - prev_width" by "width", rounding up
+          int cnt = (size - prev_rem + width - 1) / width;
+          added += cnt * head_mid;
+
+          if (max_head_vcol == 0 || vcol + size + added < max_head_vcol) {
+            head += cnt * head_mid;
+          } else if (max_head_vcol > vcol + head_prev + prev_rem) {
+            head += (max_head_vcol - (vcol + head_prev + prev_rem)
+                     + width2 - 1) / width2 * head_mid;
+          } else if (max_head_vcol < 0) {
+            int off = 0;
+            if (c != NUL || !(State & MODE_NORMAL)) {
+              off += cts->cts_cur_text_width_left;
+            }
+            if (c != NUL && (State & MODE_NORMAL)) {
+              off += cts->cts_cur_text_width_right;
+            }
+            if (off >= prev_rem) {
+              head += (1 + (off - prev_rem) / width) * head_mid;
+            }
           }
-        } else {
-          added += vim_strsize(sbr);
         }
       }
 
-      if (wp->w_p_bri) {
-        added += get_breakindent_win(wp, line);
-      }
-
       size += added;
-      if (vcol != 0) {
-        added = 0;
-      }
     }
   }
 
   if (headp != NULL) {
-    *headp = added + mb_added;
+    *headp = head;
   }
   return size;
 }
diff --git a/src/nvim/plines.h b/src/nvim/plines.h
index d89dc7b6f6..153d84e8bb 100644
--- a/src/nvim/plines.h
+++ b/src/nvim/plines.h
@@ -19,6 +19,7 @@ typedef struct {
   MarkTreeIter cts_iter[1];
 
   int cts_vcol;                  ///< virtual column at current position
+  int cts_max_head_vcol;         ///< see win_lbr_chartabsize()
 } chartabsize_T;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
diff --git a/test/functional/ui/decorations_spec.lua b/test/functional/ui/decorations_spec.lua
index ed562555e3..9bbd28c3cb 100644
--- a/test/functional/ui/decorations_spec.lua
+++ b/test/functional/ui/decorations_spec.lua
@@ -2021,7 +2021,7 @@ bbbbbbb]])
     ]]}
   end)
 
-  it('cursor position is correct with virtual text attached to hard tabs', function()
+  it('cursor position is correct with virtual text attached to hard TABs', function()
     command('set noexpandtab')
     feed('i')
     feed('<TAB>')
@@ -2692,7 +2692,7 @@ bbbbbbb]])
       ]]}
   end)
 
-  it('correctly draws when overflowing virtual text is followed by tab with no wrap', function()
+  it('correctly draws when overflowing virtual text is followed by TAB with no wrap', function()
     command('set nowrap')
     feed('i<TAB>test<ESC>')
     meths.buf_set_extmark(
@@ -2984,6 +2984,328 @@ bbbbbbb]])
       {8:-- VISUAL BLOCK --}                                          |
     ]]}
   end)
+
+  local function test_virt_inline_showbreak_smoothscroll()
+    screen:try_resize(30, 6)
+    exec([[
+      highlight! link LineNr Normal
+      call setline(1, repeat('a', 28))
+      setlocal number showbreak=+ breakindent breakindentopt=shift:2
+      setlocal scrolloff=0 smoothscroll
+      normal! $
+    ]])
+    meths.buf_set_extmark(0, ns, 0, 27, { virt_text = { { ('123'):rep(23) } }, virt_text_pos = 'inline' })
+    feed(':<CR>')  -- Have a screen line that doesn't start with spaces
+    screen:expect{grid=[[
+        1 aaaaaaaaaaaaaaaaaaaaaaaaaa|
+            {1:+}a1231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}12312312312312312312312|
+            {1:+}3^a                     |
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}a1231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}12312312312312312312312|
+            {1:+}3^a                     |
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}23123123123123123123123|
+            {1:+}12312312312312312312312|
+            {1:+}3^a                     |
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}12312312312312312312312|
+            {1:+}3^a                     |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}3^a                     |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('zbi')
+    screen:expect{grid=[[
+        1 aaaaaaaaaaaaaaaaaaaaaaaaaa|
+            {1:+}a^1231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}12312312312312312312312|
+            {1:+}3a                     |
+      {8:-- INSERT --}                  |
+    ]]}
+    feed('<BS>')
+    screen:expect{grid=[[
+        1 aaaaaaaaaaaaaaaaaaaaaaaaaa|
+            {1:+}^12312312312312312312312|
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}a                      |
+      {8:-- INSERT --}                  |
+    ]]}
+    feed('<Esc>l')
+    feed(':<CR>')  -- Have a screen line that doesn't start with spaces
+    screen:expect{grid=[[
+        1 aaaaaaaaaaaaaaaaaaaaaaaaaa|
+            {1:+}12312312312312312312312|
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}^a                      |
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}12312312312312312312312|
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}^a                      |
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}^a                      |
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}23123123123123123123123|
+            {1:+}^a                      |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}^a                      |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('023x$')
+    screen:expect{grid=[[
+        1 aaa12312312312312312312312|
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}^a                      |
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}^a                      |
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}23123123123123123123123|
+            {1:+}^a                      |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}^a                      |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      :                             |
+    ]]}
+    feed('zbi')
+    screen:expect{grid=[[
+        1 aaa^12312312312312312312312|
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123123|
+            {1:+}a                      |
+      {1:~                             }|
+      {8:-- INSERT --}                  |
+    ]]}
+    feed('<C-U>')
+    screen:expect{grid=[[
+        1 ^12312312312312312312312312|
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123a  |
+      {1:~                             }|
+      {1:~                             }|
+      {8:-- INSERT --}                  |
+    ]]}
+    feed('<Esc>')
+    screen:expect{grid=[[
+        1 12312312312312312312312312|
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123^a  |
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}31231231231231231231231|
+            {1:+}23123123123123123123^a  |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+            {1:+}23123123123123123123^a  |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+  end
+
+  describe('with showbreak, smoothscroll', function()
+    it('and cpoptions-=n', function()
+      test_virt_inline_showbreak_smoothscroll()
+    end)
+
+    it('and cpoptions+=n', function()
+      command('set cpoptions+=n')
+      -- because of 'breakindent' the screen states are the same
+      test_virt_inline_showbreak_smoothscroll()
+    end)
+  end)
+
+  it('before TABs with smoothscroll', function()
+    screen:try_resize(30, 6)
+    exec([[
+      call setline(1, repeat("\t", 4) .. 'a')
+      setlocal list listchars=tab:<-> scrolloff=0 smoothscroll
+      normal! $
+    ]])
+    meths.buf_set_extmark(0, ns, 0, 3, { virt_text = { { ('12'):rep(32) } }, virt_text_pos = 'inline' })
+    screen:expect{grid=[[
+      {1:<------><------><------>}121212|
+      121212121212121212121212121212|
+      1212121212121212121212121212{1:<-}|
+      {1:----->}^a                       |
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+      {1:<<<}212121212121212121212121212|
+      1212121212121212121212121212{1:<-}|
+      {1:----->}^a                       |
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+      {1:<<<}2121212121212121212121212{1:<-}|
+      {1:----->}^a                       |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+      {1:<<<-->}^a                       |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('zbh')
+    screen:expect{grid=[[
+      {1:<------><------><------>}121212|
+      121212121212121212121212121212|
+      1212121212121212121212121212{1:^<-}|
+      {1:----->}a                       |
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('i')
+    screen:expect{grid=[[
+      {1:<------><------><------>}^121212|
+      121212121212121212121212121212|
+      1212121212121212121212121212{1:<-}|
+      {1:----->}a                       |
+      {1:~                             }|
+      {8:-- INSERT --}                  |
+    ]]}
+    feed('<C-O>:setlocal nolist<CR>')
+    screen:expect{grid=[[
+                              ^121212|
+      121212121212121212121212121212|
+      1212121212121212121212121212  |
+            a                       |
+      {1:~                             }|
+      {8:-- INSERT --}                  |
+    ]]}
+    feed('<Esc>l')
+    screen:expect{grid=[[
+                              121212|
+      121212121212121212121212121212|
+      1212121212121212121212121212  |
+           ^ a                       |
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+      {1:<<<}212121212121212121212121212|
+      1212121212121212121212121212  |
+           ^ a                       |
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+      {1:<<<}2121212121212121212121212  |
+           ^ a                       |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+      {1:<<<}  ^ a                       |
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+      {1:~                             }|
+                                    |
+    ]]}
+  end)
 end)
 
 describe('decorations: virtual lines', function()
@@ -3643,7 +3965,7 @@ if (h->n_buckets < new_n_buckets) { // expand
   end)
 
 
-  it('works with hard tabs', function()
+  it('works with hard TABs', function()
     insert(example_text2)
     feed 'gg'
     meths.buf_set_extmark(0, ns, 1, 0, {
diff --git a/test/old/testdir/test_listlbr.vim b/test/old/testdir/test_listlbr.vim
index 2e66fd4ccb..9b9bf63864 100644
--- a/test/old/testdir/test_listlbr.vim
+++ b/test/old/testdir/test_listlbr.vim
@@ -14,7 +14,7 @@ function s:screen_lines(lnum, width) abort
 endfunction
 
 func s:compare_lines(expect, actual)
-  call assert_equal(join(a:expect, "\n"), join(a:actual, "\n"))
+  call assert_equal(a:expect, a:actual)
 endfunc
 
 function s:test_windows(...)
@@ -330,4 +330,47 @@ func Test_list_with_tab_and_skipping_first_chars()
 \ ]
   call s:compare_lines(expect, lines)
   call s:close_windows()
-endfu
+endfunc
+
+func Test_ctrl_char_on_wrap_column()
+  call s:test_windows("setl nolbr wrap sbr=")
+  call setline(1, 'aaa' .. repeat("\<C-A>", 150) .. 'bbb')
+  call cursor(1,1)
+  norm! $
+  redraw!
+  let expect=[
+\ '<<<^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^A^A^A^A^A^A^A^A^A^',
+\ 'A^Abbb              ']
+  let lines = s:screen_lines([1, 10], winwidth(0))
+  call s:compare_lines(expect, lines)
+  call assert_equal(len(expect), winline())
+  call assert_equal(strwidth(trim(expect[-1], ' ', 2)), wincol())
+  setl sbr=!!
+  redraw!
+  let expect=[
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^A^A^A^',
+\ '!!A^A^A^A^A^A^Abbb  ']
+  let lines = s:screen_lines([1, 10], winwidth(0))
+  call s:compare_lines(expect, lines)
+  call assert_equal(len(expect), winline())
+  call assert_equal(strwidth(trim(expect[-1], ' ', 2)), wincol())
+  call s:close_windows()
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab
diff --git a/test/old/testdir/test_listlbr_utf8.vim b/test/old/testdir/test_listlbr_utf8.vim
index 15b248964f..1bbbd2d2ae 100644
--- a/test/old/testdir/test_listlbr_utf8.vim
+++ b/test/old/testdir/test_listlbr_utf8.vim
@@ -249,7 +249,6 @@ endfunc
 
 func Test_chinese_char_on_wrap_column()
   call s:test_windows("setl nolbr wrap sbr=")
-  syntax off
   call setline(1, [
 \ 'aaaaaaaaaaaaaaaaaaa中'.
 \ 'aaaaaaaaaaaaaaaaa中'.
@@ -278,5 +277,85 @@ func Test_chinese_char_on_wrap_column()
 \ '中hello             ']
   let lines = s:screen_lines([1, 10], winwidth(0))
   call s:compare_lines(expect, lines)
+  call assert_equal(len(expect), winline())
+  call assert_equal(strwidth(trim(expect[-1], ' ', 2)), wincol())
   call s:close_windows()
-endfu
+endfunc
+
+func Test_chinese_char_on_wrap_column_sbr()
+  call s:test_windows("setl nolbr wrap sbr=!!!")
+  call setline(1, [
+\ 'aaaaaaaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'aaaaaaaaaaaaaa中'.
+\ 'hello'])
+  call cursor(1,1)
+  norm! $
+  redraw!
+  let expect=[
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中aaaaaaaaaaaaaa>',
+\ '!!!中hello          ']
+  let lines = s:screen_lines([1, 10], winwidth(0))
+  call s:compare_lines(expect, lines)
+  call assert_equal(len(expect), winline())
+  call assert_equal(strwidth(trim(expect[-1], ' ', 2)), wincol())
+  call s:close_windows()
+endfunc
+
+func Test_unprintable_char_on_wrap_column()
+  call s:test_windows("setl nolbr wrap sbr=")
+  call setline(1, 'aaa' .. repeat("\uFEFF", 50) .. 'bbb')
+  call cursor(1,1)
+  norm! $
+  redraw!
+  let expect=[
+\ '<<<<feff><feff><feff',
+\ '><feff><feff><feff><',
+\ 'feff><feff><feff><fe',
+\ 'ff><feff><feff><feff',
+\ '><feff><feff><feff><',
+\ 'feff><feff><feff><fe',
+\ 'ff><feff><feff><feff',
+\ '><feff><feff><feff><',
+\ 'feff><feff><feff><fe',
+\ 'ff>bbb              ']
+  let lines = s:screen_lines([1, 10], winwidth(0))
+  call s:compare_lines(expect, lines)
+  call assert_equal(len(expect), winline())
+  call assert_equal(strwidth(trim(expect[-1], ' ', 2)), wincol())
+  setl sbr=!!
+  redraw!
+  let expect=[
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff><feff',
+\ '!!><feff><feff>bbb  ']
+  let lines = s:screen_lines([1, 10], winwidth(0))
+  call s:compare_lines(expect, lines)
+  call assert_equal(len(expect), winline())
+  call assert_equal(strwidth(trim(expect[-1], ' ', 2)), wincol())
+  call s:close_windows()
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab