fix(winbar): do not always assume cursor is valid. fixes #19458

6 files changed, 119 insertions, 67 deletions

diff --git a/src/nvim/api/win_config.c b/src/nvim/api/win_config.c
index 969643eeef..a153f746b6 100644
--- a/src/nvim/api/win_config.c
+++ b/src/nvim/api/win_config.c
@@ -167,7 +167,7 @@ Window nvim_open_win(Buffer buffer, Boolean enter, Dict(float_config) *config, E
 
   if (fconfig.style == kWinStyleMinimal) {
     win_set_minimal_style(wp);
-    didset_window_options(wp);
+    didset_window_options(wp, true);
   }
   return wp->handle;
 }
@@ -209,7 +209,7 @@ void nvim_win_set_config(Window window, Dict(float_config) *config, Error *err)
   }
   if (fconfig.style == kWinStyleMinimal) {
     win_set_minimal_style(win);
-    didset_window_options(win);
+    didset_window_options(win, true);
   }
 }
 
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 7c187ca735..ce788cc7a0 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -2596,7 +2596,7 @@ void get_winopts(buf_T *buf)
   }
 
   if (curwin->w_float_config.style == kWinStyleMinimal) {
-    didset_window_options(curwin);
+    didset_window_options(curwin, false);
     win_set_minimal_style(curwin);
   }
 
@@ -2604,7 +2604,7 @@ void get_winopts(buf_T *buf)
   if (p_fdls >= 0) {
     curwin->w_p_fdl = p_fdls;
   }
-  didset_window_options(curwin);
+  didset_window_options(curwin, false);
 }
 
 /// Find the mark for the buffer 'buf' for the current window.
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 3305f2c16d..916c460ed6 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -1981,7 +1981,7 @@ static void didset_options(void)
   (void)check_cedit();
   // initialize the table for 'breakat'.
   fill_breakat_flags();
-  didset_window_options(curwin);
+  didset_window_options(curwin, true);
 }
 
 // More side effects of setting options.
@@ -6303,7 +6303,7 @@ void win_copy_options(win_T *wp_from, win_T *wp_to)
 {
   copy_winopt(&wp_from->w_onebuf_opt, &wp_to->w_onebuf_opt);
   copy_winopt(&wp_from->w_allbuf_opt, &wp_to->w_allbuf_opt);
-  didset_window_options(wp_to);
+  didset_window_options(wp_to, true);
 }
 
 /// Copy the options from one winopt_T to another.
@@ -6428,7 +6428,7 @@ void clear_winopt(winopt_T *wop)
   clear_string_option((char_u **)&wop->wo_wbr);
 }
 
-void didset_window_options(win_T *wp)
+void didset_window_options(win_T *wp, bool valid_cursor)
 {
   check_colorcolumn(wp);
   briopt_check(wp);
@@ -6437,7 +6437,7 @@ void didset_window_options(win_T *wp)
   set_chars_option(wp, &wp->w_p_lcs, true);
   parse_winhl_opt(wp);  // sets w_hl_needs_update also for w_p_winbl
   check_blending(wp);
-  set_winbar_win(wp, false);
+  set_winbar_win(wp, false, valid_cursor);
   wp->w_grid_alloc.blending = wp->w_p_winbl > 0;
 }
 
diff --git a/src/nvim/ui.c b/src/nvim/ui.c
index 2cbdeb318b..be0dda0a2f 100644
--- a/src/nvim/ui.c
+++ b/src/nvim/ui.c
@@ -662,6 +662,6 @@ void ui_grid_resize(handle_T grid_handle, int width, int height, Error *error)
     // non-positive indicates no request
     wp->w_height_request = MAX(height, 0);
     wp->w_width_request = MAX(width, 0);
-    win_set_inner_size(wp);
+    win_set_inner_size(wp, true);
   }
 }
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 1eff379f77..9d2432ea3b 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -705,7 +705,7 @@ win_T *win_new_float(win_T *wp, bool last, FloatConfig fconfig, Error *err)
   wp->w_vsep_width = 0;
 
   win_config_float(wp, fconfig);
-  win_set_inner_size(wp);
+  win_set_inner_size(wp, true);
   wp->w_pos_changed = true;
   redraw_later(wp, VALID);
   return wp;
@@ -789,7 +789,7 @@ void win_config_float(win_T *wp, FloatConfig fconfig)
     wp->w_width = MIN(wp->w_width, Columns - win_border_width(wp));
   }
 
-  win_set_inner_size(wp);
+  win_set_inner_size(wp, true);
   must_redraw = MAX(must_redraw, VALID);
 
   wp->w_pos_changed = true;
@@ -6162,7 +6162,7 @@ void win_new_height(win_T *wp, int height)
 
   wp->w_height = height;
   wp->w_pos_changed = true;
-  win_set_inner_size(wp);
+  win_set_inner_size(wp, true);
 }
 
 void scroll_to_fraction(win_T *wp, int prev_height)
@@ -6271,7 +6271,7 @@ void scroll_to_fraction(win_T *wp, int prev_height)
   invalidate_botline_win(wp);
 }
 
-void win_set_inner_size(win_T *wp)
+void win_set_inner_size(win_T *wp, bool valid_cursor)
 {
   int width = wp->w_width_request;
   if (width == 0) {
@@ -6285,7 +6285,7 @@ void win_set_inner_size(win_T *wp)
   }
 
   if (height != prev_height) {
-    if (height > 0) {
+    if (height > 0 && valid_cursor) {
       if (wp == curwin) {
         // w_wrow needs to be valid. When setting 'laststatus' this may
         // call win_new_height() recursively.
@@ -6304,7 +6304,7 @@ void win_set_inner_size(win_T *wp)
     // There is no point in adjusting the scroll position when exiting.  Some
     // values might be invalid.
     // Skip scroll_to_fraction() when 'cmdheight' was set to one from zero.
-    if (!exiting && !made_cmdheight_nonzero) {
+    if (!exiting && !made_cmdheight_nonzero && valid_cursor) {
       scroll_to_fraction(wp, prev_height);
     }
     redraw_later(wp, NOT_VALID);  // SOME_VALID??
@@ -6313,11 +6313,13 @@ void win_set_inner_size(win_T *wp)
   if (width != wp->w_width_inner) {
     wp->w_width_inner = width;
     wp->w_lines_valid = 0;
-    changed_line_abv_curs_win(wp);
-    invalidate_botline_win(wp);
-    if (wp == curwin) {
-      update_topline(wp);
-      curs_columns(wp, true);  // validate w_wrow
+    if (valid_cursor) {
+      changed_line_abv_curs_win(wp);
+      invalidate_botline_win(wp);
+      if (wp == curwin) {
+        update_topline(wp);
+        curs_columns(wp, true);  // validate w_wrow
+      }
     }
     redraw_later(wp, NOT_VALID);
   }
@@ -6346,7 +6348,7 @@ static int win_border_width(win_T *wp)
 void win_new_width(win_T *wp, int width)
 {
   wp->w_width = width;
-  win_set_inner_size(wp);
+  win_set_inner_size(wp, true);
 
   wp->w_redr_status = true;
   wp->w_pos_changed = true;
@@ -6738,9 +6740,11 @@ static void last_status_rec(frame_T *fr, bool statusline, bool is_stl_global)
 /// Add or remove window bar from window "wp".
 ///
 /// @param make_room Whether to resize frames to make room for winbar.
+/// @param valid_cursor Whether the cursor is valid and should be used while
+///                     resizing.
 ///
 /// @return Success status.
-int set_winbar_win(win_T *wp, bool make_room)
+int set_winbar_win(win_T *wp, bool make_room, bool valid_cursor)
 {
   // Require the local value to be set in order to show winbar on a floating window.
   int winbar_height = wp->w_floating ? ((*wp->w_p_wbr != NUL) ? 1 : 0)
@@ -6756,7 +6760,7 @@ int set_winbar_win(win_T *wp, bool make_room)
       }
     }
     wp->w_winbar_height = winbar_height;
-    win_set_inner_size(wp);
+    win_set_inner_size(wp, valid_cursor);
     wp->w_redr_status = wp->w_redr_status || winbar_height;
 
     if (winbar_height == 0) {
@@ -6777,7 +6781,7 @@ int set_winbar_win(win_T *wp, bool make_room)
 void set_winbar(bool make_room)
 {
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
-    if (set_winbar_win(wp, make_room) == FAIL) {
+    if (set_winbar_win(wp, make_room, true) == FAIL) {
       break;
     }
   }
diff --git a/test/functional/ui/winbar_spec.lua b/test/functional/ui/winbar_spec.lua
index 60fa10da87..8976c4371f 100644
--- a/test/functional/ui/winbar_spec.lua
+++ b/test/functional/ui/winbar_spec.lua
@@ -579,47 +579,95 @@ describe('winbar', function()
   end)
 end)
 
-it('local winbar works with tabs', function()
-  clear()
-  local screen = Screen.new(60, 13)
-  screen:attach()
-  screen:set_default_attr_ids({
-    [1] = {bold = true},
-    [2] = {reverse = true},
-    [3] = {bold = true, foreground = Screen.colors.Blue},
-    [4] = {underline = true, background = Screen.colors.LightGray}
-  })
-  meths.set_option_value('winbar', 'foo', { scope = 'local', win = 0 })
-  command('tabnew')
-  screen:expect([[
-    {4: [No Name] }{1: [No Name] }{2:                                     }{4:X}|
-    ^                                                            |
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-                                                                |
-  ]])
-  command('tabnext')
-  screen:expect{grid=[[
-    {1: [No Name] }{4: [No Name] }{2:                                     }{4:X}|
-    {1:foo                                                         }|
-    ^                                                            |
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-    {3:~                                                           }|
-                                                                |
-  ]]}
+describe('local winbar with tabs', function()
+  local screen
+  before_each(function()
+    clear()
+    screen = Screen.new(60, 10)
+    screen:attach()
+    screen:set_default_attr_ids({
+      [1] = {bold = true},
+      [2] = {reverse = true},
+      [3] = {bold = true, foreground = Screen.colors.Blue},
+      [4] = {underline = true, background = Screen.colors.LightGray}
+    })
+    meths.set_option_value('winbar', 'foo', { scope = 'local', win = 0 })
+  end)
+
+  it('works', function()
+    command('tabnew')
+    screen:expect([[
+      {4: [No Name] }{1: [No Name] }{2:                                     }{4:X}|
+      ^                                                            |
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+                                                                  |
+    ]])
+    command('tabnext')
+    screen:expect{grid=[[
+      {1: [No Name] }{4: [No Name] }{2:                                     }{4:X}|
+      {1:foo                                                         }|
+      ^                                                            |
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+                                                                  |
+    ]]}
+  end)
+
+  it('can edit new empty buffer #19458', function()
+    insert [[
+      some
+      goofy
+      text]]
+    screen:expect{grid=[[
+      {1:foo                                                         }|
+      some                                                        |
+      goofy                                                       |
+      tex^t                                                        |
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+                                                                  |
+    ]]}
+
+    -- this used to throw an E315 ml_get error
+    command 'tabedit'
+    screen:expect{grid=[[
+      {4: + [No Name] }{1: [No Name] }{2:                                   }{4:X}|
+      ^                                                            |
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+                                                                  |
+    ]]}
+
+    command 'tabprev'
+    screen:expect{grid=[[
+      {1: + [No Name] }{4: [No Name] }{2:                                   }{4:X}|
+      {1:foo                                                         }|
+      some                                                        |
+      goofy                                                       |
+      tex^t                                                        |
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+      {3:~                                                           }|
+                                                                  |
+    ]]}
+  end)
 end)