fix: local winbar with tabs

Closes #19396

src/nvim/option.c

@@ -3021,7 +3021,7 @@ ambw_end:
     }
     // add / remove window bars for 'winbar'
     if (gvarp == (char_u **)&p_wbr) {
-      set_winbar();
+      set_winbar(true);
     }
   } else if (gvarp == &p_cpt) {
     // check if it is a valid value for 'complete' -- Acevedo
@@ -6455,6 +6455,7 @@ 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);
   wp->w_grid_alloc.blending = wp->w_p_winbl > 0;
 }
 

src/nvim/window.c

@@ -4111,7 +4111,6 @@ int win_new_tabpage(int after, char_u *filename)
 
     newtp->tp_topframe = topframe;
     last_status(false);
-    set_winbar();
 
     redraw_all_later(NOT_VALID);
 
@@ -6740,10 +6739,13 @@ static void last_status_rec(frame_T *fr, bool statusline, bool is_stl_global)
   }
 }
 
-// Add or remove window bars from windows depending on the value of 'winbar'.
+/// Add or remove window bar from window "wp".
-void set_winbar(void)
+///
+/// @param make_room Whether to resize frames to make room for winbar.
+///
+/// @return Success status.
+int set_winbar_win(win_T *wp, bool make_room)
 {
-  FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
   // 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)
                                      : ((*p_wbr != NUL || *wp->w_p_wbr != NUL) ? 1 : 0);
@@ -6752,9 +6754,9 @@ void set_winbar(void)
     if (winbar_height == 1 && wp->w_height_inner <= 1) {
       if (wp->w_floating) {
         emsg(_(e_noroom));
-          continue;
+        return NOTDONE;
-        } else if (!resize_frame_for_winbar(wp->w_frame)) {
+      } else if (!make_room || !resize_frame_for_winbar(wp->w_frame)) {
-          return;
+        return FAIL;
       }
     }
     wp->w_winbar_height = winbar_height;
@@ -6769,6 +6771,19 @@ void set_winbar(void)
       wp->w_winbar_click_defs = NULL;
     }
   }
+
+  return OK;
+}
+
+/// Add or remove window bars from all windows in tab depending on the value of 'winbar'.
+///
+/// @param make_room Whether to resize frames to make room for winbar.
+void set_winbar(bool make_room)
+{
+  FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
+    if (set_winbar_win(wp, make_room) == FAIL) {
+      break;
+    }
   }
 }
 

test/functional/ui/winbar_spec.lua

@@ -578,3 +578,48 @@ describe('winbar', function()
     eq('Vim(set):E36: Not enough room', pcall_err(command, 'set winbar=test'))
   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:~                                                           }|
+                                                                |
+  ]]}
+end)