fix(highlights): winbar highlights changed after hovering/clicking if…

… not defined

lua/dropbar/bar.lua

@@ -662,15 +662,16 @@ function dropbar_t:update_current_context_hl(bar_idx)
   end
   local hl_currentcontext_icon = '_DropBarIconCurrentContext'
   local hl_currentcontext_name = '_DropBarCurrentContext'
+  symbol:restore()
   vim.api.nvim_set_hl(
     0,
     hl_currentcontext_icon,
-    utils.hl.merge(symbol.icon_hl or 'WinBar', 'DropBarCurrentContext')
+    utils.hl.merge('WinBarNC', symbol.icon_hl, 'DropBarCurrentContext')
   )
   vim.api.nvim_set_hl(
     0,
     hl_currentcontext_name,
-    utils.hl.merge(symbol.name_hl or 'WinBar', 'DropBarCurrentContext')
+    utils.hl.merge('WinBarNC', symbol.name_hl, 'DropBarCurrentContext')
   )
   symbol:swap_field('icon_hl', hl_currentcontext_icon)
   symbol:swap_field('name_hl', hl_currentcontext_name)
@@ -681,6 +682,7 @@ end
 ---@param col integer? displaywidth-indexed, 0-indexed mouse position, nil to clear the hover highlights
 ---@return nil
 function dropbar_t:update_hover_hl(col)
+  print('update_hover_hl')
   if not col then
     if self.symbol_on_hover then
       self.symbol_on_hover:restore()
@@ -695,15 +697,17 @@ function dropbar_t:update_hover_hl(col)
   end
   local hl_hover_icon = '_DropBarIconHover'
   local hl_hover_name = '_DropBarHover'
+  local hl_winbar = vim.api.nvim_get_current_win() == self.win and 'WinBar'
+    or 'WinbarNC'
   vim.api.nvim_set_hl(
     0,
     hl_hover_icon,
-    utils.hl.merge(symbol.icon_hl or 'WinBar', 'DropBarHover')
+    utils.hl.merge(hl_winbar, symbol.icon_hl, 'DropBarHover')
   )
   vim.api.nvim_set_hl(
     0,
     hl_hover_name,
-    utils.hl.merge(symbol.name_hl or 'WinBar', 'DropBarHover')
+    utils.hl.merge(hl_winbar, symbol.name_hl, 'DropBarHover')
   )
   symbol:swap_field('icon_hl', hl_hover_icon)
   symbol:swap_field('name_hl', hl_hover_name)

lua/dropbar/menu.lua

@@ -366,7 +366,7 @@ function dropbar_menu_t:add_hl(hl_info)
   end
   for linenr, hl_line_info in ipairs(hl_info) do
     for _, hl_symbol_info in ipairs(hl_line_info) do
-      vim.api.nvim_buf_add_highlight(
+      utils.hl.buf_add_hl(
         self.buf,
         hl_symbol_info.ns or -1,
         hl_symbol_info.hlgroup,

lua/dropbar/utils/hl.lua

@@ -1,5 +1,50 @@
 local M = {}
 
+---Wrapper of nvim_get_hl(), but does not create a cleared highlight group
+---if it doesn't exist
+---NOTE: vim.api.nvim_get_hl() has a side effect, it will create a cleared
+---highlight group if it doesn't exist, see
+---https://github.com/neovim/neovim/issues/24583
+---This affects regions highlighted by non-existing highlight groups in a
+---winbar, which should falls back to the default 'WinBar' or 'WinBarNC'
+---highlight groups but instead falls back to 'Normal' highlight group
+---because of this side effect
+---So we need to check if the highlight group exists before calling
+---vim.api.nvim_get_hl()
+---@param ns_id integer
+---@param opts table{ name: string?, id: integer?, link: boolean? }
+---@return table highlight attributes
+function M.get_hl(ns_id, opts)
+  if not opts.name then
+    return vim.api.nvim_get_hl(ns_id, opts)
+  end
+  return vim.fn.hlexists(opts.name) == 1 and vim.api.nvim_get_hl(ns_id, opts)
+    or {}
+end
+
+---Wrapper of nvim_buf_add_highlight(), but does not create a cleared
+---highlight group if it doesn't exist
+---@param buffer integer buffer handle, or 0 for current buffer
+---@param ns_id integer namespace to use or -1 for ungrouped highlight
+---@param hl_group string name of the highlight group to use
+---@param line integer line to highlight (zero-indexed)
+---@param col_start integer start of (byte-indexed) column range to highlight
+---@param col_end integer end of (byte-indexed) column range to highlight, or -1 to highlight to end of line
+---@return nil
+function M.buf_add_hl(buffer, ns_id, hl_group, line, col_start, col_end)
+  if vim.fn.hlexists(hl_group) == 0 then
+    return
+  end
+  vim.api.nvim_buf_add_highlight(
+    buffer,
+    ns_id,
+    hl_group,
+    line,
+    col_start,
+    col_end
+  )
+end
+
 ---Highlight text in buffer, clear previous highlight if any exists
 ---@param buf integer
 ---@param hlgroup string
@@ -13,14 +58,7 @@ function M.range_single(buf, hlgroup, range)
         or 0
       local end_col = linenr == range['end'].line and range['end'].character
         or -1
-      vim.api.nvim_buf_add_highlight(
-        buf,
-        ns,
-        hlgroup,
-        linenr,
-        start_col,
-        end_col
-      )
+      M.buf_add_hl(buf, ns, hlgroup, linenr, start_col, end_col)
     end
   end
 end
@@ -47,12 +85,19 @@ end
 ---@vararg string highlight group names
 ---@return table merged highlight attributes
 function M.merge(...)
+  -- Eliminate nil values in vararg
+  local hl_names = {}
+  for _, hl_name in pairs({ ... }) do
+    if hl_name then
+      table.insert(hl_names, hl_name)
+    end
+  end
   local hl_attr = vim.tbl_map(function(hl_name)
-    return vim.api.nvim_get_hl(0, {
+    return M.get_hl(0, {
       name = hl_name,
       link = false,
     })
-  end, { ... })
+  end, hl_names)
   return vim.tbl_extend('force', unpack(hl_attr))
 end