fix: Delay creation of chat and diff buffers until they are needed

lua/CopilotChat/chat.lua

@@ -34,11 +34,10 @@ local function create_buf()
   return bufnr
 end
 
-local Chat = class(function(self, name, on_buf_create)
+local Chat = class(function(self, on_buf_create)
   self.on_buf_create = on_buf_create
-  self.bufnr = create_buf()
-  self.on_buf_create(self.bufnr)
-  self.spinner = Spinner(self.bufnr, name)
+  self.bufnr = nil
+  self.spinner = nil
   self.winnr = nil
 end)
 
@@ -55,9 +54,14 @@ function Chat:validate()
     return
   end
   self.bufnr = create_buf()
-  self.on_buf_create(self.bufnr)
-  self.spinner.bufnr = self.bufnr
+  if not self.spinner then
+    self.spinner = Spinner(self.bufnr, 'copilot-chat')
+  else
+    self.spinner.bufnr = self.bufnr
+  end
+
   self:close()
+  self.on_buf_create(self.bufnr)
 end
 
 function Chat:last()

lua/CopilotChat/diff.lua

@@ -40,9 +40,7 @@ local Diff = class(function(self, on_buf_create, help)
   self.current = nil
   self.ns = vim.api.nvim_create_namespace('copilot-diff')
   self.mark_ns = vim.api.nvim_create_namespace('copilot-diff-mark')
-  self.bufnr = create_buf()
-  self.on_buf_create(self.bufnr)
-
+  self.bufnr = nil
   vim.api.nvim_set_hl(self.ns, '@diff.plus', { bg = blend_color_with_neovim_bg('DiffAdd', 20) })
   vim.api.nvim_set_hl(self.ns, '@diff.minus', { bg = blend_color_with_neovim_bg('DiffDelete', 20) })
   vim.api.nvim_set_hl(self.ns, '@diff.delta', { bg = blend_color_with_neovim_bg('DiffChange', 20) })

lua/CopilotChat/init.lua

@@ -434,7 +434,7 @@ function M.setup(config)
       .. "' to accept diff."
   )
 
-  state.chat = Chat(plugin_name, function(bufnr)
+  state.chat = Chat(function(bufnr)
     if M.config.mappings.complete then
       vim.keymap.set('i', M.config.mappings.complete, complete, { buffer = bufnr })
     end
@@ -495,12 +495,13 @@ function M.setup(config)
         end
       end, { buffer = bufnr })
     end
+
+    M.reset()
   end)
 
   tiktoken.setup()
   debuginfo.setup()
   M.debug(M.config.debug)
-  M.reset()
 
   for name, prompt in pairs(M.prompts(true)) do
     vim.api.nvim_create_user_command('CopilotChat' .. name, function(args)