feat: add a default should_attach function that includes the buffer logic

This allows attaching to non-buflisted buffers through custom logic.
Fixes zbirenbaum#279
Fixes zbirenbaum#239

Author: AntoineGS

README.md

@@ -116,7 +116,19 @@ require('copilot').setup({
   root_dir = function()
     return vim.fs.dirname(vim.fs.find(".git", { upward = true })[1])
   end,
-  should_attach = nil, -- type is fun(bufnr: integer, bufname: string): boolean
+  should_attach = function(_, _)
+    if not vim.bo.buflisted then
+      logger.debug("not attaching, buffer is not 'buflisted'")
+      return false
+    end
+
+    if vim.bo.buftype ~= "" then
+      logger.debug("not attaching, buffer 'buftype' is " .. vim.bo.buftype)
+      return false
+    end
+
+    return true
+  end,
   server_opts_overrides = {},
 })
 ```
@@ -324,6 +336,7 @@ If none is found, it will use the current working directory.
 
 This function is called to determine if copilot should attach to the buffer or not.
 It is useful if you would like to go beyond the filetypes and have more control over when copilot should attach.
+You can also use it to attach to buflisted buffers by simply omiting that portion from the function.
 Since this happens before attaching to the buffer, it is good to prevent Copilot from reading sensitive files.
 
 An example of this would be:

lua/copilot/client.lua

@@ -17,7 +17,7 @@ local M = {
   node_version_error = nil,
   startup_error = nil,
   initialized = false,
-  ---@type copilot_should_attach|nil
+  ---@type copilot_should_attach
   should_attach = nil,
 }
 
@@ -95,22 +95,15 @@ end
 
 ---@param force? boolean
 function M.buf_attach(force)
-  if M.should_attach then
-    local bufnr = vim.api.nvim_get_current_buf()
-    local bufname = vim.api.nvim_buf_get_name(bufnr)
-
-    if not M.should_attach(bufnr, bufname) then
-      logger.debug("copilot is disabled by should_attach")
-      return
-    end
-  end
-
   if is_disabled then
     logger.warn("copilot is disabled")
     return
   end
 
-  if not force and not util.should_attach() then
+  local bufnr = vim.api.nvim_get_current_buf()
+  local bufname = vim.api.nvim_buf_get_name(bufnr)
+
+  if not force and not M.should_attach(bufnr, bufname) and not util.should_attach() then
     return
   end
 

lua/copilot/config.lua

@@ -62,8 +62,20 @@ local default_config = {
     return vim.fs.dirname(vim.fs.find(".git", { upward = true })[1])
   end,
   ---@alias copilot_should_attach fun(bufnr: integer, bufname: string): boolean
-  ---@type copilot_should_attach|nil
-  should_attach = nil,
+  ---@type copilot_should_attach
+  should_attach = function(_, _)
+    if not vim.bo.buflisted then
+      logger.debug("not attaching, bugger is not 'buflisted'")
+      return false
+    end
+
+    if vim.bo.buftype ~= "" then
+      logger.debug("not attaching, buffer 'buftype' is " .. vim.bo.buftype)
+      return false
+    end
+
+    return true
+  end,
 }
 
 local mod = {

lua/copilot/util.lua

@@ -104,14 +104,6 @@ function M.should_attach()
     return not ft_disabled, ft_disabled_reason
   end
 
-  if not vim.bo.buflisted then
-    return false, "buffer not 'buflisted'"
-  end
-
-  if vim.bo.buftype ~= "" then
-    return false, "buffer 'buftype' is " .. vim.bo.buftype
-  end
-
   return true
 end