feat: support for binary file accessible by PATH

Fixes #457

Author: AntoineGS

README.md

@@ -413,7 +413,8 @@ require("copilot").setup {
 
 `type` can be either `"nodejs"` or `"binary"`. The binary version will be downloaded if used.
 
-`custom_server_filepath` is used to specify the path of either the path (filename included) of the `js` file if using `"nodejs"` or the path to the binary if using `"binary"`.
+`custom_server_filepath` is used to specify the server path (filename included) of either the `js` file if using `"nodejs"` or to the binary if using `"binary"`.
+The filename on its own can also be set if accessible through your PATH.
 When using `"binary"`, the download process will be disabled and the binary will be used directly.
 example:
 

lua/copilot/config/server.lua

@@ -1,6 +1,6 @@
 ---@class (exact) ServerConfig
 ---@field type string<'nodejs', 'binary'> Type of the server
----@field custom_server_filepath? string|nil Path to the custom server file
+---@field custom_server_filepath? string|nil Path to the custom server file, can be absolute, relative or a file name (for PATH)
 
 local server = {
   ---@type ServerConfig
@@ -10,6 +10,7 @@ local server = {
   },
 }
 
+-- TODO: add support for relative paths
 ---@param config ServerConfig
 function server.validate(config)
   vim.validate("type", config.type, function(server_type)

lua/copilot/lsp/binary.lua

@@ -348,7 +348,7 @@ end
 ---@param custom_server_path? string
 function M.setup(custom_server_path)
   if custom_server_path then
-    if vim.fn.filereadable(custom_server_path) == 0 then
+    if vim.fn.filereadable(custom_server_path) == 0 and vim.fn.executable(custom_server_path) == 0 then
       logger.error("copilot-language-server not found at " .. custom_server_path)
       return M
     end