fix: RPC Document for URI not found on ft change

fixes zbirenbaum#491

Author: AntoineGS

.gitignore

@@ -1,3 +1,5 @@
 tests/logs
 tests/env.lua
 deps/
+
+tests/files/test.txt

lua/copilot/client/init.lua

@@ -101,6 +101,7 @@ function M.buf_attach(force, bufnr)
   end
 
   vim.lsp.buf_attach_client(bufnr, M.id)
+  util.set_buffer_previous_ft(bufnr, vim.bo[bufnr].filetype)
   if force then
     logger.debug("force attached to buffer")
     util.set_buffer_attach_status(bufnr, ATTACH_STATUS_FORCE_ATTACHED)
@@ -110,11 +111,12 @@ function M.buf_attach(force, bufnr)
   end
 end
 
-function M.buf_detach()
-  if M.buf_is_attached(0) then
-    vim.lsp.buf_detach_client(0, M.id)
-    logger.trace("buffer manuall detached")
-    util.set_buffer_attach_status(vim.api.nvim_get_current_buf(), ATTACH_STATUS_MANUALLY_DETACHED)
+---@param bufnr? integer
+function M.buf_detach_if_attached(bufnr)
+  bufnr = bufnr or vim.api.nvim_get_current_buf()
+  if M.buf_is_attached(bufnr) then
+    vim.lsp.buf_detach_client(bufnr, M.id)
+    util.set_buffer_attach_status(bufnr, ATTACH_STATUS_NOT_ATTACHED_PREFIX .. "detached")
   end
 end
 
@@ -166,6 +168,23 @@ function M.use_client(callback)
   end
 end
 
+---@param bufnr integer
+local function on_filetype(bufnr)
+  logger.trace("filetype autocmd called")
+  vim.schedule(function()
+    -- todo: when we do lazy/late attaching this needs changing
+
+    -- This is to handle the case where the filetype changes after the buffer is already attached,
+    -- causing the LSP to raise an error
+    if util.get_buffer_previous_ft(bufnr) ~= vim.bo[bufnr].filetype then
+      logger.trace("filetype changed, detaching and re-attaching")
+      M.buf_detach_if_attached(bufnr)
+    end
+
+    M.buf_attach(false, bufnr)
+  end)
+end
+
 function M.setup()
   logger.trace("setting up client")
   local node_command = config.copilot_node_command
@@ -193,11 +212,7 @@ function M.setup()
     group = M.augroup,
     callback = function(args)
       local bufnr = (args and args.buf) or nil
-      logger.trace("filetype autocmd called")
-      vim.schedule(function()
-        -- todo: when we do lazy/late attaching this needs changing
-        M.buf_attach(false, bufnr)
-      end)
+      on_filetype(bufnr)
     end,
     desc = "[copilot] (suggestion) file type",
   })

lua/copilot/command.lua

@@ -49,8 +49,11 @@ function M.attach(opts)
 end
 
 function M.detach()
-  if c.buf_is_attached(0) then
-    c.buf_detach()
+  local bufnr = vim.api.nvim_get_current_buf()
+  if c.buf_is_attached(bufnr) then
+    c.buf_detach_if_attached(bufnr)
+    logger.trace("buffer manually detached")
+    u.set_buffer_attach_status(bufnr, ATTACH_STATUS_MANUALLY_DETACHED)
   end
 end
 

lua/copilot/util.lua

@@ -3,6 +3,7 @@ local logger = require("copilot.logger")
 
 local M = {}
 VAR_ATTACH_STATUS = "copilot_lua_attach_status"
+VAR_PREVIOUS_FT = "copilot_lua_previous_ft"
 ATTACH_STATUS_MANUALLY_DETACHED = "manually detached"
 ATTACH_STATUS_FORCE_ATTACHED = "force attached"
 ATTACH_STATUS_ATTACHED = "attached"
@@ -172,4 +173,17 @@ function M.get_buffer_attach_status(bufnr)
   return (ok and result) or ATTACH_STATUS_NOT_YET_REQUESTED
 end
 
+---@param bufnr integer
+---@param filetype string
+function M.set_buffer_previous_ft(bufnr, filetype)
+  vim.api.nvim_buf_set_var(bufnr, VAR_PREVIOUS_FT, filetype)
+end
+
+---@param bufnr integer
+---@return string
+function M.get_buffer_previous_ft(bufnr)
+  local ok, result = pcall(vim.api.nvim_buf_get_var, bufnr, VAR_PREVIOUS_FT)
+  return (ok and result) or ""
+end
+
 return M

tests/test_client.lua

@@ -341,4 +341,19 @@ end
 --   u.expect_match(messages, ".*Online.*attached.*")
 -- end
 
+T["client()"]["saving file - will not yield URI not found error"] = function()
+  child.config.suggestion = child.config.suggestion .. "auto_trigger = true,"
+  child.configure_copilot()
+  child.type_keys("i", "123", "<Esc>", "o456", "<Esc>", "o7")
+  child.wait_for_suggestion()
+  child.type_keys("<Esc>")
+  child.lua("M.suggested = false")
+  child.cmd("w! tests/files/test.txt")
+  child.type_keys("a8")
+  child.wait_for_suggestion()
+  local messages = child.cmd_capture("messages")
+
+  u.expect_no_match(messages, "RPC.*Document for URI could not be found")
+end
+
 return T