UI tweaks.

- Hide diagnostics on client exit
- Stop insert on popup focus.
- Hide popup on insertchar (for signature_help)

runtime/lua/vim/lsp.lua

@@ -343,9 +343,19 @@ function lsp.start_client(config)
   function handlers.on_exit(code, signal)
     active_clients[client_id] = nil
     uninitialized_clients[client_id] = nil
-    for _, client_ids in pairs(all_buffer_active_clients) do
+    local active_buffers = {}
+    for bufnr, client_ids in pairs(all_buffer_active_clients) do
+      if client_ids[client_id] then
+        table.insert(active_buffers, bufnr)
+      end
       client_ids[client_id] = nil
     end
+    -- Buffer level cleanup
+    vim.schedule(function()
+      for _, bufnr in ipairs(active_buffers) do
+        util.buf_clear_diagnostics(bufnr)
+      end
+    end)
     if config.on_exit then
       pcall(config.on_exit, code, signal, client_id)
     end

runtime/lua/vim/lsp/buf.lua

@@ -51,7 +51,9 @@ local function focusable_preview(method, params, fn)
   do
     local win = find_window_by_var(method, bufnr)
     if win then
-      return api.nvim_set_current_win(win)
+      api.nvim_set_current_win(win)
+      api.nvim_command("stopinsert")
+      return
     end
   end
   return request(method, params, function(_, _, result, _)
@@ -234,7 +236,9 @@ end
 function M.signature_help()
   local params = util.make_position_params()
   focusable_preview('textDocument/signatureHelp', params, function(result)
-    if not (result and result.signatures and result.signatures[1]) then return end
+    if not (result and result.signatures and result.signatures[1]) then
+      return { 'No signature available' }
+    end
 
     -- TODO show empty popup when signatures is empty?
     local lines = signature_help_to_preview_contents(result)

runtime/lua/vim/lsp/util.lua

@@ -104,7 +104,7 @@ function M.apply_text_edits(text_edits, bufnr)
     local e = cleaned[i]
     local A = {e.A[1] - start_line, e.A[2]}
     local B = {e.B[1] - start_line, e.B[2]}
-    M.set_lines(lines, A, B, e.lines)
+    lines = M.set_lines(lines, A, B, e.lines)
   end
   if set_eol and #lines[#lines] == 0 then
     table.remove(lines)
@@ -340,7 +340,8 @@ function M.open_floating_preview(contents, filetype, opts)
   end
   api.nvim_buf_set_lines(floating_bufnr, 0, -1, true, contents)
   api.nvim_buf_set_option(floating_bufnr, 'modifiable', false)
-  api.nvim_command("autocmd CursorMoved,BufHidden <buffer> ++once lua pcall(vim.api.nvim_win_close, "..floating_winnr..", true)")
+  -- TODO make InsertCharPre disappearing optional?
+  api.nvim_command("autocmd CursorMoved,BufHidden,InsertCharPre <buffer> ++once lua pcall(vim.api.nvim_win_close, "..floating_winnr..", true)")
   return floating_bufnr, floating_winnr
 end