fix: wait for all LSPs to respond before showing

Closes #691

lua/blink/cmp/sources/lib/provider/list.lua

@@ -66,6 +66,8 @@ function list.new(provider, context, on_items, opts)
 end
 
 function list:append(response)
+  if self.has_completed and #response.items == 0 then return end
+
   if not self.has_completed then
     self.has_completed = true
     self.is_incomplete_backward = response.is_incomplete_backward

lua/blink/cmp/sources/lsp/completion.lua

@@ -0,0 +1,71 @@
+local async = require('blink.cmp.lib.async')
+local known_defaults = {
+  'commitCharacters',
+  'insertTextFormat',
+  'insertTextMode',
+  'data',
+}
+local CompletionTriggerKind = vim.lsp.protocol.CompletionTriggerKind
+
+local completion = {}
+
+function completion.get_completion_for_client(client, context)
+  return async.task.new(function(resolve)
+    local params = vim.lsp.util.make_position_params(0, client.offset_encoding)
+    params.context = {
+      triggerKind = context.trigger.kind == 'trigger_character' and CompletionTriggerKind.TriggerCharacter
+        or CompletionTriggerKind.Invoked,
+    }
+    if context.trigger.kind == 'trigger_character' then params.context.triggerCharacter = context.trigger.character end
+
+    local _, request_id = client.request('textDocument/completion', params, function(err, result)
+      if err or result == nil then
+        resolve({ is_incomplete_forward = false, is_incomplete_backward = false, items = {} })
+        return
+      end
+
+      local items = result.items or result
+      local default_edit_range = result.itemDefaults and result.itemDefaults.editRange
+      for _, item in ipairs(items) do
+        item.client_id = client.id
+
+        -- score offset for deprecated items
+        -- todo: make configurable
+        if item.deprecated or (item.tags and vim.tbl_contains(item.tags, 1)) then item.score_offset = -2 end
+
+        -- set defaults
+        for key, value in pairs(result.itemDefaults or {}) do
+          if vim.tbl_contains(known_defaults, key) then item[key] = item[key] or value end
+        end
+        if default_edit_range and item.textEdit == nil then
+          local new_text = item.textEditText or item.insertText or item.label
+          if default_edit_range.replace ~= nil then
+            item.textEdit = {
+              replace = default_edit_range.replace,
+              insert = default_edit_range.insert,
+              newText = new_text,
+            }
+          else
+            item.textEdit = {
+              range = result.itemDefaults.editRange,
+              newText = new_text,
+            }
+          end
+        end
+      end
+
+      resolve({
+        is_incomplete_forward = result.isIncomplete or false,
+        is_incomplete_backward = true,
+        items = items,
+      })
+    end)
+
+    -- cancellation function
+    return function()
+      if request_id ~= nil then client.cancel_request(request_id) end
+    end
+  end)
+end
+
+return completion