fix(completion)!: update default_process_items to use proper fields

Details:
- Use filterText>label instead of textEdit.newText>insertText>label.
  This is more aligned with LSP specification.

Author: echasnovski

CHANGELOG.md

@@ -43,6 +43,7 @@
     - Show `detail` highlighted as buffer's language at the start of info window, but only if `detail` provides information not already present in `documentation`. It was previously used as extra text in the popup menu (via `menu` field), but this doesn't quite follow LSP specification: `detail` and `documentation` fields can be delayed up until `completionItem/resolve` request which implies they should be treated similarly.
     - Show `labelDetails` as a part of the popup menu via `menu` completion item field.
 - BREAKING: prefer to not use functions as default config values. In particular, for `lsp_completion.process_items` (use `nil` with explicit fallback) and `fallback_action` (use `'<C-n>'`). This should not have any user facing effects and marked as breaking only because a structure of a default config has changed to be more aligned with other modules.
+- BREAKING: update `default_process_items()` to only use `filterText` and `label` item fields during matching (instead of `textEdit.newText`, `insertText`, and `label` as before). This is more aligned with LSP specification.
 
 ## mini.doc
 

lua/mini/completion.lua

@@ -467,11 +467,7 @@ end
 ---
 ---@return table Array of processed items from LSP response.
 MiniCompletion.default_process_items = function(items, base)
-  local res = vim.tbl_filter(
-    function(item) return vim.startswith(item.filterText or H.get_completion_word(item), base) end,
-    items
-  )
-
+  local res = vim.tbl_filter(function(x) return vim.startswith(x.filterText or x.label, base) end, items)
   res = vim.deepcopy(res)
   table.sort(res, function(a, b) return (a.sortText or a.label) < (b.sortText or b.label) end)
 

tests/test_completion.lua

@@ -767,11 +767,14 @@ end
 T['Manual completion']['prefers completion range from LSP response'] = function()
   set_lines({})
   type_keys('i', 'months.')
-  -- Mock `textEdit` as in `tsserver` when called after `.`
-  child.lua([[_G.mock_textEdit = {
-    pos = vim.api.nvim_win_get_cursor(0),
-    new_text = function(name) return '.' .. name end,
-  } ]])
+  -- Mock `textEdit`+`filterText` as in `tsserver` when called after `.`
+  child.lua([[
+    _G.mock_textEdit = {
+      pos = vim.api.nvim_win_get_cursor(0),
+      new_text = function(name) return '.' .. name end,
+    }
+    _G.mock_filterText = function(name) return '.' .. name end
+  ]])
   type_keys('<C-space>')
 
   eq(get_completion('abbr'), { 'April', 'August' })