(mini.completion) Respect filterText from LSP response.

Details:
- Resolves
  #306 (comment).

lua/mini/completion.lua

@@ -243,7 +243,8 @@ MiniCompletion.config = {
     process_items = function(items, base)
       local res = vim.tbl_filter(function(item)
         -- Keep items which match the base and are not snippets
-        return vim.startswith(H.get_completion_word(item), base) and item.kind ~= 15
+        local text = item.filterText or H.get_completion_word(item)
+        return vim.startswith(text, base) and item.kind ~= 15
       end, items)
 
       table.sort(res, function(a, b) return (a.sortText or a.label) < (b.sortText or b.label) end)

tests/dir-completion/mock-months-lsp.lua

@@ -45,17 +45,22 @@ local construct_additionTextEdits = function(id, name)
 end
 
 local construct_textEdit = function(name)
-  local pos = _G.mock_textEdit_pos
-  if pos == nil then return end
+  if _G.mock_textEdit == nil then return end
+  local new_text, pos = _G.mock_textEdit.new_text, _G.mock_textEdit.pos
   return {
-    newText = '.' .. name,
+    newText = new_text(name),
     range = {
       start = { line = pos[1] - 1, character = pos[2] - 1 },
       ['end'] = { line = pos[1] - 1, character = pos[2] },
     },
   }
 end
 
+local construct_filterText = function(name)
+  if _G.mock_filterText == nil then return end
+  return _G.mock_filterText(name)
+end
+
 Months.requests = {
   ['textDocument/completion'] = function(params)
     local items = {}
@@ -65,8 +70,12 @@ Months.requests = {
       if vim.tbl_contains({ 'September', 'November' }, item.name) then
         res.additionalTextEdits = construct_additionTextEdits('completion', item.name)
       end
-      -- Mock `textEdit` as in `tsserver` when called after `.`
-      if vim.tbl_contains({ 'April', 'August' }, item.name) then res.textEdit = construct_textEdit(item.name) end
+
+      if vim.tbl_contains({ 'April', 'August' }, item.name) then
+        res.textEdit = construct_textEdit(item.name)
+        res.filterText = construct_filterText(item.name)
+      end
+
       table.insert(items, res)
     end
 

tests/test_completion.lua

@@ -471,15 +471,41 @@ end
 T['Manual completion']['prefers completion range from LSP response'] = function()
   set_lines({})
   type_keys('i', 'months.')
-  child.lua('_G.mock_textEdit_pos = vim.api.nvim_win_get_cursor(0)')
+  -- 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,
+  } ]])
   type_keys('<C-space>')
 
-  eq(get_completion(), { '.April', '.August' })
+  eq(get_completion('abbr'), { 'April', 'August' })
+  eq(get_completion('word'), { '.April', '.August' })
   type_keys('<C-n>', '<C-y>')
   eq(get_lines(), { 'months.April' })
   eq(get_cursor(), { 1, 12 })
 end
 
+T['Manual completion']['respects `filterText` from LSP response'] = function()
+  set_lines({})
+  type_keys('i', 'months.')
+  -- Mock `textEdit` and `filterText` as in `tsserver` when called after `.`
+  -- (see https://github.com/echasnovski/mini.nvim/issues/306#issuecomment-1602245446)
+  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' })
+  eq(get_completion('word'), { '[April]', '[August]' })
+  type_keys('<C-n>', '<C-y>')
+  eq(get_lines(), { 'months[April]' })
+  eq(get_cursor(), { 1, 13 })
+end
+
 T['Manual completion']['respects `vim.{g,b}.minicompletion_disable`'] = new_set({
   parametrize = { { 'g' }, { 'b' } },
 }, {