feat(completion): add support for item defaults

Author: echasnovski

CHANGELOG.md

@@ -38,6 +38,7 @@
 - FEATURE: both info and signature help windows now use tree-sitter highlighting:
     - Info window uses "markdown" parser (works best on Neovim>=0.10 as its parser is built-in). Special markdown characters are concealed (i.e. hidden) which might result into seemingly unnecessary whitespace as dimensions are computed not accounting for that.
     - Signature help uses same parser as in current filetype.
+- FEATURE: add support for item defaults in `CompletionList` response.
 - BREAKING FEATURE: rework how LSP completion items are converted to Neovim's completion items:
     - 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.

lua/mini/completion.lua

@@ -427,9 +427,11 @@ MiniCompletion.completefunc_lsp = function(findstart, base)
     process_items = process_items or MiniCompletion.default_process_items
     local words = H.process_lsp_response(H.completion.lsp.result, function(response, client_id)
       is_incomplete = is_incomplete or response.isIncomplete
-      -- Response can be `CompletionList` with 'items' field or `CompletionItem[]`
+      -- Response can be `CompletionList` with 'items' field plus their
+      -- defaults or `CompletionItem[]`
       local items = H.table_get(response, { 'items' }) or response
       if type(items) ~= 'table' then return {} end
+      items = H.apply_item_defaults(items, response.itemDefaults)
       items = process_items(items, base)
       return H.lsp_completion_response_items_to_complete_items(items, client_id)
     end)
@@ -977,6 +979,30 @@ H.make_completion_request = function()
   H.completion.lsp.cancel_fun = cancel_fun
 end
 
+H.apply_item_defaults = function(items, defaults)
+  if type(defaults) ~= 'table' then return items end
+
+  local edit_range = defaults.editRange
+  local has_edit_range = type(edit_range) == 'table'
+  for _, item in ipairs(items) do
+    item.commitCharacters = item.commitCharacters or defaults.commitCharacters
+    item.data = item.data or defaults.data
+    item.insertTextFormat = item.insertTextFormat or defaults.insertTextFormat
+    item.insertTextMode = item.insertTextMode or defaults.insertTextMode
+    if has_edit_range then
+      item.textEdit = item.textEdit or {}
+      -- Infer new text from `item.textEditText` designed for default edit case
+      item.textEdit.newText = item.textEdit.newText or item.textEditText or item.label
+      -- Default `editRange` is range (start+end) or insert+replace ranges
+      item.textEdit.start = item.textEdit.start or edit_range.start
+      item.textEdit['end'] = item.textEdit['end'] or edit_range['end']
+      item.textEdit.insert = item.textEdit.insert or edit_range.insert
+      item.textEdit.replace = item.textEdit.replace or edit_range.replace
+    end
+  end
+  return items
+end
+
 -- Source:
 -- https://microsoft.github.io/language-server-protocol/specifications/specification-3-14/#textDocument_completion
 H.lsp_completion_response_items_to_complete_items = function(items, client_id)

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

@@ -123,10 +123,12 @@ Months.requests = {
 
       if item.name == 'April' then
         res.textEdit = construct_textEdit(item.name, 'InsertReplaceEdit')
+        res.textEditText = _G.mock_itemdefaults ~= nil and 'New April' or nil
         res.filterText = construct_filterText(item.name)
       end
       if item.name == 'August' then
         res.textEdit = construct_textEdit(item.name, 'textEdit')
+        res.textEditText = _G.mock_itemdefaults ~= nil and 'New August' or nil
         res.filterText = construct_filterText(item.name)
       end
 
@@ -136,7 +138,7 @@ Months.requests = {
     -- Mock incomplete computation
     if _G.mock_isincomplete then items = vim.list_slice(items, 1, 6) end
 
-    return { { result = { items = items, isIncomplete = _G.mock_isincomplete } } }
+    return { { result = { items = items, isIncomplete = _G.mock_isincomplete, itemDefaults = _G.mock_itemdefaults } } }
   end,
 
   ['completionItem/resolve'] = function(params)

tests/test_completion.lua

@@ -777,6 +777,68 @@ T['Manual completion']['respects `labelDetails` from LSP response'] = function()
   child.expect_screenshot()
 end
 
+T['Manual completion']['respects `itemDefaults` from LSP response'] = function()
+  local format_snippet = child.lua_get('vim.lsp.protocol.InsertTextFormat.Snippet')
+  child.lua([[
+    MiniCompletion.config.lsp_completion.process_items = function(items, _)
+      _G.latest_items = vim.deepcopy(items)
+      return items
+    end
+  ]])
+
+  child.lua([[
+    _G.mock_itemdefaults = {
+      commitCharacters = { ')' },
+      data = { hello = 'world' },
+      insertTextFormat = vim.lsp.protocol.InsertTextFormat.Snippet,
+      insertTextMode = 1,
+    }
+  ]])
+
+  -- Mock with `editRange` as regular `Range`
+  local edit_range = { start = { line = 0, character = 0 }, ['end'] = { line = 0, character = 1 } }
+  child.lua('_G.mock_itemdefaults.editRange = ' .. vim.inspect(edit_range))
+
+  set_lines({})
+  type_keys('i', '<C-Space>')
+
+  local items = child.lua_get('_G.latest_items')
+  for _, item in ipairs(items) do
+    eq(item.commitCharacters, { ')' })
+    eq(item.data, { hello = 'world' })
+    eq(item.insertTextFormat, format_snippet)
+    eq(item.insertTextMode, 1)
+
+    eq(item.textEdit.newText, item.textEditText or item.label)
+    eq(item.textEdit.start, edit_range.start)
+    eq(item.textEdit['end'], edit_range['end'])
+  end
+  type_keys('<C-e>')
+  child.lua('_G.latest_items = nil')
+
+  -- Mock with `editRange` as isnert+replace ranges and partial default data
+  child.lua('_G.mock_itemdefaults.data = nil')
+  edit_range = {
+    replace = { start = { line = 0, character = 0 }, ['end'] = { line = 0, character = 1 } },
+    insert = { start = { line = 0, character = 1 }, ['end'] = { line = 0, character = 2 } },
+  }
+  child.lua('_G.mock_itemdefaults.editRange = ' .. vim.inspect(edit_range))
+
+  type_keys('<C-Space>')
+  items = child.lua_get('_G.latest_items')
+  for _, item in ipairs(items) do
+    eq(item.commitCharacters, { ')' })
+    eq(item.data, nil)
+    eq(item.insertTextFormat, format_snippet)
+    eq(item.insertTextMode, 1)
+
+    eq(item.textEdit.newText, item.textEditText or item.label)
+    eq(item.textEdit.insert, edit_range.insert)
+    eq(item.textEdit.replace, edit_range.replace)
+  end
+  type_keys('<C-e>')
+end
+
 T['Manual completion']['respects `kind_hlgroup` as item field'] = function()
   if child.fn.has('nvim-0.11') == 0 then MiniTest.skip('Kind highlighting is available on Neovim>=0.11') end
   child.set_size(10, 40)