refactor(luasnip): wip

Update lua annotations using refactor branch
Fix `docTrig` replacement using Luasnip v2.4.1
Add initial support for choice nodes

Author: soifou

lua/blink/cmp/sources/snippets/luasnip.lua

@@ -1,5 +1,6 @@
 ---@type LuaSnip.API
 local luasnip
+local cmp = require('blink.cmp')
 local utils = require('blink.cmp.lib.utils')
 local text_edits = require('blink.cmp.lib.text_edits')
 local kind_snippet = require('blink.cmp.types').CompletionItemKind.Snippet
@@ -26,21 +27,55 @@ local function add_luasnip_callback(snippet, event, callback)
   snippet.callbacks[-1][events[event]] = callback
 end
 
+---@param snippet LuaSnip.Snippet
+local function regex_callback(snippet, docTrig)
+  if #snippet.insert_nodes == 0 then
+    snippet.insert_nodes[0].static_text[1] = docTrig
+    return
+  end
+
+  local matches = { string.match(docTrig, snippet.trigger) }
+  for i, match in ipairs(matches) do
+    local idx = i ~= #matches and i or 0
+    snippet.insert_nodes[idx].static_text[1] = match
+  end
+end
+
+---@param snippet LuaSnip.Snippet
+local function choice_callback(snippet)
+  local events = require('luasnip.util.events')
+  local types = require('luasnip.util.types')
+
+  for _, node in ipairs(snippet.insert_nodes) do
+    if node.type == types.choiceNode then
+      node.node_callbacks = {
+        [events.enter] = function(
+          n --[[@cast n LuaSnip.ChoiceNode]]
+        )
+          vim.schedule(function()
+            local index = utils.find_idx(n.choices, function(choice) return choice == n.active_choice end)
+            n:set_text_raw({ '' }) -- NOTE: Available since v2.4.1
+            cmp.show({ initial_selected_item_idx = index, providers = { 'snippets' } })
+          end)
+        end,
+        [events.change_choice] = function()
+          vim.schedule(function() luasnip.jump(1) end)
+        end,
+        [events.leave] = function() vim.schedule(cmp.hide) end,
+      }
+    end
+  end
+end
+
 ---@param snippet LuaSnip.Snippet
 ---@return string?
 local function get_insert_text(snippet)
   local res = {}
   for _, node in ipairs(snippet.nodes) do
-    ---@cast node LuaSnip.Node
-    -- TODO: How to know the node type? Would be nice to handle the others as well
-    -- textNodes
-    if type(node.static_text) == 'table' then res[#res + 1] = table.concat(node.static_text, '\n') end
+    if node.static_text then res[#res + 1] = table.concat(node:get_static_text(), '\n') end
   end
-
   -- Fallback
   if #res == 1 then
-    -- Prefer docTrig over trigger
-    ---@diagnostic disable-next-line: undefined-field
     if snippet.docTrig then return snippet.docTrig end
     return snippet.trigger
   end
@@ -97,7 +132,24 @@ function source:get_completions(ctx, callback)
   --- @type blink.cmp.CompletionItem[]
   local items = {}
 
-  -- Gather snippets from relevant filetypes, including extensions
+  if luasnip.choice_active() then
+    ---@type LuaSnip.ChoiceNode
+    local active_choice = require('luasnip.session').active_choice_nodes[ctx.bufnr]
+    for i, choice in ipairs(active_choice.choices) do
+      local text = choice:get_static_text()[1]
+      table.insert(items, {
+        label = text,
+        kind = kind_snippet,
+        insertText = text,
+        insertTextFormat = vim.lsp.protocol.InsertTextFormat.PlainText,
+        data = { snip_id = active_choice.parent.snippet.id, choice_index = i },
+      })
+    end
+    callback({ is_incomplete_forward = false, is_incomplete_backward = false, items = items })
+    return
+  end
+
+  -- Else, gather snippets from relevant filetypes, including extensions
   for _, ft in ipairs(require('luasnip.util.util').get_snippet_filetypes()) do
     if self.items_cache[ft] and #self.items_cache[ft] > 0 then
       for _, item in ipairs(self.items_cache[ft]) do
@@ -114,7 +166,7 @@ function source:get_completions(ctx, callback)
     if self.opts.show_autosnippets then
       local autosnippets = luasnip.get_snippets(ft, { type = 'autosnippets' })
       for _, s in ipairs(autosnippets) do
-        add_luasnip_callback(s, 'enter', require('blink.cmp').hide)
+        add_luasnip_callback(s, 'enter', cmp.hide)
       end
       snippets = utils.shallow_copy(snippets)
       vim.list_extend(snippets, autosnippets)
@@ -180,11 +232,9 @@ function source:resolve(item, callback)
   if type(detail) == 'table' then detail = table.concat(detail, '\n') end
   resolved_item.detail = detail
 
-  ---@diagnostic disable-next-line: undefined-field
   if snip.dscr then
     resolved_item.documentation = {
       kind = 'markdown',
-      ---@diagnostic disable-next-line: undefined-field
       value = table.concat(vim.lsp.util.convert_input_to_markdown_lines(snip.dscr), '\n'),
     }
   end
@@ -195,34 +245,26 @@ end
 ---@param ctx blink.cmp.Context
 ---@param item blink.cmp.CompletionItem
 function source:execute(ctx, item)
+  if item.data.choice_index then
+    luasnip.set_choice(item.data.choice_index)
+    return
+  end
+
   local snip = luasnip.get_id_snippet(item.data.snip_id)
 
-  -- if trigger is a pattern, expand "pattern" instead of actual snippet
-  ---@diagnostic disable-next-line: undefined-field
   if snip.regTrig then
-    ---@diagnostic disable-next-line: undefined-field
     local docTrig = self.opts.prefer_doc_trig and snip.docTrig
-    snip = snip:get_pattern_expand_helper() --[[@as LuaSnip.Snippet]]
-
-    if docTrig then
-      add_luasnip_callback(snip, 'pre_expand', function(snip, _)
-        if #snip.insert_nodes == 0 then
-          snip.insert_nodes[0].static_text = { docTrig }
-        else
-          local matches = { string.match(docTrig, snip.trigger) }
-          for i, match in ipairs(matches) do
-            local idx = i ~= #matches and i or 0
-            snip.insert_nodes[idx].static_text = { match }
-          end
-        end
-      end)
-    end
+    snip = snip:get_pattern_expand_helper()
+    if docTrig then add_luasnip_callback(snip, 'pre_expand', function(s) regex_callback(s, docTrig) end) end
+  else
+    add_luasnip_callback(snip, 'pre_expand', choice_callback)
   end
 
   local cursor = ctx.get_cursor() --[[@as LuaSnip.BytecolBufferPosition]]
   cursor[1] = cursor[1] - 1
 
   local range = text_edits.get_from_item(item).range
+
   ---@type LuaSnip.BufferRegion
   local clear_region = {
     from = { range.start.line, range.start.character },
@@ -233,15 +275,12 @@ function source:execute(ctx, item)
   local line_to_cursor = line:sub(1, cursor[2])
   local range_text = line:sub(range.start.character + 1, cursor[2])
 
-  ---@type LuaSnip.Opts.SnipExpandExpandParams?
   local expand_params = snip:matches(line_to_cursor, {
-    fallback_match = range_text ~= line_to_cursor and range_text,
+    fallback_match = range_text ~= line_to_cursor and range_text or nil,
   })
 
   if expand_params ~= nil then
-    ---@diagnostic disable-next-line: undefined-field
     if expand_params.clear_region ~= nil then
-      ---@diagnostic disable-next-line: undefined-field
       clear_region = expand_params.clear_region
     elseif expand_params.trigger ~= nil then
       clear_region.from = { cursor[1], cursor[2] - #expand_params.trigger }