6 files changed, 104 insertions, 22 deletions

diff --git a/runtime/lua/vim/lsp.lua b/runtime/lua/vim/lsp.lua
index 4c453df3f6..563ffc479e 100644
--- a/runtime/lua/vim/lsp.lua
+++ b/runtime/lua/vim/lsp.lua
@@ -38,13 +38,13 @@ lsp._request_name_to_capability = {
   ['textDocument/declaration'] = 'declaration';
   ['textDocument/typeDefinition'] = 'type_definition';
   ['textDocument/documentSymbol'] = 'document_symbol';
-  ['textDocument/workspaceSymbol'] = 'workspace_symbol';
   ['textDocument/prepareCallHierarchy'] = 'call_hierarchy';
   ['textDocument/rename'] = 'rename';
   ['textDocument/codeAction'] = 'code_action';
   ['textDocument/codeLens'] = 'code_lens';
   ['codeLens/resolve'] = 'code_lens_resolve';
   ['workspace/executeCommand'] = 'execute_command';
+  ['workspace/symbol'] = 'workspace_symbol';
   ['textDocument/references'] = 'find_references';
   ['textDocument/rangeFormatting'] = 'document_range_formatting';
   ['textDocument/formatting'] = 'document_formatting';
@@ -850,20 +850,23 @@ do
     end
 
     util.buf_versions[bufnr] = changedtick
-    -- Lazy initialize these because clients may not even need them.
-    local incremental_changes = once(function(client)
+
+    local incremental_changes = function(client)
       local lines = nvim_buf_get_lines(bufnr, 0, -1, true)
       local startline =  math.min(firstline + 1, math.min(#client._cached_buffers[bufnr], #lines))
       local endline =  math.min(-(#lines - new_lastline), -1)
-      local incremental_change = vim.lsp.util.compute_diff(client._cached_buffers[bufnr], lines, startline, endline)
+      local incremental_change = vim.lsp.util.compute_diff(
+        client._cached_buffers[bufnr], lines, startline, endline, client.offset_encoding or "utf-16")
       client._cached_buffers[bufnr] = lines
       return incremental_change
-    end)
+    end
+
     local full_changes = once(function()
       return {
         text = buf_get_full_text(bufnr);
       };
     end)
+
     local uri = vim.uri_from_bufnr(bufnr)
     for_each_buffer_client(bufnr, function(client)
       local allow_incremental_sync = if_nil(client.config.flags.allow_incremental_sync, true)
@@ -928,10 +931,25 @@ function lsp.buf_attach_client(bufnr, client_id)
     all_buffer_active_clients[bufnr] = buffer_client_ids
 
     local uri = vim.uri_from_bufnr(bufnr)
-    nvim_command(string.format("autocmd BufWritePost <buffer=%d> lua vim.lsp._text_document_did_save_handler(0)", bufnr))
+    local buf_did_save_autocommand = [=[
+      augroup lsp_c_%d_b_%d_did_save
+        au!
+        au BufWritePost <buffer=%d> lua vim.lsp._text_document_did_save_handler(0)
+      augroup END
+    ]=]
+    vim.api.nvim_exec(string.format(buf_did_save_autocommand, client_id, bufnr, bufnr), false)
     -- First time, so attach and set up stuff.
     vim.api.nvim_buf_attach(bufnr, false, {
       on_lines = text_document_did_change_handler;
+      on_reload = function()
+        local params = { textDocument = { uri = uri; } }
+        for_each_buffer_client(bufnr, function(client, _)
+          if client.resolved_capabilities.text_document_open_close then
+            client.notify('textDocument/didClose', params)
+          end
+          text_document_did_open_handler(bufnr, client)
+        end)
+      end;
       on_detach = function()
         local params = { textDocument = { uri = uri; } }
         for_each_buffer_client(bufnr, function(client, _)
diff --git a/runtime/lua/vim/lsp/rpc.lua b/runtime/lua/vim/lsp/rpc.lua
index 4e2dd7c8e8..1aa8326514 100644
--- a/runtime/lua/vim/lsp/rpc.lua
+++ b/runtime/lua/vim/lsp/rpc.lua
@@ -315,8 +315,10 @@ local function start(cmd, cmd_args, dispatchers, extra_spawn_params)
     dispatchers = { dispatchers, 't', true };
   }
 
-  if not (vim.fn.executable(cmd) == 1) then
-    error(string.format("The given command %q is not executable.", cmd))
+  if extra_spawn_params and extra_spawn_params.cwd then
+      assert(is_dir(extra_spawn_params.cwd), "cwd must be a directory")
+  elseif not (vim.fn.executable(cmd) == 1) then
+      error(string.format("The given command %q is not executable.", cmd))
   end
   if dispatchers then
     local user_dispatchers = dispatchers
@@ -370,9 +372,6 @@ local function start(cmd, cmd_args, dispatchers, extra_spawn_params)
     }
     if extra_spawn_params then
       spawn_params.cwd = extra_spawn_params.cwd
-      if spawn_params.cwd then
-        assert(is_dir(spawn_params.cwd), "cwd must be a directory")
-      end
       spawn_params.env = env_merge(extra_spawn_params.env)
     end
     handle, pid = uv.spawn(cmd, spawn_params, onexit)
diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index a75ab37508..ec1131ae1f 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -357,8 +357,11 @@ end
 --- Returns the range table for the difference between old and new lines
 --@param old_lines table list of lines
 --@param new_lines table list of lines
+--@param start_line_idx int line to begin search for first difference
+--@param end_line_idx int line to begin search for last difference
+--@param offset_encoding string encoding requested by language server
 --@returns table start_line_idx and start_col_idx of range
-function M.compute_diff(old_lines, new_lines, start_line_idx, end_line_idx)
+function M.compute_diff(old_lines, new_lines, start_line_idx, end_line_idx, offset_encoding)
   local start_line, start_char = first_difference(old_lines, new_lines, start_line_idx)
   local end_line, end_char = last_difference(vim.list_slice(old_lines, start_line, #old_lines),
       vim.list_slice(new_lines, start_line, #new_lines), start_char, end_line_idx)
@@ -373,10 +376,19 @@ function M.compute_diff(old_lines, new_lines, start_line_idx, end_line_idx)
     adj_end_char = #old_lines[#old_lines + end_line + 1] + end_char + 1
   end
 
+  local _
+  if offset_encoding == "utf-16" then
+    _, start_char = vim.str_utfindex(old_lines[start_line], start_char - 1)
+    _, end_char = vim.str_utfindex(old_lines[#old_lines + end_line + 1], adj_end_char)
+  else
+    start_char = start_char - 1
+    end_char = adj_end_char
+  end
+
   local result = {
     range = {
-      start = { line = start_line - 1, character = start_char - 1},
-      ["end"] = { line = adj_end_line, character = adj_end_char}
+      start = { line = start_line - 1, character = start_char},
+      ["end"] = { line = adj_end_line, character = end_char}
     },
     text = text,
     rangeLength = length + 1,
diff --git a/runtime/lua/vim/treesitter.lua b/runtime/lua/vim/treesitter.lua
index 64a5ba1fd8..cac0ab864b 100644
--- a/runtime/lua/vim/treesitter.lua
+++ b/runtime/lua/vim/treesitter.lua
@@ -10,6 +10,8 @@ local parsers = {}
 
 local M = vim.tbl_extend("error", query, language)
 
+M.language_version = vim._ts_get_language_version()
+
 setmetatable(M, {
   __index = function (t, k)
       if k == "highlighter" then
diff --git a/runtime/lua/vim/treesitter/highlighter.lua b/runtime/lua/vim/treesitter/highlighter.lua
index 9af6008700..fe7e1052c9 100644
--- a/runtime/lua/vim/treesitter/highlighter.lua
+++ b/runtime/lua/vim/treesitter/highlighter.lua
@@ -12,6 +12,16 @@ TSHighlighterQuery.__index = TSHighlighterQuery
 
 local ns = a.nvim_create_namespace("treesitter/highlighter")
 
+local _default_highlights = {}
+local _link_default_highlight_once = function(from, to)
+  if not _default_highlights[from] then
+    _default_highlights[from] = true
+    vim.cmd(string.format("highlight default link %s %s", from, to))
+  end
+
+  return from
+end
+
 -- These are conventions defined by nvim-treesitter, though it
 -- needs to be user extensible also.
 TSHighlighter.hl_map = {
@@ -70,9 +80,12 @@ function TSHighlighterQuery.new(lang, query_string)
 
   self.hl_cache = setmetatable({}, {
     __index = function(table, capture)
-      local hl = self:get_hl_from_capture(capture)
-      rawset(table, capture, hl)
+      local hl, is_vim_highlight = self:_get_hl_from_capture(capture)
+      if not is_vim_highlight then
+        hl = _link_default_highlight_once(lang .. hl, hl)
+      end
 
+      rawset(table, capture, hl)
       return hl
     end
   })
@@ -90,16 +103,16 @@ function TSHighlighterQuery:query()
   return self._query
 end
 
-function TSHighlighterQuery:get_hl_from_capture(capture)
+--- Get the hl from capture.
+--- Returns a tuple { highlight_name: string, is_builtin: bool }
+function TSHighlighterQuery:_get_hl_from_capture(capture)
   local name = self._query.captures[capture]
 
   if is_highlight_name(name) then
     -- From "Normal.left" only keep "Normal"
-    return vim.split(name, '.', true)[1]
+    return vim.split(name, '.', true)[1], true
   else
-    -- Default to false to avoid recomputing
-    local hl = TSHighlighter.hl_map[name]
-    return hl and a.nvim_get_hl_id_by_name(hl) or 0
+    return TSHighlighter.hl_map[name] or name, false
   end
 end
 
diff --git a/runtime/lua/vim/treesitter/query.lua b/runtime/lua/vim/treesitter/query.lua
index 8b94348994..188ec94a6a 100644
--- a/runtime/lua/vim/treesitter/query.lua
+++ b/runtime/lua/vim/treesitter/query.lua
@@ -8,10 +8,23 @@ Query.__index = Query
 
 local M = {}
 
+local function dedupe_files(files)
+  local result = {}
+  local seen = {}
+
+  for _, path in ipairs(files) do
+    if not seen[path] then
+      table.insert(result, path)
+      seen[path] = true
+    end
+  end
+
+  return result
+end
 
 function M.get_query_files(lang, query_name, is_included)
   local query_path = string.format('queries/%s/%s.scm', lang, query_name)
-  local lang_files = a.nvim_get_runtime_file(query_path, true)
+  local lang_files = dedupe_files(a.nvim_get_runtime_file(query_path, true))
 
   if #lang_files == 0 then return {} end
 
@@ -77,6 +90,27 @@ local function new_match_metadata()
   return setmetatable({}, match_metatable)
 end
 
+--- The explicitly set queries from |vim.treesitter.query.set_query()|
+local explicit_queries = setmetatable({}, {
+  __index = function(t, k)
+    local lang_queries = {}
+    rawset(t, k, lang_queries)
+
+    return lang_queries
+  end,
+})
+
+--- Sets the runtime query {query_name} for {lang}
+---
+--- This allows users to override any runtime files and/or configuration
+--- set by plugins.
+---@param lang string: The language to use for the query
+---@param query_name string: The name of the query (i.e. "highlights")
+---@param text string: The query text (unparsed).
+function M.set_query(lang, query_name, text)
+  explicit_queries[lang][query_name] = M.parse_query(lang, text)
+end
+
 --- Returns the runtime query {query_name} for {lang}.
 --
 -- @param lang The language to use for the query
@@ -84,6 +118,10 @@ end
 --
 -- @return The corresponding query, parsed.
 function M.get_query(lang, query_name)
+  if explicit_queries[lang][query_name] then
+    return explicit_queries[lang][query_name]
+  end
+
   local query_files = M.get_query_files(lang, query_name)
   local query_string = read_query_files(query_files)