Merge #15667 release-0.5: backports

19 files changed, 712 insertions, 139 deletions

diff --git a/BSDmakefile b/BSDmakefile
index 93b7dc7f3d..f81223bafa 100644
--- a/BSDmakefile
+++ b/BSDmakefile
@@ -1,4 +1,4 @@
 .DONE:
-	@echo "Please use GNU Make (gmake) to build neovim"
+	@echo "Use GNU Make (gmake) to build neovim"
 .DEFAULT:
-	@echo "Please use GNU Make (gmake) to build neovim"
+	@echo "Use GNU Make (gmake) to build neovim"
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 27fd2b97bb..24b8cf60ed 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -28,10 +28,10 @@ Reporting problems
 Developer guidelines
 --------------------
 
-- Nvim contributors should read `:help dev`.
-- External UI developers should read `:help dev-ui`.
-- API client developers should read `:help dev-api-client`.
-- Nvim developers are _strongly encouraged_ to install `ninja` for faster builds.
+- Read `:help dev` if you are working on Nvim core.
+- Read `:help dev-ui` if you are developing a UI.
+- Read `:help dev-api-client` if you are developing an API client.
+- Install `ninja` for faster builds of Nvim.
   ```
   sudo apt-get install ninja-build
   make distclean
diff --git a/cmake/RunTests.cmake b/cmake/RunTests.cmake
index f000004aec..e2096dc06c 100644
--- a/cmake/RunTests.cmake
+++ b/cmake/RunTests.cmake
@@ -49,6 +49,10 @@ endif()
 set(ENV{TMPDIR} "${BUILD_DIR}/Xtest_tmpdir/${TEST_PATH}")
 execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory $ENV{TMPDIR})
 
+if(NOT DEFINED ENV{TEST_TIMEOUT} OR "$ENV{TEST_TIMEOUT}" STREQUAL "")
+  set(ENV{TEST_TIMEOUT} 1200)
+endif()
+
 set(ENV{SYSTEM_NAME} ${CMAKE_HOST_SYSTEM_NAME})  # used by test/helpers.lua.
 execute_process(
   COMMAND ${BUSTED_PRG} -v -o test.busted.outputHandlers.${BUSTED_OUTPUT_TYPE}
@@ -58,6 +62,7 @@ execute_process(
     --lpath=?.lua
     ${BUSTED_ARGS}
     ${TEST_PATH}
+  TIMEOUT $ENV{TEST_TIMEOUT}
   WORKING_DIRECTORY ${WORKING_DIR}
   ERROR_VARIABLE err
   RESULT_VARIABLE res
diff --git a/runtime/doc/deprecated.txt b/runtime/doc/deprecated.txt
index 3b5287ee44..36e6cc89e6 100644
--- a/runtime/doc/deprecated.txt
+++ b/runtime/doc/deprecated.txt
@@ -54,6 +54,8 @@ Functions ~
 			without stopping the job. Use chanclose(id) to close
 			any socket.
 
+Lua ~
+*vim.register_keystroke_callback()* Use |vim.on_key()| instead.
 
 Modifiers ~
 *cpo-<*
diff --git a/runtime/doc/develop.txt b/runtime/doc/develop.txt
index aec0178da2..401ad0e536 100644
--- a/runtime/doc/develop.txt
+++ b/runtime/doc/develop.txt
@@ -127,14 +127,20 @@ Sometimes a GUI or other application may want to force a provider to
 
 DOCUMENTATION						*dev-doc*
 
-- Do not prefix help tags with "nvim-". Use |vim_diff.txt| to document
-  differences from Vim; no other distinction is necessary.
-- If a Vim feature is removed, delete its help section and move its tag to
-  |vim_diff.txt|.
-- Move deprecated features to |deprecated.txt|.
+- "Just say it". Avoid mushy, colloquial phrasing in all documentation
+  (docstrings, user manual, website materials, newsletters, …). Don't mince
+  words. Personality and flavor, used sparingly, are welcome--but in general,
+  optimize for the reader's time and energy: be "precise yet concise".
+    - Prefer the active voice: "Foo does X", not "X is done by Foo".
+- Vim differences:
+    - Do not prefix help tags with "nvim-". Use |vim_diff.txt| to catalog
+      differences from Vim; no other distinction is necessary.
+    - If a Vim feature is removed, delete its help section and move its tag to
+      |vim_diff.txt|.
+- Mention deprecated features in |deprecated.txt| and delete their old doc.
 - Use consistent language.
-    - "terminal" in a help tag always means "the embedded terminal emulator", not
-      "the user host terminal".
+    - "terminal" in a help tag always means "the embedded terminal emulator",
+      not "the user host terminal".
     - Use "tui-" to prefix help tags related to the host terminal, and "TUI"
       in prose if possible.
 - Docstrings: do not start parameter descriptions with "The" or "A" unless it
@@ -222,13 +228,13 @@ LUA							*dev-lua*
 
 - Keep the core Lua modules |lua-stdlib| simple. Avoid elaborate OOP or
   pseudo-OOP designs. Plugin authors just want functions to call, they don't
-  want to learn a big, fancy inheritance hierarchy. So we should avoid complex
-  objects: tables are usually better.
+  want to learn a big, fancy inheritance hierarchy. Thus avoid specialized
+  objects; tables or values are usually better.
 
 
 API							*dev-api*
 
-Use this template to name new API functions:
+Use this template to name new RPC |API| functions:
     nvim_{thing}_{action}_{arbitrary-qualifiers}
 
 If the function acts on an object then {thing} is the name of that object
@@ -356,4 +362,19 @@ External UIs are expected to implement these common features:
   published in this event. See also "mouse_on", "mouse_off".
 
 
+NAMING							*dev-naming*
+
+Naming is important. Consistent naming in the API and UI helps both users and
+developers discover and intuitively understand related concepts ("families"),
+and reduces cognitive burden. Discoverability encourages code re-use and
+likewise avoids redundant, overlapping mechanisms, which reduces code
+surface-area, and thereby minimizes bugs...
+
+Naming conventions ~
+
+Use the "on_" prefix to name event handlers and also the interface for
+"registering" such handlers (on_key). The dual nature is acceptable to avoid
+a confused collection of naming conventions for these related concepts.
+
+
  vim:tw=78:ts=8:noet:ft=help:norl:
diff --git a/runtime/doc/lua.txt b/runtime/doc/lua.txt
index fd1bedd8ef..16d2fcd424 100644
--- a/runtime/doc/lua.txt
+++ b/runtime/doc/lua.txt
@@ -572,11 +572,11 @@ If you want to exclude visual selections from highlighting on yank, use
 vim.highlight.on_yank({opts})                         *vim.highlight.on_yank()*
         Highlights the yanked text. The fields of the optional dict {opts}
         control the highlight:
-          - {higroup} highlight group for yanked region (default `"IncSearch"`)
+          - {higroup} highlight group for yanked region (default |hl-IncSearch|)
           - {timeout} time in ms before highlight is cleared (default `150`)
           - {on_macro} highlight when executing macro (default `false`)
           - {on_visual} highlight when yanking visual selection (default `true`)
-          - {event} event structure (default `vim.v.event`)
+          - {event} event structure (default |v:event|)
 
 vim.highlight.range({bufnr}, {ns}, {higroup}, {start}, {finish}, {rtype}, {inclusive})
                                                        *vim.highlight.range()*
@@ -1167,37 +1167,6 @@ region({bufnr}, {pos1}, {pos2}, {regtype}, {inclusive})         *vim.region()*
                 Return: ~
                     region lua table of the form {linenr = {startcol,endcol}}
 
-                                           *vim.register_keystroke_callback()*
-register_keystroke_callback({fn}, {ns_id})
-                Register a lua {fn} with an {id} to be run after every
-                keystroke.
-
-                If {fn} is nil, it removes the callback for the associated
-                {ns_id}
-                Note:
-                    {fn} will not be cleared from |nvim_buf_clear_namespace()|
-
-                Note:
-                    {fn} will receive the keystrokes after mappings have been
-                    evaluated
-
-                Parameters: ~
-                    {fn}     function: Function to call. It should take one
-                          argument, which is a string. The string will contain
-                          the literal keys typed. See |i_CTRL-V|
-                    {ns_id}  number? Namespace ID. If not passed or 0, will
-                             generate and return a new namespace ID from
-                             |nvim_create_namesapce()|
-
-                Return: ~
-                    number Namespace ID associated with {fn}
-
-                Note:
-                    {fn} will be automatically removed if an error occurs
-                    while calling. This is to prevent the annoying situation
-                    of every keystroke erroring while trying to remove a
-                    broken callback.
-
 schedule_wrap({cb})                                      *vim.schedule_wrap()*
                 Defers callback `cb` until the Nvim API is safe to call.
 
diff --git a/runtime/doc/starting.txt b/runtime/doc/starting.txt
index 5431ce3bd8..fe396a47ec 100644
--- a/runtime/doc/starting.txt
+++ b/runtime/doc/starting.txt
@@ -329,12 +329,12 @@ argument.
 -w{number}	Set the 'window' option to {number}.
 
 							*-w*
--w {scriptout}	All the characters that you type are recorded in the file
-		"scriptout", until you exit Vim.  This is useful if you want
-		to create a script file to be used with "vim -s" or
-		":source!".  When the "scriptout" file already exists, new
-		characters are appended.  See also |complex-repeat|.
-		{scriptout} cannot start with a digit.
+-w {scriptout}	All keys that you type are recorded in the file "scriptout",
+		until you exit Vim.  Useful to create a script file to be used
+		with "vim -s" or ":source!".  Appends to the "scriptout" file
+		if it already exists. {scriptout} cannot start with a digit.
+		See also |vim.on_key()|.
+		See also |complex-repeat|.
 
 							*-W*
 -W {scriptout}	Like -w, but do not append, overwrite an existing file.
diff --git a/runtime/doc/vim_diff.txt b/runtime/doc/vim_diff.txt
index 27c4b82aca..5bf9bc5a47 100644
--- a/runtime/doc/vim_diff.txt
+++ b/runtime/doc/vim_diff.txt
@@ -6,16 +6,16 @@
 
 Differences between Nvim and Vim			       *vim-differences*
 
-Nvim differs from Vim in many ways, although editor and VimL features are
-mostly identical.  This document is a complete and centralized reference of
-the differences.
+Nvim differs from Vim in many ways, although editor and Vimscript (not
+Vim9script) features are mostly identical.  This document is a complete and
+centralized reference of the differences.
 
 				      Type |gO| to see the table of contents.
 
 ==============================================================================
 1. Configuration					    *nvim-config*
 
-- Use `$XDG_CONFIG_HOME/nvim/init.vim` instead of `.vimrc` for configuration.
+- Use `$XDG_CONFIG_HOME/nvim/init.vim` instead of `.vimrc` for your |config|.
 - Use `$XDG_CONFIG_HOME/nvim` instead of `.vim` to store configuration files.
 - Use `$XDG_DATA_HOME/nvim/shada/main.shada` instead of `.viminfo` for persistent
   session information.  |shada|
@@ -78,17 +78,19 @@ the differences.
 MAJOR COMPONENTS ~
 
 API				|API|
-Lua scripting			|lua|
 Job control			|job-control|
-Remote plugins			|remote-plugin|
+LSP framework			|lsp|
+Lua scripting			|lua|
+Parsing engine			|treesitter|
 Providers
   Clipboard			|provider-clipboard|
   Node.js plugins		|provider-nodejs|
   Python plugins		|provider-python|
   Ruby plugins			|provider-ruby|
+Remote plugins			|remote-plugin|
 Shared data			|shada|
-Embedded terminal		|terminal|
-VimL parser			|nvim_parse_expression()|
+Terminal emulator		|terminal|
+Vimscript parser		|nvim_parse_expression()|
 XDG base directories		|xdg|
 
 USER EXPERIENCE  ~
@@ -137,7 +139,7 @@ FEATURES ~
 
 Command-line highlighting:
   The expression prompt (|@=|, |c_CTRL-R_=|, |i_CTRL-R_=|) is highlighted
-  using a built-in VimL expression parser. |expr-highlight|
+  using a built-in Vimscript expression parser. |expr-highlight|
 					*E5408* *E5409*
   |input()|, |inputdialog()| support custom highlighting. |input()-highlight|
 					*g:Nvim_color_cmdline*
@@ -380,7 +382,7 @@ TUI:
 UI/Display:
   |Visual| selection highlights the character at cursor. |visual-use|
 
-VimL (Vim script) compatibility:
+Vimscript compatibility:
   `count` does not alias to |v:count|
   `errmsg` does not alias to |v:errmsg|
   `shell_error` does not alias to |v:shell_error|
diff --git a/runtime/lua/vim/lsp/_snippet.lua b/runtime/lua/vim/lsp/_snippet.lua
new file mode 100644
index 0000000000..0140b0aee3
--- /dev/null
+++ b/runtime/lua/vim/lsp/_snippet.lua
@@ -0,0 +1,399 @@
+local P = {}
+
+---Take characters until the target characters (The escape sequence is '\' + char)
+---@param targets string[] The character list for stop consuming text.
+---@param specials string[] If the character isn't contained in targets/specials, '\' will be left.
+P.take_until = function(targets, specials)
+  targets = targets or {}
+  specials = specials or {}
+
+  return function(input, pos)
+    local new_pos = pos
+    local raw = {}
+    local esc = {}
+    while new_pos <= #input do
+      local c = string.sub(input, new_pos, new_pos)
+      if c == '\\' then
+        table.insert(raw, '\\')
+        new_pos = new_pos + 1
+        c = string.sub(input, new_pos, new_pos)
+        if not vim.tbl_contains(targets, c) and not vim.tbl_contains(specials, c) then
+          table.insert(esc, '\\')
+        end
+        table.insert(raw, c)
+        table.insert(esc, c)
+        new_pos = new_pos + 1
+      else
+        if vim.tbl_contains(targets, c) then
+          break
+        end
+        table.insert(raw, c)
+        table.insert(esc, c)
+        new_pos = new_pos + 1
+      end
+    end
+
+    if new_pos == pos then
+      return P.unmatch(pos)
+    end
+
+    return {
+      parsed = true,
+      value = {
+        raw = table.concat(raw, ''),
+        esc = table.concat(esc, '')
+      },
+      pos = new_pos,
+    }
+  end
+end
+
+P.unmatch = function(pos)
+  return {
+    parsed = false,
+    value = nil,
+    pos = pos,
+  }
+end
+
+P.map = function(parser, map)
+  return function(input, pos)
+    local result = parser(input, pos)
+    if result.parsed then
+      return {
+        parsed = true,
+        value = map(result.value),
+        pos = result.pos,
+      }
+    end
+    return P.unmatch(pos)
+  end
+end
+
+P.lazy = function(factory)
+  return function(input, pos)
+    return factory()(input, pos)
+  end
+end
+
+P.token = function(token)
+  return function(input, pos)
+    local maybe_token = string.sub(input, pos, pos + #token - 1)
+    if token == maybe_token then
+      return {
+        parsed = true,
+        value = maybe_token,
+        pos = pos + #token,
+      }
+    end
+    return P.unmatch(pos)
+  end
+end
+
+P.pattern = function(p)
+  return function(input, pos)
+    local maybe_match = string.match(string.sub(input, pos), '^' .. p)
+    if maybe_match then
+      return {
+        parsed = true,
+        value = maybe_match,
+        pos = pos + #maybe_match,
+      }
+    end
+    return P.unmatch(pos)
+  end
+end
+
+P.many = function(parser)
+  return function(input, pos)
+    local values = {}
+    local new_pos = pos
+    while new_pos <= #input do
+      local result = parser(input, new_pos)
+      if not result.parsed then
+        break
+      end
+      table.insert(values, result.value)
+      new_pos = result.pos
+    end
+    if #values > 0 then
+      return {
+        parsed = true,
+        value = values,
+        pos = new_pos,
+      }
+    end
+    return P.unmatch(pos)
+  end
+end
+
+P.any = function(...)
+  local parsers = { ... }
+  return function(input, pos)
+    for _, parser in ipairs(parsers) do
+      local result = parser(input, pos)
+      if result.parsed then
+        return result
+      end
+    end
+    return P.unmatch(pos)
+  end
+end
+
+P.opt = function(parser)
+  return function(input, pos)
+    local result = parser(input, pos)
+    return {
+      parsed = true,
+      value = result.value,
+      pos = result.pos,
+    }
+  end
+end
+
+P.seq = function(...)
+  local parsers = { ... }
+  return function(input, pos)
+    local values = {}
+    local new_pos = pos
+    for _, parser in ipairs(parsers) do
+      local result = parser(input, new_pos)
+      if result.parsed then
+        table.insert(values, result.value)
+        new_pos = result.pos
+      else
+        return P.unmatch(pos)
+      end
+    end
+    return {
+      parsed = true,
+      value = values,
+      pos = new_pos,
+    }
+  end
+end
+
+local Node = {}
+
+Node.Type = {
+  SNIPPET = 0,
+  TABSTOP = 1,
+  PLACEHOLDER = 2,
+  VARIABLE = 3,
+  CHOICE = 4,
+  TRANSFORM = 5,
+  FORMAT = 6,
+  TEXT = 7,
+}
+
+function Node:__tostring()
+  local insert_text = {}
+  if self.type == Node.Type.SNIPPET then
+    for _, c in ipairs(self.children) do
+      table.insert(insert_text, tostring(c))
+    end
+  elseif self.type == Node.Type.CHOICE then
+    table.insert(insert_text, self.items[1])
+  elseif self.type == Node.Type.PLACEHOLDER then
+    for _, c in ipairs(self.children or {}) do
+      table.insert(insert_text, tostring(c))
+    end
+  elseif self.type == Node.Type.TEXT then
+    table.insert(insert_text, self.esc)
+  end
+  return table.concat(insert_text, '')
+end
+
+--@see https://code.visualstudio.com/docs/editor/userdefinedsnippets#_grammar
+
+local S = {}
+S.dollar = P.token('$')
+S.open = P.token('{')
+S.close = P.token('}')
+S.colon = P.token(':')
+S.slash = P.token('/')
+S.comma = P.token(',')
+S.pipe = P.token('|')
+S.plus = P.token('+')
+S.minus = P.token('-')
+S.question = P.token('?')
+S.int = P.map(P.pattern('[0-9]+'), function(value)
+  return tonumber(value, 10)
+end)
+S.var = P.pattern('[%a_][%w_]+')
+S.text = function(targets, specials)
+  return P.map(P.take_until(targets, specials), function(value)
+    return setmetatable({
+      type = Node.Type.TEXT,
+      raw = value.raw,
+      esc = value.esc,
+    }, Node)
+  end)
+end
+
+S.toplevel = P.lazy(function()
+  return P.any(S.placeholder, S.tabstop, S.variable, S.choice)
+end)
+
+S.format = P.any(
+  P.map(P.seq(S.dollar, S.int), function(values)
+    return setmetatable({
+      type = Node.Type.FORMAT,
+      capture_index = values[2],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.int, S.close), function(values)
+    return setmetatable({
+      type = Node.Type.FORMAT,
+      capture_index = values[3],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.int, S.colon, S.slash, P.any(
+    P.token('upcase'),
+    P.token('downcase'),
+    P.token('capitalize'),
+    P.token('camelcase'),
+    P.token('pascalcase')
+  ), S.close), function(values)
+    return setmetatable({
+      type = Node.Type.FORMAT,
+      capture_index = values[3],
+      modifier = values[6],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.int, S.colon, P.any(
+    P.seq(S.question, P.take_until({ ':' }, { '\\' }), S.colon, P.take_until({ '}' }, { '\\' })),
+    P.seq(S.plus, P.take_until({ '}' }, { '\\' })),
+    P.seq(S.minus, P.take_until({ '}' }, { '\\' }))
+  ),  S.close), function(values)
+    return setmetatable({
+      type = Node.Type.FORMAT,
+      capture_index = values[3],
+      if_text = values[5][2].esc,
+      else_text = (values[5][4] or {}).esc,
+    }, Node)
+  end)
+)
+
+S.transform = P.map(P.seq(
+  S.slash,
+  P.take_until({ '/' }, { '\\' }),
+  S.slash,
+  P.many(P.any(S.format, S.text({ '$', '/' }, { '\\' }))),
+  S.slash,
+  P.opt(P.pattern('[ig]+'))
+), function(values)
+  return setmetatable({
+    type = Node.Type.TRANSFORM,
+    pattern = values[2].raw,
+    format = values[4],
+    option = values[6],
+  }, Node)
+end)
+
+S.tabstop = P.any(
+  P.map(P.seq(S.dollar, S.int), function(values)
+    return setmetatable({
+      type = Node.Type.TABSTOP,
+      tabstop = values[2],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.int, S.close), function(values)
+    return setmetatable({
+      type = Node.Type.TABSTOP,
+      tabstop = values[3],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.int, S.transform, S.close), function(values)
+    return setmetatable({
+      type = Node.Type.TABSTOP,
+      tabstop = values[3],
+      transform = values[4],
+    }, Node)
+  end)
+)
+
+S.placeholder = P.any(
+  P.map(P.seq(S.dollar, S.open, S.int, S.colon, P.many(P.any(S.toplevel, S.text({ '$', '}' }, { '\\' }))), S.close), function(values)
+    return setmetatable({
+      type = Node.Type.PLACEHOLDER,
+      tabstop = values[3],
+      children = values[5],
+    }, Node)
+  end)
+)
+
+S.choice = P.map(P.seq(
+  S.dollar,
+  S.open,
+  S.int,
+  S.pipe,
+  P.many(
+    P.map(P.seq(S.text({ ',', '|' }), P.opt(S.comma)), function(values)
+      return values[1].esc
+    end)
+  ),
+  S.pipe,
+  S.close
+), function(values)
+  return setmetatable({
+    type = Node.Type.CHOICE,
+    tabstop = values[3],
+    items = values[5],
+  }, Node)
+end)
+
+S.variable = P.any(
+  P.map(P.seq(S.dollar, S.var), function(values)
+    return setmetatable({
+      type = Node.Type.VARIABLE,
+      name = values[2],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.var, S.close), function(values)
+    return setmetatable({
+      type = Node.Type.VARIABLE,
+      name = values[3],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.var, S.transform, S.close), function(values)
+    return setmetatable({
+      type = Node.Type.VARIABLE,
+      name = values[3],
+      transform = values[4],
+    }, Node)
+  end),
+  P.map(P.seq(S.dollar, S.open, S.var, S.colon, P.many(P.any(S.toplevel, S.text({ '$', '}' }, { '\\' }))), S.close), function(values)
+    return setmetatable({
+      type = Node.Type.VARIABLE,
+      name = values[3],
+      children = values[5],
+    }, Node)
+  end)
+)
+
+S.snippet = P.map(P.many(P.any(S.toplevel, S.text({ '$' }, { '}', '\\' }))), function(values)
+  return setmetatable({
+    type = Node.Type.SNIPPET,
+    children = values,
+  }, Node)
+end)
+
+local M = {}
+
+---The snippet node type enum
+---@types table<string, number>
+M.NodeType = Node.Type
+
+---Parse snippet string and returns the AST
+---@param input string
+---@return table
+function M.parse(input)
+  local result = S.snippet(input, 1)
+  if not result.parsed then
+    error('snippet parsing failed.')
+  end
+  return result.value
+end
+
+return M
diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index 06afc2c5e2..18a2b60a7a 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -1,4 +1,5 @@
 local protocol = require 'vim.lsp.protocol'
+local snippet = require 'vim.lsp._snippet'
 local vim = vim
 local validate = vim.validate
 local api = vim.api
@@ -579,9 +580,13 @@ end
 --@param input (string) unparsed snippet
 --@returns (string) parsed snippet
 function M.parse_snippet(input)
-  local res, _ = parse_snippet_rec(input, false)
-
-  return res
+  local ok, parsed = pcall(function()
+    return tostring(snippet.parse(input))
+  end)
+  if not ok then
+    return input
+  end
+  return parsed
 end
 
 --@private
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index 5c2eed363e..1d43f22fa6 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -1555,8 +1555,8 @@ int vgetc(void)
    */
   may_garbage_collect = false;
 
-  // Exec lua callbacks for on_keystroke
-  nlua_execute_log_keystroke(c);
+  // Execute Lua on_key callbacks.
+  nlua_execute_on_key(c);
 
   return c;
 }
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 4d4286354b..855834aba4 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -1490,7 +1490,7 @@ int nlua_expand_pat(expand_T *xp,
   lua_getfield(lstate, -1, "_expand_pat");
   luaL_checktype(lstate, -1, LUA_TFUNCTION);
 
-  // [ vim, vim._log_keystroke, buf ]
+  // [ vim, vim._on_key, buf ]
   lua_pushlstring(lstate, (const char *)pat, STRLEN(pat));
 
   if (lua_pcall(lstate, 1, 2, 0) != 0) {
@@ -1764,7 +1764,7 @@ char_u *nlua_register_table_as_callable(typval_T *const arg)
   return name;
 }
 
-void nlua_execute_log_keystroke(int c)
+void nlua_execute_on_key(int c)
 {
   char_u buf[NUMBUFLEN];
   size_t buf_len = special_to_buf(c, mod_mask, false, buf);
@@ -1778,17 +1778,17 @@ void nlua_execute_log_keystroke(int c)
   // [ vim ]
   lua_getglobal(lstate, "vim");
 
-  // [ vim, vim._log_keystroke ]
-  lua_getfield(lstate, -1, "_log_keystroke");
+  // [ vim, vim._on_key]
+  lua_getfield(lstate, -1, "_on_key");
   luaL_checktype(lstate, -1, LUA_TFUNCTION);
 
-  // [ vim, vim._log_keystroke, buf ]
+  // [ vim, vim._on_key, buf ]
   lua_pushlstring(lstate, (const char *)buf, buf_len);
 
   if (lua_pcall(lstate, 1, 0, 0)) {
     nlua_error(
         lstate,
-        _("Error executing vim.log_keystroke lua callback: %.*s"));
+        _("Error executing  vim.on_key Lua callback: %.*s"));
   }
 
   // [ vim ]
diff --git a/src/nvim/lua/vim.lua b/src/nvim/lua/vim.lua
index 8cecaa51dd..e0118ab035 100644
--- a/src/nvim/lua/vim.lua
+++ b/src/nvim/lua/vim.lua
@@ -4,6 +4,7 @@
 --    1. runtime/lua/vim/ (the runtime): For "nice to have" features, e.g. the
 --       `inspect` and `lpeg` modules.
 --    2. runtime/lua/vim/shared.lua: Code shared between Nvim and tests.
+--       (This will go away if we migrate to nvim as the test-runner.)
 --    3. src/nvim/lua/: Compiled-into Nvim itself.
 --
 -- Guideline: "If in doubt, put it in the runtime".
@@ -425,26 +426,35 @@ function vim.notify(msg, log_level, _opts)
 end
 
 
-local on_keystroke_callbacks = {}
+function vim.register_keystroke_callback()
+  error('vim.register_keystroke_callback is deprecated, instead use: vim.on_key')
+end
+
+local on_key_cbs = {}
 
---- Register a lua {fn} with an {id} to be run after every keystroke.
+--- Adds Lua function {fn} with namespace id {ns_id} as a listener to every,
+--- yes every, input key.
 ---
---@param fn function: Function to call. It should take one argument, which is a string.
----                   The string will contain the literal keys typed.
----                   See |i_CTRL-V|
+--- The Nvim command-line option |-w| is related but does not support callbacks
+--- and cannot be toggled dynamically.
 ---
+---@param fn function: Callback function. It should take one string argument.
+---                   On each key press, Nvim passes the key char to fn(). |i_CTRL-V|
 ---                   If {fn} is nil, it removes the callback for the associated {ns_id}
---@param ns_id number? Namespace ID. If not passed or 0, will generate and return a new
----                    namespace ID from |nvim_create_namesapce()|
+---@param ns_id number? Namespace ID. If nil or 0, generates and returns a new
+---                    |nvim_create_namesapce()| id.
 ---
---@return number Namespace ID associated with {fn}
+---@return number Namespace id associated with {fn}. Or count of all callbacks
+---if on_key() is called without arguments.
 ---
---@note {fn} will be automatically removed if an error occurs while calling.
----     This is to prevent the annoying situation of every keystroke erroring
----     while trying to remove a broken callback.
---@note {fn} will not be cleared from |nvim_buf_clear_namespace()|
---@note {fn} will receive the keystrokes after mappings have been evaluated
-function vim.register_keystroke_callback(fn, ns_id)
+---@note {fn} will be removed if an error occurs while calling.
+---@note {fn} will not be cleared by |nvim_buf_clear_namespace()|
+---@note {fn} will receive the keys after mappings have been evaluated
+function vim.on_key(fn, ns_id)
+  if fn == nil and ns_id == nil then
+    return #on_key_cbs
+  end
+
   vim.validate {
     fn = { fn, 'c', true},
     ns_id = { ns_id, 'n', true }
@@ -454,20 +464,19 @@ function vim.register_keystroke_callback(fn, ns_id)
     ns_id = vim.api.nvim_create_namespace('')
   end
 
-  on_keystroke_callbacks[ns_id] = fn
+  on_key_cbs[ns_id] = fn
   return ns_id
 end
 
---- Function that executes the keystroke callbacks.
---@private
-function vim._log_keystroke(char)
+--- Executes the on_key callbacks.
+---@private
+function vim._on_key(char)
   local failed_ns_ids = {}
   local failed_messages = {}
-  for k, v in pairs(on_keystroke_callbacks) do
+  for k, v in pairs(on_key_cbs) do
     local ok, err_msg = pcall(v, char)
     if not ok then
-      vim.register_keystroke_callback(nil, k)
-
+      vim.on_key(nil, k)
       table.insert(failed_ns_ids, k)
       table.insert(failed_messages, err_msg)
     end
@@ -475,7 +484,7 @@ function vim._log_keystroke(char)
 
   if failed_ns_ids[1] then
     error(string.format(
-      "Error executing 'on_keystroke' with ns_ids of '%s'\n    With messages: %s",
+      "Error executing 'on_key' with ns_ids '%s'\n    Messages: %s",
       table.concat(failed_ns_ids, ", "),
       table.concat(failed_messages, "\n")))
   end
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 7d7eba2105..6738b93124 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -338,7 +338,7 @@ int main(int argc, char **argv)
     // prepare screen now, so external UIs can display messages
     starting = NO_BUFFERS;
     screenclear();
-    TIME_MSG("initialized screen early for UI");
+    TIME_MSG("init screen for UI");
   }
 
 
diff --git a/test/README.md b/test/README.md
index a6e9080a40..8669ab6f3e 100644
--- a/test/README.md
+++ b/test/README.md
@@ -258,6 +258,9 @@ Number; !must be defined to function properly):
 
 - `TEST_SKIP_FRAGILE` (F) (D): makes test suite skip some fragile tests.
 
+- `TEST_TIMEOUT` (FU) (I): specifies maximum time, in seconds, before the test
+  suite run is killed
+
 - `NVIM_PROG`, `NVIM_PRG` (F) (S): override path to Neovim executable (default
   to `build/bin/nvim`).
 
diff --git a/test/functional/api/server_notifications_spec.lua b/test/functional/api/server_notifications_spec.lua
index 9ee2570798..047bbfeb21 100644
--- a/test/functional/api/server_notifications_spec.lua
+++ b/test/functional/api/server_notifications_spec.lua
@@ -5,6 +5,7 @@ local eq, clear, eval, command, nvim, next_msg =
 local meths = helpers.meths
 local exec_lua = helpers.exec_lua
 local retry = helpers.retry
+local isCI = helpers.isCI
 
 describe('notify', function()
   local channel
@@ -76,6 +77,10 @@ describe('notify', function()
   end)
 
   it('cancels stale events on channel close', function()
+    if isCI() then
+      pending('hangs on CI #14083 #15251')
+      return
+    end
     if helpers.pending_win32(pending) then return end
     local catchan = eval("jobstart(['cat'], {'rpc': v:true})")
     eq({id=catchan, stream='job', mode='rpc', client = {}}, exec_lua ([[
diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 976e63b44d..c920a08faa 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -6,6 +6,7 @@ local funcs = helpers.funcs
 local meths = helpers.meths
 local dedent = helpers.dedent
 local command = helpers.command
+local insert = helpers.insert
 local clear = helpers.clear
 local eq = helpers.eq
 local ok = helpers.ok
@@ -1855,7 +1856,7 @@ describe('lua stdlib', function()
   end)
 
   it('vim.region', function()
-    helpers.insert(helpers.dedent( [[
+    insert(helpers.dedent( [[
     text tααt tααt text
     text tαxt txtα tex
     text tαxt tαxt
@@ -1863,65 +1864,67 @@ describe('lua stdlib', function()
     eq({5,15}, exec_lua[[ return vim.region(0,{1,5},{1,14},'v',true)[1] ]])
   end)
 
-  describe('vim.execute_on_keystroke', function()
-    it('should keep track of keystrokes', function()
-      helpers.insert([[hello world ]])
+  describe('vim.on_key', function()
+    it('tracks keystrokes', function()
+      insert([[hello world ]])
 
       exec_lua [[
-        KeysPressed = {}
+        keys = {}
 
-        vim.register_keystroke_callback(function(buf)
+        vim.on_key(function(buf)
           if buf:byte() == 27 then
             buf = "<ESC>"
           end
 
-          table.insert(KeysPressed, buf)
+          table.insert(keys, buf)
         end)
       ]]
 
-      helpers.insert([[next 🤦 lines å ]])
+      insert([[next 🤦 lines å ]])
 
       -- It has escape in the keys pressed
-      eq('inext 🤦 lines å <ESC>', exec_lua [[return table.concat(KeysPressed, '')]])
+      eq('inext 🤦 lines å <ESC>', exec_lua [[return table.concat(keys, '')]])
     end)
 
-    it('should allow removing trackers.', function()
-      helpers.insert([[hello world]])
+    it('allows removing on_key listeners', function()
+      insert([[hello world]])
 
       exec_lua [[
-        KeysPressed = {}
+        keys = {}
 
-        return vim.register_keystroke_callback(function(buf)
+        return vim.on_key(function(buf)
           if buf:byte() == 27 then
             buf = "<ESC>"
           end
 
-          table.insert(KeysPressed, buf)
+          table.insert(keys, buf)
         end, vim.api.nvim_create_namespace("logger"))
       ]]
 
-      helpers.insert([[next lines]])
+      insert([[next lines]])
 
-      exec_lua("vim.register_keystroke_callback(nil, vim.api.nvim_create_namespace('logger'))")
+      eq(1, exec_lua('return vim.on_key()'))
+      exec_lua("vim.on_key(nil, vim.api.nvim_create_namespace('logger'))")
+      eq(0, exec_lua('return vim.on_key()'))
 
-      helpers.insert([[more lines]])
+      insert([[more lines]])
 
       -- It has escape in the keys pressed
-      eq('inext lines<ESC>', exec_lua [[return table.concat(KeysPressed, '')]])
+      eq('inext lines<ESC>', exec_lua [[return table.concat(keys, '')]])
     end)
 
-    it('should not call functions that error again.', function()
-      helpers.insert([[hello world]])
+    it('skips any function that caused an error', function()
+      insert([[hello world]])
 
       exec_lua [[
-        KeysPressed = {}
+        keys = {}
 
-        return vim.register_keystroke_callback(function(buf)
+        return vim.on_key(function(buf)
           if buf:byte() == 27 then
             buf = "<ESC>"
           end
 
-          table.insert(KeysPressed, buf)
+          table.insert(keys, buf)
 
           if buf == 'l' then
             error("Dumb Error")
@@ -1929,35 +1932,30 @@ describe('lua stdlib', function()
         end)
       ]]
 
-      helpers.insert([[next lines]])
-      helpers.insert([[more lines]])
+      insert([[next lines]])
+      insert([[more lines]])
 
       -- Only the first letter gets added. After that we remove the callback
-      eq('inext l', exec_lua [[ return table.concat(KeysPressed, '') ]])
+      eq('inext l', exec_lua [[ return table.concat(keys, '') ]])
     end)
 
-    it('should process mapped keys, not unmapped keys', function()
+    it('processes mapped keys, not unmapped keys', function()
       exec_lua [[
-        KeysPressed = {}
+        keys = {}
 
         vim.cmd("inoremap hello world")
 
-        vim.register_keystroke_callback(function(buf)
+        vim.on_key(function(buf)
           if buf:byte() == 27 then
             buf = "<ESC>"
           end
 
-          table.insert(KeysPressed, buf)
+          table.insert(keys, buf)
         end)
       ]]
+      insert("hello")
 
-      helpers.insert("hello")
-
-      local next_status = exec_lua [[
-        return table.concat(KeysPressed, '')
-      ]]
-
-      eq("iworld<ESC>", next_status)
+      eq('iworld<ESC>', exec_lua[[return table.concat(keys, '')]])
     end)
   end)
 
diff --git a/test/functional/plugin/lsp/snippet_spec.lua b/test/functional/plugin/lsp/snippet_spec.lua
new file mode 100644
index 0000000000..4e127743eb
--- /dev/null
+++ b/test/functional/plugin/lsp/snippet_spec.lua
@@ -0,0 +1,152 @@
+local helpers = require('test.functional.helpers')(after_each)
+local snippet = require('vim.lsp._snippet')
+
+local eq = helpers.eq
+local exec_lua = helpers.exec_lua
+
+describe('vim.lsp._snippet', function()
+  before_each(helpers.clear)
+  after_each(helpers.clear)
+
+  local parse = function(...)
+    return exec_lua('return require("vim.lsp._snippet").parse(...)', ...)
+  end
+
+  it('should parse only text', function()
+    eq({
+      type = snippet.NodeType.SNIPPET,
+      children = {
+        {
+          type = snippet.NodeType.TEXT,
+          raw = 'TE\\$\\}XT',
+          esc = 'TE$}XT'
+        }
+      }
+    }, parse('TE\\$\\}XT'))
+  end)
+
+  it('should parse tabstop', function()
+    eq({
+      type = snippet.NodeType.SNIPPET,
+      children = {
+        {
+          type = snippet.NodeType.TABSTOP,
+          tabstop = 1,
+        },
+        {
+          type = snippet.NodeType.TABSTOP,
+          tabstop = 2,
+        }
+      }
+    }, parse('$1${2}'))
+  end)
+
+  it('should parse placeholders', function()
+    eq({
+      type = snippet.NodeType.SNIPPET,
+      children = {
+        {
+          type = snippet.NodeType.PLACEHOLDER,
+          tabstop = 1,
+          children = {
+            {
+              type = snippet.NodeType.PLACEHOLDER,
+              tabstop = 2,
+              children = {
+                {
+                  type = snippet.NodeType.TEXT,
+                  raw = 'TE\\$\\}XT',
+                  esc = 'TE$}XT'
+                },
+                {
+                  type = snippet.NodeType.TABSTOP,
+                  tabstop = 3,
+                },
+                {
+                  type = snippet.NodeType.TABSTOP,
+                  tabstop = 1,
+                  transform = {
+                    type = snippet.NodeType.TRANSFORM,
+                    pattern = 'regex',
+                    option = 'i',
+                    format = {
+                      {
+                        type = snippet.NodeType.FORMAT,
+                        capture_index = 1,
+                        modifier = 'upcase'
+                      }
+                    }
+                  },
+                },
+                {
+                  type = snippet.NodeType.TEXT,
+                  raw = 'TE\\$\\}XT',
+                  esc = 'TE$}XT'
+                },
+              }
+            }
+          }
+        },
+      }
+    }, parse('${1:${2:TE\\$\\}XT$3${1/regex/${1:/upcase}/i}TE\\$\\}XT}}'))
+  end)
+
+  it('should parse variables', function()
+    eq({
+      type = snippet.NodeType.SNIPPET,
+      children = {
+        {
+          type = snippet.NodeType.VARIABLE,
+          name = 'VAR',
+        },
+        {
+          type = snippet.NodeType.VARIABLE,
+          name = 'VAR',
+        },
+        {
+          type = snippet.NodeType.VARIABLE,
+          name = 'VAR',
+          children = {
+            {
+              type = snippet.NodeType.TABSTOP,
+              tabstop = 1,
+            }
+          }
+        },
+        {
+          type = snippet.NodeType.VARIABLE,
+          name = 'VAR',
+          transform = {
+            type = snippet.NodeType.TRANSFORM,
+            pattern = 'regex',
+            format = {
+              {
+                type = snippet.NodeType.FORMAT,
+                capture_index = 1,
+                modifier = 'upcase',
+              }
+            }
+          }
+        },
+      }
+    }, parse('$VAR${VAR}${VAR:$1}${VAR/regex/${1:/upcase}/}'))
+  end)
+
+  it('should parse choice', function()
+    eq({
+      type = snippet.NodeType.SNIPPET,
+      children = {
+        {
+          type = snippet.NodeType.CHOICE,
+          tabstop = 1,
+          items = {
+            ',',
+            '|'
+          }
+        }
+      }
+    }, parse('${1|\\,,\\||}'))
+  end)
+
+end)
+
diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index 508a9f2aed..d1a34e8d9b 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -1441,8 +1441,10 @@ describe('LSP', function()
         { label='foocar', sortText="h", insertText='foodar(${1:var1} typ1, ${2:var2} *typ2) {$0\\}', insertTextFormat=2, textEdit={} },
         -- nested snippet tokens
         { label='foocar', sortText="i", insertText='foodar(${1:var1 ${2|typ2,typ3|} ${3:tail}}) {$0\\}', insertTextFormat=2, textEdit={} },
+        -- braced tabstop
+        { label='foocar', sortText="j", insertText='foodar()${0}', insertTextFormat=2, textEdit={} },
         -- plain text
-        { label='foocar', sortText="j", insertText='foodar(${1:var1})', insertTextFormat=1, textEdit={} },
+        { label='foocar', sortText="k", insertText='foodar(${1:var1})', insertTextFormat=1, textEdit={} },
       }
       local completion_list_items = {items=completion_list}
       local expected = {
@@ -1454,8 +1456,9 @@ describe('LSP', function()
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foobar', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="f", textEdit={newText='foobar'} } } } } },
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foobar(place holder, more ...holder{})', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="g", insertText='foodar', insertTextFormat=2, textEdit={newText='foobar(${1:place holder}, ${2:more ...holder{\\}})'} } } } } },
         { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foodar(var1 typ1, var2 *typ2) {}', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="h", insertText='foodar(${1:var1} typ1, ${2:var2} *typ2) {$0\\}', insertTextFormat=2, textEdit={} } } } } },
-        { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foodar(var1 typ2,typ3 tail) {}', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="i", insertText='foodar(${1:var1 ${2|typ2,typ3|} ${3:tail}}) {$0\\}', insertTextFormat=2, textEdit={} } } } } },
-        { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foodar(${1:var1})', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="j", insertText='foodar(${1:var1})', insertTextFormat=1, textEdit={} } } } } },
+        { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foodar(var1 typ2 tail) {}', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="i", insertText='foodar(${1:var1 ${2|typ2,typ3|} ${3:tail}}) {$0\\}', insertTextFormat=2, textEdit={} } } } } },
+        { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foodar()', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="j", insertText='foodar()${0}', insertTextFormat=2, textEdit={} } } } } },
+        { abbr = 'foocar', dup = 1, empty = 1, icase = 1, info = ' ', kind = 'Unknown', menu = '', word = 'foodar(${1:var1})', user_data = { nvim = { lsp = { completion_item = { label='foocar', sortText="k", insertText='foodar(${1:var1})', insertTextFormat=1, textEdit={} } } } } },
       }
 
       eq(expected, exec_lua([[return vim.lsp.util.text_document_completion_list_to_complete_items(...)]], completion_list, prefix))