From 111c7f434e2edf89c472119ac3ca4db3e6d80bd4 Mon Sep 17 00:00:00 2001
From: altermo <107814000+altermo@users.noreply.github.com>
Date: Thu, 16 Apr 2026 19:52:20 +0200
Subject: [PATCH] fix(treesitter): TSNode:id() with NUL byte causes unreliable
 select()  #39134

Problem:
`TSNode:id()` returns the underlying c pointer as a string, which may include
NUL bytes. In PUC Lua, `('%s'):format('\0a\0')` returns `''` and not `'\0a\0'`
(i.e. treats the string as a c-string (which terminates at the NUL byte)).

This resulted in two different nodes being able to have the same id.

Solution:
Use concatenation `..` instead of `string.format()`.

(cherry picked from commit bb2284d75e7e2b0587610d1ae4d681d185622645)
---
 runtime/lua/vim/treesitter/_select.lua     | 2 +-
 test/functional/treesitter/select_spec.lua | 4 ----
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/runtime/lua/vim/treesitter/_select.lua b/runtime/lua/vim/treesitter/_select.lua
index 5ff8e2d3c7..ffca1a1ce5 100644
--- a/runtime/lua/vim/treesitter/_select.lua
+++ b/runtime/lua/vim/treesitter/_select.lua
@@ -36,7 +36,7 @@ local M = {}
 --- @param node vim.treesitter.select.node
 --- @return string
 local function node_id(node)
-  return ('%s:%s'):format(table.concat({ unpack(node.top.region) }, ':'), node.node:id())
+  return table.concat({ unpack(node.top.region) }, ':') .. ':' .. node.node:id()
 end
 
 --- @param node vim.treesitter.select.node
diff --git a/test/functional/treesitter/select_spec.lua b/test/functional/treesitter/select_spec.lua
index 92d7d305bf..7f7df9a464 100644
--- a/test/functional/treesitter/select_spec.lua
+++ b/test/functional/treesitter/select_spec.lua
@@ -81,10 +81,6 @@ describe('treesitter incremental-selection', function()
     treeselect('select_next', 3)
     eq('4', get_selected())
 
-    if t.skip(jit == nil, 'sometimes fails on PUC lua') then
-      return
-    end
-
     treeselect('select_prev', 2)
     eq('2', get_selected())