🐞 Bug: Index out of bounds from vim.treesitter.get_node_text in parsers/markdown.lua on nvim 0.12.2

[antonich-blip]

Environment

• Neovim: 0.12.2
• markview.nvim: v28.1.0 (latest tag, same code on main)
• OS: Linux (NixOS)

Problem

When markview's async render fires on a recently-edited markdown buffer, the iterated
tree-sitter capture node's range occasionally extends past the current buffer end. On nvim
0.12, nvim_buf_get_text performs strict bounds checking and throws Index out of bounds
instead of returning silently as it did on 0.11.

Traceback

vim.schedule callback: .../treesitter.lua:212: Index out of bounds
stack traceback:
[C]: in function 'nvim_buf_get_text'
.../runtime/lua/vim/treesitter.lua:212: in function 'get_node_text'
.../markview.nvim/lua/markview/parsers/markdown.lua:977: in function 'parse'
.../markview.nvim/lua/markview/parser.lua:193: in function 'fn'
.../runtime/lua/vim/treesitter/languagetree.lua:717: in function 'for_each_tree'
.../markview.nvim/lua/markview/parser.lua:183: in function 'parse'
.../markview.nvim/lua/markview/actions.lua:189: in function 'render'
.../markview.nvim/lua/markview/autocmds.lua:327: in function ''
vim/_core/editor.lua: in function <vim/_core/editor.lua:0>

Offending code

lua/markview/parsers/markdown.lua:977 (also present on main):

local capture_text = vim.treesitter.get_node_text(capture_node, buffer);
local r_start, c_start, r_end, c_end = capture_node:range();

Suggested fix

Wrap in pcall, or validate the node range against the current buffer size before the call:
local ok, capture_text = pcall(vim.treesitter.get_node_text, capture_node, buffer)
if not ok or capture_text == nil then
    goto continue
end
This preserves the existing capture_text == nil guard path.

Reproduction

Happens intermittently when editing a markdown buffer quickly (typing, deleting paragraphs)
 with markview attached. The render is scheduled via vim.schedule (autocmds.lua:327), and
by the time it runs the TSTree parser has been invalidated relative to the buffer.

[OXY2DEV]

My markdown.lua#977 doesn't seem to match your one.

Can you switch to the main branch to see if it's fixed? @antonich-blip

---

When markview's async render fires on a recently-edited markdown buffer

There is no async happening btw. Neovim is single threaded.

On nvim
0.12, nvim_buf_get_text performs strict bounds checking and throws Index out of bounds
instead of returning silently as it did on 0.11.

This would be an issue of the tree-sitter-markdown parser and of Neovim's tree-sitter implementation as they are called internally.

[OXY2DEV]

Can you provide the reproduction steps? @antonich-blip

The text file will do(you can narrow it down to the line by deleting 1 line at a time untill the error goes away, the last deleted line would most likely have the issue).