tree-sitter-textobjects functionality limited in markdown embedded code fences #90

Checklist

• I have searched through the AstroNvim documentation
• I have searched through the existing issues of this project
• I have searched the existing issues of plugins related to this issue
• I can replicate the bug with the minimal repro.lua provided below

Neovim version (nvim -v)

0.12.5

Operating system/version

macOS Tahoe 26.7.1

Terminal/GUI

Ghostty

Describe the bug

Treesitter textobjects that target injected languages (e.g. if/af for @function.inner/@function.outer) are not available inside injected regions such as fenced code blocks in markdown.

astrocore.treesitter applies the default textobject mappings buffer-locally
and only when the buffer's top-level language has the capture in its
textobjects query:

Here lang is derived from the buffer's filetype (markdown), not the language
at the cursor:

Markdown's textobjects.scm in nvim-treesitter-textobjects only defines @class.* and @block.* captures, so if/af (and a?/i?, ao/io, aa/ia) are never mapped in markdown buffers.

However, nvim-treesitter-textobjects' select implementation already resolves injected trees: a plain global mapping to require("nvim-treesitter-textobjects.select").select_textobject("@function.inner", "textobjects") works correctly inside a lua/rust/python code fence in a markdown buffer. The per-buffer has_capture gate on the top-level language makes these textobjects unusable exactly where injection support would kick in.

Steps to Reproduce

1. Save the repro.lua below and create a test markdown file with some code fences in it like:

# heading

```lua
local function foo()
  return 1
end
```

2. nvim -u repro.lua test.md and wait for the markdown, markdown_inline, and lua parsers to install (may need a restart after first install).
3. Place the cursor on return 1 inside the code fence.
4. Press vif (or yif).
5. Nothing is selected because if is not mapped. :omap if reports "No mapping found", while :omap ik shows the buffer-local @block.inner mapping, confirming textobjects are active for the buffer.
6. For contrast, add a global mapping and repeat step 4; it selects the function body inside the fence:

vim.keymap.set({ "x", "o" }, "if", function()
  require("nvim-treesitter-textobjects.select").select_textobject("@function.inner", "textobjects")
end)

Expected behavior

vif/yif (and the other default textobjects) work inside injected language regions, like fenced code blocks in markdown, since the underlying plugin supports injections. For example, the has_capture check could consider the language of the injected tree at the cursor at mapping-invocation time (map the key, let the callback no-op when no capture matches), rather than deciding at buffer setup time based only on the top-level language.

Screenshots

No response

Additional Context

No response

Minimal configuration

-- save as repro.lua
-- run with nvim -u repro.lua
-- DO NOT change the paths
local root = vim.fn.fnamemodify("./.repro", ":p")

-- set stdpaths to use .repro
for _, name in ipairs({ "config", "data", "state", "runtime", "cache" }) do
  vim.env[("XDG_%s_HOME"):format(name:upper())] = root .. "/" .. name
end

-- bootstrap lazy
local lazypath = root .. "/plugins/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
  -- stylua: ignore
  vim.fn.system({ "git", "clone", "--filter=blob:none", "https://github.com/folke/lazy.nvim.git", "--branch=stable", lazypath })
end
vim.opt.rtp:prepend(vim.env.LAZY or lazypath)

-- install plugins
local plugins = {
  { "AstroNvim/AstroNvim", import = "astronvim.plugins" },
  { "AstroNvim/astrocommunity" },

  -- add any other plugins/customizations here
}
require("lazy").setup(plugins, {
  root = root .. "/plugins",
})

-- add anything else here (autocommands, vim.filetype, etc.)