Crash when adding extmark in decor provider

[NobleMathews]

Problem

Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib                 0x183932a60 __pthread_kill + 8
1   libsystem_pthread.dylib                0x18396ac20 pthread_kill + 288
2   libsystem_c.dylib                      0x183877a20 abort + 180
3   libsystem_c.dylib                      0x183876d10 __assert_rtn + 284
4   nvim                                   0x104a83474 marktree_itr_next_skip.cold.1 + 40 (marktree.c:1558)
5   nvim                                   0x10485eac8 marktree_itr_next_skip + 584 (marktree.c:1558)
6   nvim                                   0x10475fe8c decor_redraw_col + 180 (decoration.c:614)
7   nvim                                   0x10476b87c win_line + 9020 (drawline.c:1667)
8   nvim                                   0x104772ecc win_update + 4924 (drawscreen.c:2302)
9   nvim                                   0x104771808 update_screen + 3256 (drawscreen.c:648)
10  nvim                                   0x10489c040 normal_redraw + 44 (normal.c:1354) [inlined]
11  nvim                                   0x10489c040 normal_check + 968 (normal.c:1456)
12  nvim                                   0x10493f474 state_enter + 100 (state.c:40)
13  nvim                                   0x10488f420 normal_enter + 160 (normal.c:519)
14  nvim                                   0x10484d8ac main + 9484 (main.c:664)
15  dyld                                   0x1835e20e0 start + 2360

Assert is firing:

      assert(itr->x->ptr[itr->i]->parent == itr->x);

Steps to reproduce

min.lua:

vim.wo.foldexpr = 'v:lua.vim.treesitter.foldexpr()'
vim.wo.foldmethod = 'expr'
vim.o.swapfile = false

vim.api.nvim_create_autocmd('FileType', {
  pattern = { 'c' },
  callback = function(args)
    vim.treesitter.start(args.buf)
    vim.lsp.start({
      cmd = { 'clangd' },
      root_dir = vim.fs.root(args.buf, {'.git'})
    })
  end,
})

local ns = vim.api.nvim_create_namespace('foldsize')
vim.api.nvim_set_decoration_provider(ns, {
  on_line = function(_, _winid, bufnr, row)
    vim.api.nvim_buf_clear_namespace(bufnr, ns, row, row+1)
    vim.api.nvim_buf_set_extmark(bufnr, ns, row, 0, {
      virt_text_pos = 'right_align',
      virt_text = { { 'TEXT', 'Folded' } },
    })
  end
})

1. Checkout nvim codebase
2. Install clangd
3. nvim --clean -u min.lua src/nvim/move.c
4. make window width ~20 cells
5. Gx

If that doesn't work, scroll, edit, close open folds. Eventually assert will trigger.

Neovim version (nvim -v)

NVIM v0.11.0-dev-312

Operating system/version

macOS 14.4.1

Terminal name/version

ghostty

$TERM environment variable

xterm-ghostty

Installation

Source

[mayil-ai[bot]]

Here are some code snippets that may help you get started:

• src/nvim/extmark.c:55-688 | The extmark_set function is central to the issue, as it involves updating and deleting extmarks, which is directly related to the crash. Reviewing this can ensure correct parent relationships in MarkTree.

To address the issue with the extmark crash, follow these actionable steps:

• Update extmark_set Function:

  • Ensure that when an extmark is revised or deleted, the MarkTree is updated to maintain correct parent relationships.
  • Review the logic for updating extmarks to confirm that all parent-child relationships are preserved.

• Modify marktree_put and marktree_del_itr:

  • Add checks or adjustments to ensure that parent pointers are correctly set and validated during insertion and deletion.
  • Verify that these functions maintain the integrity of the MarkTree structure.

• Enhance marktree_itr_next_skip:

  • Implement additional validation or logging to catch and diagnose parent relationship issues early.
  • Consider adding assertions or debug logs to track the state of parent pointers during iteration.

By implementing these steps, you can address the inconsistency in the MarkTree structure and prevent the assertion failure.

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