Thread 'main' panicked at 'index out of bounds ...'

[SunJukebox]

Whenever I save a latex (.tex) file in neovim (stable, 0.7.2) with texlab running, the texlab instance crashes. The error message that it spits out when I set RUST_BACKTRACE=full is

[ERROR] .../vim/lsp/rpc.lua:420 "rpc" "texlab" "stderr" "thread 'main' panicked at 'index out of bounds: the len is 10 but the index is 10', src/line_index.rs:117:9\nstack backtrace:\n 0: 0x5570bf175944 - \n 1: 0x5570bf0459ec - \n 2: 0x5570bf171725 - \n 3: 0x5570bf1774ba - \n 4: 0x5570bf1771a9 - \n 5: 0x5570bf177b0a - \n 6: 0x5570bf1779e4 - \n 7: 0x5570bf175e74 - \n 8: 0x5570bf17774d - \n 9: 0x5570befb43e3 - \n 10: 0x5570befb4322 - \n 11: 0x5570bf214f81 - \n 12: 0x5570bf232ff7 - \n 13: 0x5570bf1ab8ab - \n 14: 0x5570bf2379f5 - \n 15: 0x5570bf0d81c0 - \n 16: 0x5570befcc7a3 - \n 17: 0x5570befd17dd - \n 18: 0x5570bf16a8ae - \n 19: 0x5570bf0d9062 - \n"
[ERROR] .../vim/lsp/rpc.lua:420 "rpc" "texlab" "stderr" " 20: 0x7f98b9b422d0 - \n 21: 0x7f98b9b4238a - __libc_start_main\n 22: 0x5570befcae05 - \n 23: 0x0 - \nthread '' panicked at 'called Result::unwrap() on an Err value: "SendError(..)"', /build/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/lsp-server-0.6.0/src/stdio.rs:29:37\nstack backtrace:\n "

For the sake of completeness, the source .tex file is

\documentclass{article}

\title{Test}

\begin{document}

\maketitle

\end{document}

However, when I run texlab -vvvv --log-file texlab.log instead of texlab, this error no longer appears; texlab runs without any hitches. I have no clue as to why this is the case. Thank you for any help you can offer.

[clason]

can you share your Neovim configuration for texlab?

[SunJukebox]

cmd = { "texlab" },
settings = {
  texlab = {
    build = { onSave = true },
      forwardSearch = {
        executable = "zathura",
        args = { "--synctex-forward", "%l:1:%f", "%p" },
      },
    },
  },
}

[clason]

and what's your texlab version?

[clason]

try specifying the full set of build arguments (see documentation)

[SunJukebox]

I am running version 4.2.1 . Thank you for the suggestion. I just tried with

build = {
          executable = 'latexmk',
          args = { '-pdf', '-interaction=nonstopmode', '-synctex=1', '%f' },
          onSave = false,
          forwardSearchAfter = false,
},

(keeping everything else the same), and I still received the same error.

[pfoerster]

Thanks for the report!

This problem is likely not caused by the build feature. Instead, texlab likely receives another textDocument/* request, which causes a lookup in the LineIndex so that the server can map line/column UTF-16 positions to UTF-8 offsets, which are used internally. Afterwards, the UTF-8 offsets are converted back to the LSP representation.

@SunJukebox
Does the example document include a final newline? The 10 in the panic message is the line number.

[SunJukebox]

Thanks for the detailed reply. There should be a final newline in the example that I did not add. Also, I want to add that, after downgrading texlab to v. 4.1.0, I no longer have this issue.

[pfoerster]

I think I have found the issue. Can you try out #730, please? The currently released version wrongly reloads the TeX file after saving, even if it still open in the editor. This can result in a text synchronization issue.

[SunJukebox]

Thank you @pfoerster for your help. Using texlab compiled from the issue-724 branch fixed the issue.