Markdown parser issue in agent panel leading to Zed crash

[hardbyte]

Summary

Panic in markdown handling in agent panel

Description

Opening a particular thread which likely generated some malformed markdown immediately crashes zed. If running with --foreground this is displayed:

2025-05-11T19:32:27+12:00 ERROR [zed::reliability] {
  "thread": "<unnamed>",
  "payload": "begin <= end (3 <= 2) when slicing ```````",
  "location_data": {
    "file": "crates/markdown/src/parser.rs",
    "line": 82
  },
  "backtrace": [
    "zed::reliability::init_panic_hook::{{closure}}::h82b7729399e473b8+148938214",
    "std::panicking::rust_panic_with_hook::h541791bcc774ef34+121402131",
    "std::panicking::begin_panic_handler::{{closure}}::h6479a2f0137c7d19+121401354",
    "std::sys::backtrace::__rust_end_short_backtrace::ha04e7c0fc61ded91+121394873",
    "rust_begin_unwind+121400493",
    "core::panicking::panic_fmt::h5764ee7030b7a73d+8887824",
    "core::str::slice_error_fail_rt::h95fb5a3efddd85ad+41095820",
    "core::str::slice_error_fail::hbde71130ea7318aa+8889194",
    "markdown::parser::parse_markdown::h66530394140693c0+86860182",
    "markdown::Markdown::parse::{{closure}}::haf7a8805c18ee68d+86874933",
    "async_task::raw::RawTask<F,T,S,M>::run::h9c4a30249e869636+86675397",
    "std::sys::backtrace::__rust_begin_short_backtrace::hff786c63414b7612+67650579",
    "core::ops::function::FnOnce::call_once{{vtable.shim}}::hbd45c2658ca1da60+67769220",
    "std::sys::pal::unix::thread::Thread::new::thread_start::hcc5ed016d554f327+121432219",
    "start_thread+45007578503844",
    "clone3+45007579081788"
  ],
  "app_version": "0.186.6",
  "app_commit_sha": "c2d436d65576850a14acc68d9c919df6fe04058d",
  "release_channel": "preview",
  "target": "x86_64-unknown-linux-gnu",
  "os_name": "Linux X11",
  "os_version": "ubuntu 24.04",
  "architecture": "x86_64",
  "panicked_on": 1746948747321,
  "system_id": "9cc5507d-f770-4ead-9bdc-0a01b77a7a8b",
  "installation_id": "956ef9fc-3498-4034-ad31-5089bb84675f",
  "session_id": "2323e08b-6df6-43ed-a41f-4d0a5b62ace6"
}

Actual Behavior: Expected Behavior:

Zed Version and System Specs

Zed: v0.186.6 (Zed Preview) OS: Linux X11 ubuntu 24.04 Memory: 62.7 GiB Architecture: x86_64 GPU: NVIDIA GeForce RTX 3080 Ti || NVIDIA || 535.230.02

If applicable, attach your ~/Library/Logs/Zed/Zed.log file to this issue.

No response

[galoisgroupcn]

@hardbyte https://github.com/galoisgroupcn/zed/pull/4. Try this, and give us feedback if it works or not. If not, give us the output so that we can reiterate our code till it works. Thanks!

[hardbyte]

Wow, you all work quick! Thanks!