Crash while debugging with chrome after rebuild of code

[rogerta]

Version: Deno 1.46.1

Crash while debugging with chrome after rebuild of code (see stack trace below)

Repro steps

1. Start deno app with command: deno serve --inspect --watch --allow-env --allow-read --allow-net --allow-ffi --unstable-ffi --port 9092 src/main.ts.
2. Use chrome 128.0.6613.119 (Official Build) (64-bit) as debugger. Click the Inspect link in the chrome://inspect/#devices page for the deno remote client to open a DevTools window.
3. Add a break point and step through the code. All works.
4. Make a change to the code so that the deno process restarts.
5. Close the chrome DevTools window and open a new one by clicking the Inspect link again.
6. Step through the code again.

Expected result
Debug app.

Actual result
deno crashes with the following stack trace:

Deno has panicked. This is a bug in Deno. Please report this
at https://github.com/denoland/deno/issues/new.
If you can reliably reproduce this panic, include the
reproduction steps and re-run with the RUST_BACKTRACE=1 env
var set and include the backtrace in your report.

Platform: linux x86_64
Version: 1.46.1
Args: ["deno", "serve", "--inspect", "--watch", "--allow-env", "--allow-read", "--allow-net", "--allow-ffi", "--unstable-ffi", "--port", "9092", "src/main.ts"]

thread 'main' panicked at /home/runner/.cargo/registry/src/index.crates.io-6f17d22bba15001f/deno_core-0.306.0/inspector.rs:367:16:
internal error: entered unreachable code
stack backtrace:
   0:     0x5d0e11983635 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hd736fd5964392270
   1:     0x5d0e119b5feb - core::fmt::write::hc6043626647b98ea
   2:     0x5d0e1197d69f - std::io::Write::write_fmt::h0d24b3e0473045db
   3:     0x5d0e1198340e - std::sys_common::backtrace::print::h45eb8174d25a1e76
   4:     0x5d0e11984e79 - std::panicking::default_hook::{{closure}}::haf3f0170eb4f3b53
   5:     0x5d0e11984c1a - std::panicking::default_hook::hb5d3b27aa9f6dcda
   6:     0x5d0e11f7578c - deno::setup_panic_hook::{{closure}}::hcc1c21dbb087ca94
   7:     0x5d0e119854eb - std::panicking::rust_panic_with_hook::h6b49d59f86ee588c
   8:     0x5d0e1198522b - std::panicking::begin_panic_handler::{{closure}}::hd4c2f7ed79b82b70
   9:     0x5d0e11983af9 - std::sys_common::backtrace::__rust_end_short_backtrace::h2946d6d32d7ea1ad
  10:     0x5d0e11984f97 - rust_begin_unwind
  11:     0x5d0e119b2f33 - core::panicking::panic_fmt::ha02418e5cd774672
  12:     0x5d0e119b2fdc - core::panicking::panic::h6c780fb115b2371d
  13:     0x5d0e13b065e5 - deno_core::inspector::JsRuntimeInspector::poll_sessions::h037919d508aeac48
  14:     0x5d0e13c2bbd6 - v8_inspector__V8InspectorClient__BASE__runMessageLoopOnPause
  15:     0x5d0e10f0b678 - _ZN12v8_inspector10V8Debugger18handleProgramBreakEN2v85LocalINS1_7ContextEEENS2_INS1_5ValueEEERKNSt4__Cr6vectorIiNS7_9allocatorIiEEEENS1_4base7EnumSetINS1_5debug11BreakReasonEiEENSG_13ExceptionTypeEb
  16:     0x5d0e10f0b9af - _ZN12v8_inspector10V8Debugger21BreakProgramRequestedEN2v85LocalINS1_7ContextEEERKNSt4__Cr6vectorIiNS5_9allocatorIiEEEENS1_4base7EnumSetINS1_5debug11BreakReasonEiEE
  17:     0x5d0e1044e645 - _ZN2v88internal5Debug12OnDebugBreakENS0_6HandleINS0_10FixedArrayEEENS0_10StepActionENS_4base7EnumSetINS_5debug11BreakReasonEiEE
  18:     0x5d0e1044da20 - _ZN2v88internal5Debug5BreakEPNS0_15JavaScriptFrameENS0_6HandleINS0_10JSFunctionEEE
  19:     0x5d0e10968224 - _ZN2v88internal28Runtime_DebugBreakOnBytecodeEiPmPNS0_7IsolateE
  20:     0x5d0e118232b6 - Builtins_CEntry_Return2_ArgvOnStack_NoBuiltinExit

The code that causes the crash is related to String and regex:

const matches = content.matchAll(/\${{.*?}}/g)  // `content` is a String
for (const m of [...matches].reverse()) {       // <--- crashes when stepping over this line

The command line args --allow-ffi --unstable-ffi are used here because the dependency jsr:@db/sqlite@0.12.0 requires it.

[littledivy]

I am not able to reproduce with your steps. Here's what I'm trying:

const content = "Hello, ${{.name}}!";

export default {
  fetch(req) {
    const matches = content.matchAll(/\${{.*?}}/g);
    for (const m of [...matches].reverse()) {
      console.log(m);
    }
    return new Response("Hello, world! x3");
  },
};

$ deno -V
v2.0.0-rc.4

$ deno serve --inspect --watch --port 1234 serve.ts
Watcher Process started.
Debugger listening on ws://127.0.0.1:9229/ws/031525d4-e40b-4d94-b5bb-5a66fa57c7a5
Visit chrome://inspect to connect to the debugger.
deno serve: Listening on http://0.0.0.0:1234/
[
  "${{.name}}",
  index: 7,
  input: "Hello, ${{.name}}!",
  groups: undefined
]
Debugger session started.
Watcher File change detected! Restarting!
Debugger listening on ws://127.0.0.1:9229/ws/a5deb91a-8cb8-4a40-a156-5fb3bc4d42af
Visit chrome://inspect to connect to the debugger.
deno serve: Listening on http://0.0.0.0:1234/
Debugger session started.
[
  "${{.name}}",
  index: 7,
  input: "Hello, ${{.name}}!",
  groups: undefined
]

Is it reliably reproducible or maybe something more specific in the code that triggers this?

[rogerta]

Sorry for late response. It is not very easily reproducible. It seem to reproduce more often when the source code changes and deno reloads the app due to the --watch argument.