Is it possible to catch a heap limit reached exception?

[thomas9911]

I have my code:

use std::path::Path;

use deno_runtime::deno_core::error::AnyError;
use deno_runtime::deno_core::v8;
use deno_runtime::deno_core::ModuleSpecifier;
use deno_runtime::permissions::PermissionsContainer;
use deno_runtime::worker::MainWorker;
use deno_runtime::worker::WorkerOptions;

#[tokio::main]
async fn main() -> Result<(), AnyError> {
    let js_path = Path::new(env!("CARGO_MANIFEST_DIR")).join("tmp.js");
    let main_module = ModuleSpecifier::from_file_path(js_path).unwrap();

    let mut create_params = v8::CreateParams::default();
    create_params = create_params.heap_limits(1024, 1 * 1024 * 1024);

    let mut worker = MainWorker::bootstrap_from_options(
        main_module.clone(),
        PermissionsContainer::allow_all(),
        WorkerOptions {
            create_params: Some(create_params),
            ..Default::default()
        },
    );
    worker.execute_main_module(&main_module).await?;
    worker.run_event_loop(false).await?;
    Ok(())
}

// tmp.js

let data = []

for (let i = 0; i < 1000000; i++) {
  data.push(i)
}

console.log(data)

the error:

<--- Last few GCs --->

[122021:0x558afdec36f0]        6 ms: Mark-Compact 1.0 (3.1) -> 0.6 (3.4) MB, 0.92 / 0.00 ms  (average mu = 0.682, current mu = 0.656) allocation failure; GC in old space requested


<--- JS stacktrace --->


#
# Fatal JavaScript out of memory: Reached heap limit
#

Trace/breakpoint trap (core dumped)

I tried to capture this using std::panic::catch_unwind but i assumed correctly that this doesn't work because it probably throws this panic/exception in the v8 c++ core somewhere.

Does anyone know if this is correct? and if it is even possible to capture this exception and handle it nicely?

[bartlomieju]

You're probably looking for https://docs.rs/deno_core/latest/deno_core/struct.JsRuntime.html#method.add_near_heap_limit_callback