examples(core): panik (#15983)

core/examples/panik.rs

@@ -0,0 +1,35 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+//!  This example shows that op-panics currently result in UB (likely "failed to initiate panic")
+//!  without a custom panic hook that aborts the process or -C panic=abort.
+//!
+//!  This happens due to the UB of panicking in an extern "C",
+//!  given how ops are reduced via rusty_v8::MapFnTo
+//!  See:
+//!    - https://github.com/rust-lang/rust/issues/74990
+//!    - https://rust-lang.github.io/rfcs/2945-c-unwind-abi.html
+
+use deno_core::op;
+use deno_core::Extension;
+use deno_core::JsRuntime;
+use deno_core::RuntimeOptions;
+
+// This is a hack to make the `#[op]` macro work with
+// deno_core examples.
+// You can remove this:
+use deno_core::*;
+
+fn main() {
+  #[op]
+  fn op_panik() {
+    panic!("panik !!!")
+  }
+
+  let extensions =
+    vec![Extension::builder().ops(vec![op_panik::decl()]).build()];
+  let mut rt = JsRuntime::new(RuntimeOptions {
+    extensions,
+    ..Default::default()
+  });
+  rt.execute_script("panik", "Deno.core.ops.op_panik()")
+    .unwrap();
+}