1 files changed, 54 insertions, 2 deletions
diff --git a/core/error.rs b/core/error.rs
index 16f813b89..07dc98a22 100644
--- a/core/error.rs
+++ b/core/error.rs
@@ -9,8 +9,7 @@ use std::fmt::Formatter;
 
 use anyhow::Error;
 
-use crate::realm::JsRealm;
-use crate::runtime::GetErrorClassFn;
+use crate::runtime::JsRealm;
 use crate::runtime::JsRuntime;
 use crate::source_map::apply_source_map;
 use crate::source_map::get_source_line;
@@ -20,6 +19,9 @@ use crate::url::Url;
 // TODO(ry) Deprecate AnyError and encourage deno_core::anyhow::Error instead.
 pub type AnyError = anyhow::Error;
 
+pub type JsErrorCreateFn = dyn Fn(JsError) -> Error;
+pub type GetErrorClassFn = &'static dyn for<'e> Fn(&'e Error) -> &'static str;
+
 /// Creates a new error with a caller-specified error class name and message.
 pub fn custom_error(
   class: &'static str,
@@ -643,6 +645,56 @@ fn abbrev_file_name(file_name: &str) -> Option<String> {
   Some(format!("{}:{},{}......{}", url.scheme(), head, start, end))
 }
 
+pub(crate) fn exception_to_err_result<T>(
+  scope: &mut v8::HandleScope,
+  exception: v8::Local<v8::Value>,
+  in_promise: bool,
+) -> Result<T, Error> {
+  let state_rc = JsRuntime::state_from(scope);
+
+  let was_terminating_execution = scope.is_execution_terminating();
+  // Disable running microtasks for a moment. When upgrading to V8 v11.4
+  // we discovered that canceling termination here will cause the queued
+  // microtasks to run which breaks some tests.
+  scope.set_microtasks_policy(v8::MicrotasksPolicy::Explicit);
+  // If TerminateExecution was called, cancel isolate termination so that the
+  // exception can be created. Note that `scope.is_execution_terminating()` may
+  // have returned false if TerminateExecution was indeed called but there was
+  // no JS to execute after the call.
+  scope.cancel_terminate_execution();
+  let mut exception = exception;
+  {
+    // If termination is the result of a `op_dispatch_exception` call, we want
+    // to use the exception that was passed to it rather than the exception that
+    // was passed to this function.
+    let state = state_rc.borrow();
+    exception = if let Some(exception) = &state.dispatched_exception {
+      v8::Local::new(scope, exception.clone())
+    } else if was_terminating_execution && exception.is_null_or_undefined() {
+      let message = v8::String::new(scope, "execution terminated").unwrap();
+      v8::Exception::error(scope, message)
+    } else {
+      exception
+    };
+  }
+
+  let mut js_error = JsError::from_v8_exception(scope, exception);
+  if in_promise {
+    js_error.exception_message = format!(
+      "Uncaught (in promise) {}",
+      js_error.exception_message.trim_start_matches("Uncaught ")
+    );
+  }
+
+  if was_terminating_execution {
+    // Resume exception termination.
+    scope.terminate_execution();
+  }
+  scope.set_microtasks_policy(v8::MicrotasksPolicy::Auto);
+
+  Err(js_error.into())
+}
+
 #[cfg(test)]
 mod tests {
   use super::*;