Add HandleScope::new2 hack to construct from const ref (#290)

src/handle_scope.rs

@@ -45,6 +45,11 @@ impl<'s> HandleScope {
     let isolate: *mut Isolate = parent.isolate();
     Scope::new(isolate, parent)
   }
+
+  // TODO(ry) Remove this. This is a hack so we can upgrade Deno.
+  pub unsafe fn new2(isolate: &Isolate) -> Scope<'s, Self> {
+    Scope::new_root(isolate as *const _ as *mut Isolate)
+  }
 }
 
 unsafe impl<'s> ScopeDefinition<'s> for HandleScope {

tests/compile_fail/handle_scope_escape_to_nowhere.stderr

@@ -4,9 +4,9 @@ error[E0277]: the trait bound `rusty_v8::scope::Entered<'_, rusty_v8::scope::Cal
 7  |   let _hs = v8::EscapableHandleScope::new(cs.enter());
    |                                           ^^^^^^^^^^ the trait `rusty_v8::scope_traits::ToLocal<'_>` is not implemented for `rusty_v8::scope::Entered<'_, rusty_v8::scope::CallbackScope>`
    | 
-  ::: $WORKSPACE/src/handle_scope.rs:71:8
+  ::: $WORKSPACE/src/handle_scope.rs:76:8
    |
-71 |     P: ToLocalOrReturnsLocal<'p>,
+76 |     P: ToLocalOrReturnsLocal<'p>,
    |        ------------------------- required by this bound in `rusty_v8::handle_scope::EscapableHandleScope::new`
    |
    = help: the following implementations were found:

tests/test_api.rs

@@ -50,6 +50,18 @@ fn handle_scope_nested() {
   }
 }
 
+#[test]
+fn handle_scope_hack() {
+  let _setup_guard = setup();
+  let mut params = v8::Isolate::create_params();
+  params.set_array_buffer_allocator(v8::new_default_allocator());
+  let isolate = v8::Isolate::new(params);
+  let mut hs = unsafe { v8::HandleScope::new2(&isolate) };
+  let scope1 = hs.enter();
+  let l1 = v8::Integer::new(scope1, -123);
+  assert_eq!(v8::Integer::value(&l1), -123);
+}
+
 #[test]
 #[allow(clippy::float_cmp)]
 fn handle_scope_numbers() {