fix(gnovm): Resolve RefValues before using as Objects (gnolang#2454)

Closes gnolang#2449.

I believe the bug was introduced by gnolang#2255. Previously, if the type of
`tv.V` in `GetFirstObject` was a `PointerValue`, it the `Base` would
have been nil in the scenario producing this bug. Now that `Base` can
never be nil for a `PointerValue`, the nil base check has been removed.
We do however need to account for a new scenario where the `Base` is a
`RefValue`, a type that does implement the `Object` interface. In the
case where the base is a `RefValue`, first resolve it by calling
`store.GetObject`.

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pull request. -->

<details><summary>Contributors' checklist...</summary>

- [x] Added new tests, or not needed, or not feasible
- [x] Provided an example (e.g. screenshot) to aid review or the PR is
self-explanatory
- [x] Updated the official documentation or not needed
- [x] No breaking changes were made, or a `BREAKING CHANGE: xxx` message
was included in the description
- [x] Added references to related issues and PRs
- [x] Provided any useful hints for running manual tests
- [x] Added new benchmarks to [generated
graphs](https://gnoland.github.io/benchmarks), if any. More info
[here](https://github.com/gnolang/gno/blob/master/.benchmarks/README.md).
</details>

gnovm/pkg/gnolang/ownership.go

@@ -333,7 +333,7 @@ func (tv *TypedValue) GetFirstObject(store Store) Object {
  // something in it; in that case, ignore the base. That will
  // likely require maybe a preparation step in persistence
  // ( or unlikely, a second type of ref-counting).
- return cv.Base.(Object)
+ return cv.GetBase(store)
  case *ArrayValue:
  return cv
  case *SliceValue:

gnovm/pkg/gnolang/values.go

@@ -192,7 +192,6 @@ const (
  PointerIndexNative = -3 // Base is *NativeValue.
 )
 
-/*
 func (pv *PointerValue) GetBase(store Store) Object {
  switch cbase := pv.Base.(type) {
  case nil:
@@ -204,10 +203,9 @@ func (pv *PointerValue) GetBase(store Store) Object {
  case Object:
  return cbase
  default:
- panic("should not happen")
+ panic(fmt.Sprintf("unexpected pointer base type %T", cbase))
  }
 }
-*/
 
 // cu: convert untyped; pass false for const definitions
 // TODO: document as something that enables into-native assignment.

gnovm/tests/files/issue-2449.gno

@@ -0,0 +1,65 @@
+// PKGPATH: gno.land/r/evt_test
+package evt_test
+
+type Event struct {
+ name string
+}
+
+var deletionEvents = []*Event{
+ {name: "event1"},
+ {name: "event2"},
+ {name: "event3"},
+ {name: "event4"},
+}
+
+var insertEvents = []*Event{
+ {name: "event1"},
+ {name: "event2"},
+}
+
+var appendEvents = []*Event{
+ {name: "event1"},
+}
+
+func DelEvent(name string) {
+ for i, event := range deletionEvents {
+ if event.name == name {
+ deletionEvents = append(deletionEvents[:i], deletionEvents[i+1:]...)
+ return
+ }
+ }
+}
+
+func InsertEvent(name string) {
+ insertEvents = append(insertEvents[:1], append([]*Event{{name: name}}, insertEvents[1:]...)...)
+}
+
+func AppendEvent(name string) {
+ appendEvents = append(appendEvents, &Event{name: name})
+}
+
+func printEvents(events []*Event) {
+ for _, event := range events {
+ println(event.name)
+ }
+}
+
+func main() {
+ DelEvent("event2")
+ InsertEvent("event1.5")
+ AppendEvent("event2")
+
+ printEvents(deletionEvents)
+ printEvents(insertEvents)
+ printEvents(appendEvents)
+}
+
+// Output:
+// event1
+// event3
+// event4
+// event1
+// event1.5
+// event2
+// event1
+// event2