From 5393698ee6c5a455b4dad23c3b8c6c6ca0cb5f4a Mon Sep 17 00:00:00 2001
From: deelawn <dboltz03@gmail.com>
Date: Tue, 2 Jul 2024 18:30:55 +0100
Subject: [PATCH] fix(gnovm): Resolve RefValues before using as Objects (#2454)

Closes #2449.

I believe the bug was introduced by #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`.

<!-- please provide a detailed description of the changes made in this
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   |  2 +-
 gnovm/pkg/gnolang/values.go      |  4 +-
 gnovm/tests/files/issue-2449.gno | 65 ++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 4 deletions(-)
 create mode 100644 gnovm/tests/files/issue-2449.gno

diff --git a/gnovm/pkg/gnolang/ownership.go b/gnovm/pkg/gnolang/ownership.go
index 24d70b5dd84..16aeb905173 100644
--- a/gnovm/pkg/gnolang/ownership.go
+++ b/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:
diff --git a/gnovm/pkg/gnolang/values.go b/gnovm/pkg/gnolang/values.go
index d38c083428c..ef367f2c480 100644
--- a/gnovm/pkg/gnolang/values.go
+++ b/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.
diff --git a/gnovm/tests/files/issue-2449.gno b/gnovm/tests/files/issue-2449.gno
new file mode 100644
index 00000000000..6af4dbafc6c
--- /dev/null
+++ b/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