Fix VoteTracker decoding

consensus/proto_array/src/proto_array_fork_choice.rs

@@ -33,6 +33,45 @@ pub struct VoteTracker {
     next_payload_present: bool,
 }
 
+// Can be deleted once the V28 schema migration is buried.
+#[derive(Default, PartialEq, Clone, Encode, Decode)]
+pub struct VoteTrackerV28 {
+    current_root: Hash256,
+    next_root: Hash256,
+    current_slot: Slot,
+    next_slot: Slot,
+}
+
+// This impl is only used upon upgrade from pre-Gloas to Gloas with all pre-Gloas nodes.
+// The payload status is `false` for pre-Gloas nodes.
+impl From<VoteTrackerV28> for VoteTracker {
+    fn from(v: VoteTrackerV28) -> Self {
+        VoteTracker {
+            current_root: v.current_root,
+            next_root: v.next_root,
+            current_slot: v.current_slot,
+            next_slot: v.next_slot,
+            // TODO(gloas): check that this is correct
+            current_payload_present: false,
+            next_payload_present: false,
+        }
+    }
+}
+
+// This impl is only used upon downgrade from V29 to V28, with exclusively pre-Gloas nodes.
+impl From<VoteTracker> for VoteTrackerV28 {
+    fn from(v: VoteTracker) -> Self {
+        // Drop the payload_present, but this is safe because this is only called on pre-Gloas
+        // nodes.
+        VoteTrackerV28 {
+            current_root: v.current_root,
+            next_root: v.next_root,
+            current_slot: v.current_slot,
+            next_slot: v.next_slot,
+        }
+    }
+}
+
 pub struct LatestMessage {
     pub slot: Slot,
     pub root: Hash256,

consensus/proto_array/src/ssz_container.rs

@@ -2,7 +2,7 @@ use crate::proto_array::ProposerBoost;
 use crate::{
     Error, JustifiedBalances,
     proto_array::{ProtoArray, ProtoNode, ProtoNodeV17},
-    proto_array_fork_choice::{ElasticList, ProtoArrayForkChoice, VoteTracker},
+    proto_array_fork_choice::{ElasticList, ProtoArrayForkChoice, VoteTracker, VoteTrackerV28},
 };
 use ssz::{Encode, four_byte_option_impl};
 use ssz_derive::{Decode, Encode};
@@ -22,6 +22,9 @@ pub type SszContainer = SszContainerV29;
     no_enum
 )]
 pub struct SszContainer {
+    #[superstruct(only(V28))]
+    pub votes_v28: Vec<VoteTrackerV28>,
+    #[superstruct(only(V29))]
     pub votes: Vec<VoteTracker>,
     pub prune_threshold: usize,
     // Deprecated, remove in a future schema migration
@@ -75,7 +78,7 @@ impl TryFrom<(SszContainerV29, JustifiedBalances)> for ProtoArrayForkChoice {
 impl From<SszContainerV28> for SszContainerV29 {
     fn from(v28: SszContainerV28) -> Self {
         Self {
-            votes: v28.votes,
+            votes: v28.votes_v28.into_iter().map(Into::into).collect(),
             prune_threshold: v28.prune_threshold,
             nodes: v28
                 .nodes
@@ -98,7 +101,7 @@ impl From<SszContainerV28> for SszContainerV29 {
 impl From<SszContainerV29> for SszContainerV28 {
     fn from(v29: SszContainerV29) -> Self {
         Self {
-            votes: v29.votes,
+            votes_v28: v29.votes.into_iter().map(Into::into).collect(),
             prune_threshold: v29.prune_threshold,
             // These checkpoints are not consumed in v28 paths since the upgrade from v17,
             // we can safely default the values.