Remove schema migrations for v28 and earlier (#9031)

With LH v8.1.3 supporting Fulu-on-Gnosis, we no longer need these DB migrations. All Lighthouse nodes running in prod will soon be updated to LH v8.0.0+ and schema v28+.

This PR helps with Gloas fork choice changes, by allowing us to avoid updating old schema migrations when adding V29 for Gloas:

- https://github.com/sigp/lighthouse/pull/9025


  


Co-Authored-By: Michael Sproul <michael@sigmaprime.io>

consensus/fork_choice/src/fork_choice.rs

@@ -6,7 +6,6 @@ use proto_array::{
     Block as ProtoBlock, DisallowedReOrgOffsets, ExecutionStatus, JustifiedBalances,
     ProposerHeadError, ProposerHeadInfo, ProtoArrayForkChoice, ReOrgThreshold,
 };
-use ssz::{Decode, Encode};
 use ssz_derive::{Decode, Encode};
 use state_processing::{
     per_block_processing::errors::AttesterSlashingValidationError, per_epoch_processing,
@@ -1529,47 +1528,17 @@ where
 ///
 /// This is used when persisting the state of the fork choice to disk.
 #[superstruct(
-    variants(V17, V28),
+    variants(V28),
     variant_attributes(derive(Encode, Decode, Clone)),
     no_enum
 )]
 pub struct PersistedForkChoice {
-    #[superstruct(only(V17))]
-    pub proto_array_bytes: Vec<u8>,
-    #[superstruct(only(V28))]
     pub proto_array: proto_array::core::SszContainerV28,
     pub queued_attestations: Vec<QueuedAttestation>,
 }
 
 pub type PersistedForkChoice = PersistedForkChoiceV28;
 
-impl TryFrom<PersistedForkChoiceV17> for PersistedForkChoiceV28 {
-    type Error = ssz::DecodeError;
-
-    fn try_from(v17: PersistedForkChoiceV17) -> Result<Self, Self::Error> {
-        let container_v17 =
-            proto_array::core::SszContainerV17::from_ssz_bytes(&v17.proto_array_bytes)?;
-        let container_v28 = container_v17.into();
-
-        Ok(Self {
-            proto_array: container_v28,
-            queued_attestations: v17.queued_attestations,
-        })
-    }
-}
-
-impl From<(PersistedForkChoiceV28, JustifiedBalances)> for PersistedForkChoiceV17 {
-    fn from((v28, balances): (PersistedForkChoiceV28, JustifiedBalances)) -> Self {
-        let container_v17 = proto_array::core::SszContainerV17::from((v28.proto_array, balances));
-        let proto_array_bytes = container_v17.as_ssz_bytes();
-
-        Self {
-            proto_array_bytes,
-            queued_attestations: v28.queued_attestations,
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use types::MainnetEthSpec;

consensus/fork_choice/src/lib.rs

@@ -5,7 +5,7 @@ mod metrics;
 pub use crate::fork_choice::{
     AttestationFromBlock, Error, ForkChoice, ForkChoiceView, ForkchoiceUpdateParameters,
     InvalidAttestation, InvalidBlock, PayloadVerificationStatus, PersistedForkChoice,
-    PersistedForkChoiceV17, PersistedForkChoiceV28, QueuedAttestation, ResetPayloadStatuses,
+    PersistedForkChoiceV28, QueuedAttestation, ResetPayloadStatuses,
 };
 pub use fork_choice_store::ForkChoiceStore;
 pub use proto_array::{