Migrate derivative to educe (#8125)

Fixes #7001.


  Mostly mechanical replacement of `derivative` attributes with `educe` ones.

### **Attribute Syntax Changes**

```rust
// Bounds: = "..." → (...)
#[derivative(Hash(bound = "E: EthSpec"))]
#[educe(Hash(bound(E: EthSpec)))]

// Ignore: = "ignore" → (ignore)
#[derivative(PartialEq = "ignore")]
#[educe(PartialEq(ignore))]

// Default values: value = "..." → expression = ...
#[derivative(Default(value = "ForkName::Base"))]
#[educe(Default(expression = ForkName::Base))]

// Methods: format_with/compare_with = "..." → method(...)
#[derivative(Debug(format_with = "fmt_peer_set_as_len"))]
#[educe(Debug(method(fmt_peer_set_as_len)))]

// Empty bounds: removed entirely, educe can infer appropriate bounds
#[derivative(Default(bound = ""))]
#[educe(Default)]

// Transparent debug: manual implementation (educe doesn't support it)
#[derivative(Debug = "transparent")]
// Replaced with manual Debug impl that delegates to inner field
```

**Note**: Some bounds use strings (`bound("E: EthSpec")`) for superstruct compatibility (`expected ','` errors).


Co-Authored-By: Javier Chávarri <javier.chavarri@gmail.com>

Co-Authored-By: Mac L <mjladson@pm.me>

Author: jchavarri

Cargo.lock

@@ -128,11 +128,11 @@ context_deserialize_derive = { path = "consensus/context_deserialize/context_des
 criterion = "0.5"
 delay_map = "0.4"
 deposit_contract = { path = "common/deposit_contract" }
-derivative = "2"
 directory = { path = "common/directory" }
 dirs = "3"
 discv5 = { version = "0.10", features = ["libp2p"] }
 doppelganger_service = { path = "validator_client/doppelganger_service" }
+educe = "0.6"
 eip_3076 = { path = "common/eip_3076" }
 either = "1.9"
 environment = { path = "lighthouse/environment" }

Cargo.toml

@@ -18,7 +18,7 @@ test_backfill = []
 alloy-primitives = { workspace = true }
 bitvec = { workspace = true }
 bls = { workspace = true }
-derivative = { workspace = true }
+educe = { workspace = true }
 eth2 = { workspace = true }
 eth2_network_config = { workspace = true }
 ethereum_hashing = { workspace = true }

beacon_node/beacon_chain/Cargo.toml

@@ -5,7 +5,7 @@
 //! reads when fork choice requires the validator balances of the justified state.
 
 use crate::{BeaconSnapshot, metrics};
-use derivative::Derivative;
+use educe::Educe;
 use fork_choice::ForkChoiceStore;
 use proto_array::JustifiedBalances;
 use safe_arith::ArithError;
@@ -127,10 +127,10 @@ impl BalancesCache {
 
 /// Implements `fork_choice::ForkChoiceStore` in order to provide a persistent backing to the
 /// `fork_choice::ForkChoice` struct.
-#[derive(Debug, Derivative)]
-#[derivative(PartialEq(bound = "E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>"))]
+#[derive(Debug, Educe)]
+#[educe(PartialEq(bound(E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>)))]
 pub struct BeaconForkChoiceStore<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> {
-    #[derivative(PartialEq = "ignore")]
+    #[educe(PartialEq(ignore))]
     store: Arc<HotColdDB<E, Hot, Cold>>,
     balances_cache: BalancesCache,
     time: Slot,

beacon_node/beacon_chain/src/beacon_fork_choice_store.rs

@@ -1,4 +1,4 @@
-use derivative::Derivative;
+use educe::Educe;
 use slot_clock::SlotClock;
 use std::marker::PhantomData;
 use std::sync::Arc;
@@ -245,8 +245,8 @@ impl<T: BeaconChainTypes, O: ObservationStrategy> GossipVerifiedBlob<T, O> {
 
 /// Wrapper over a `BlobSidecar` for which we have completed kzg verification.
 /// i.e. `verify_blob_kzg_proof(blob, commitment, proof) == true`.
-#[derive(Debug, Derivative, Clone, Encode, Decode)]
-#[derivative(PartialEq, Eq)]
+#[derive(Debug, Educe, Clone, Encode, Decode)]
+#[educe(PartialEq, Eq)]
 #[ssz(struct_behaviour = "transparent")]
 pub struct KzgVerifiedBlob<E: EthSpec> {
     blob: Arc<BlobSidecar<E>>,

beacon_node/beacon_chain/src/blob_verification.rs

@@ -66,7 +66,7 @@ use crate::{
     beacon_chain::{BeaconForkChoice, ForkChoiceError},
     metrics,
 };
-use derivative::Derivative;
+use educe::Educe;
 use eth2::types::{BlockGossip, EventKind};
 use execution_layer::PayloadStatus;
 pub use fork_choice::{AttestationFromBlock, PayloadVerificationStatus};
@@ -689,8 +689,8 @@ pub fn signature_verify_chain_segment<T: BeaconChainTypes>(
 
 /// A wrapper around a `SignedBeaconBlock` that indicates it has been approved for re-gossiping on
 /// the p2p network.
-#[derive(Derivative)]
-#[derivative(Debug(bound = "T: BeaconChainTypes"))]
+#[derive(Educe)]
+#[educe(Debug(bound(T: BeaconChainTypes)))]
 pub struct GossipVerifiedBlock<T: BeaconChainTypes> {
     pub block: Arc<SignedBeaconBlock<T::EthSpec>>,
     pub block_root: Hash256,

beacon_node/beacon_chain/src/block_verification.rs

@@ -2,7 +2,7 @@ use crate::data_availability_checker::AvailabilityCheckError;
 pub use crate::data_availability_checker::{AvailableBlock, MaybeAvailableBlock};
 use crate::data_column_verification::{CustodyDataColumn, CustodyDataColumnList};
 use crate::{PayloadVerificationOutcome, get_block_root};
-use derivative::Derivative;
+use educe::Educe;
 use ssz_types::VariableList;
 use state_processing::ConsensusContext;
 use std::fmt::{Debug, Formatter};
@@ -26,8 +26,8 @@ use types::{
 /// Note: We make a distinction over blocks received over gossip because
 /// in a post-deneb world, the blobs corresponding to a given block that are received
 /// over rpc do not contain the proposer signature for dos resistance.
-#[derive(Clone, Derivative)]
-#[derivative(Hash(bound = "E: EthSpec"))]
+#[derive(Clone, Educe)]
+#[educe(Hash(bound(E: EthSpec)))]
 pub struct RpcBlock<E: EthSpec> {
     block_root: Hash256,
     block: RpcBlockInner<E>,
@@ -80,8 +80,8 @@ impl<E: EthSpec> RpcBlock<E> {
 /// Note: This variant is intentionally private because we want to safely construct the
 /// internal variants after applying consistency checks to ensure that the block and blobs
 /// are consistent with respect to each other.
-#[derive(Debug, Clone, Derivative)]
-#[derivative(Hash(bound = "E: EthSpec"))]
+#[derive(Debug, Clone, Educe)]
+#[educe(Hash(bound(E: EthSpec)))]
 enum RpcBlockInner<E: EthSpec> {
     /// Single block lookup response. This should potentially hit the data availability cache.
     Block(Arc<SignedBeaconBlock<E>>),

beacon_node/beacon_chain/src/block_verification_types.rs

@@ -4,7 +4,7 @@ use crate::block_verification::{
 use crate::kzg_utils::{reconstruct_data_columns, validate_data_columns};
 use crate::observed_data_sidecars::{ObservationStrategy, Observe};
 use crate::{BeaconChain, BeaconChainError, BeaconChainTypes, metrics};
-use derivative::Derivative;
+use educe::Educe;
 use fork_choice::ProtoBlock;
 use kzg::{Error as KzgError, Kzg};
 use proto_array::Block;
@@ -296,8 +296,8 @@ impl<T: BeaconChainTypes, O: ObservationStrategy> GossipVerifiedDataColumn<T, O>
 }
 
 /// Wrapper over a `DataColumnSidecar` for which we have completed kzg verification.
-#[derive(Debug, Derivative, Clone, Encode, Decode)]
-#[derivative(PartialEq, Eq)]
+#[derive(Debug, Educe, Clone, Encode, Decode)]
+#[educe(PartialEq, Eq)]
 #[ssz(struct_behaviour = "transparent")]
 pub struct KzgVerifiedDataColumn<E: EthSpec> {
     data: Arc<DataColumnSidecar<E>>,
@@ -353,8 +353,8 @@ pub type CustodyDataColumnList<E> =
     VariableList<CustodyDataColumn<E>, <E as EthSpec>::NumberOfColumns>;
 
 /// Data column that we must custody
-#[derive(Debug, Derivative, Clone, Encode, Decode)]
-#[derivative(PartialEq, Eq, Hash(bound = "E: EthSpec"))]
+#[derive(Debug, Educe, Clone, Encode, Decode)]
+#[educe(PartialEq, Eq, Hash(bound(E: EthSpec)))]
 #[ssz(struct_behaviour = "transparent")]
 pub struct CustodyDataColumn<E: EthSpec> {
     data: Arc<DataColumnSidecar<E>>,
@@ -383,8 +383,8 @@ impl<E: EthSpec> CustodyDataColumn<E> {
 }
 
 /// Data column that we must custody and has completed kzg verification
-#[derive(Debug, Derivative, Clone, Encode, Decode)]
-#[derivative(PartialEq, Eq)]
+#[derive(Debug, Educe, Clone, Encode, Decode)]
+#[educe(PartialEq, Eq)]
 #[ssz(struct_behaviour = "transparent")]
 pub struct KzgVerifiedCustodyDataColumn<E: EthSpec> {
     data: Arc<DataColumnSidecar<E>>,

beacon_node/beacon_chain/src/data_column_verification.rs

@@ -1,5 +1,5 @@
 use crate::{BeaconChain, BeaconChainTypes};
-use derivative::Derivative;
+use educe::Educe;
 use slot_clock::SlotClock;
 use std::time::Duration;
 use strum::AsRefStr;
@@ -55,8 +55,8 @@ pub enum Error {
 }
 
 /// Wraps a `LightClientFinalityUpdate` that has been verified for propagation on the gossip network.
-#[derive(Derivative)]
-#[derivative(Clone(bound = "T: BeaconChainTypes"))]
+#[derive(Educe)]
+#[educe(Clone(bound(T: BeaconChainTypes)))]
 pub struct VerifiedLightClientFinalityUpdate<T: BeaconChainTypes> {
     light_client_finality_update: LightClientFinalityUpdate<T::EthSpec>,
     seen_timestamp: Duration,

beacon_node/beacon_chain/src/light_client_finality_update_verification.rs

@@ -1,5 +1,5 @@
 use crate::{BeaconChain, BeaconChainTypes};
-use derivative::Derivative;
+use educe::Educe;
 use eth2::types::Hash256;
 use slot_clock::SlotClock;
 use std::time::Duration;
@@ -49,8 +49,8 @@ pub enum Error {
 }
 
 /// Wraps a `LightClientOptimisticUpdate` that has been verified for propagation on the gossip network.
-#[derive(Derivative)]
-#[derivative(Clone(bound = "T: BeaconChainTypes"))]
+#[derive(Educe)]
+#[educe(Clone(bound(T: BeaconChainTypes)))]
 pub struct VerifiedLightClientOptimisticUpdate<T: BeaconChainTypes> {
     light_client_optimistic_update: LightClientOptimisticUpdate<T::EthSpec>,
     pub parent_root: Hash256,