feat: Implement proposer component

Author: infrmtcs

builder/builder.go

@@ -137,6 +137,9 @@ func (b *Builder) PendingState(buildState *BuildState) (core.StateReader, func()
 }
 
 func (b *Builder) RunTxns(state *BuildState, txns []mempool.BroadcastedTransaction) error {
+	if len(txns) == 0 {
+		return nil
+	}
 	return b.executor.RunTxns(state, txns)
 }
 

builder/executor.go

@@ -43,6 +43,10 @@ func NewExecutor(
 // RunTxns executes the provided transaction and applies the state changes
 // to the pending state
 func (e *executor) RunTxns(state *BuildState, txns []mempool.BroadcastedTransaction) (err error) {
+	if len(txns) == 0 {
+		return nil
+	}
+
 	headState, headCloser, err := e.blockchain.HeadState()
 	if err != nil {
 		return err

builder/state.go

@@ -1,9 +1,13 @@
 package builder
 
 import (
+	"maps"
+	"slices"
+
 	"github.com/NethermindEth/juno/core"
 	"github.com/NethermindEth/juno/core/felt"
 	"github.com/NethermindEth/juno/sync"
+	"github.com/NethermindEth/juno/utils"
 )
 
 type BuildState struct {
@@ -26,3 +30,60 @@ func (b *BuildState) ClearPending() error {
 
 	return nil
 }
+
+// Assumptions we make to avoid deep copying some fields and types:
+// - This function is only called before running `Finish`
+// - *felt.Felt is immutable
+// - *GasPrice is immutable
+// - Signatures and EventsBloom are not set before `Finish` is called
+func (b *BuildState) Clone() BuildState {
+	return BuildState{
+		Pending:           clonePending(b.Pending),
+		RevealedBlockHash: b.RevealedBlockHash, // Safe to reuse an immutable value
+		L2GasConsumed:     b.L2GasConsumed,     // Value, safe to shallow copy
+	}
+}
+
+func clonePending(pending *sync.Pending) *sync.Pending {
+	return &sync.Pending{
+		Block:       cloneBlock(pending.Block),
+		StateUpdate: cloneStateUpdate(pending.StateUpdate),
+		NewClasses:  maps.Clone(pending.NewClasses),
+	}
+}
+
+func cloneBlock(block *core.Block) *core.Block {
+	return &core.Block{
+		Header:       utils.HeapPtr(*block.Header),
+		Transactions: slices.Clone(block.Transactions),
+		Receipts:     slices.Clone(block.Receipts),
+	}
+}
+
+func cloneStateUpdate(stateUpdate *core.StateUpdate) *core.StateUpdate {
+	return &core.StateUpdate{
+		BlockHash: stateUpdate.BlockHash,
+		NewRoot:   stateUpdate.NewRoot,
+		OldRoot:   stateUpdate.OldRoot,
+		StateDiff: cloneStateDiff(stateUpdate.StateDiff),
+	}
+}
+
+func cloneStateDiff(stateDiff *core.StateDiff) *core.StateDiff {
+	return &core.StateDiff{
+		StorageDiffs:      cloneStorageDiffs(stateDiff.StorageDiffs),
+		Nonces:            maps.Clone(stateDiff.Nonces),
+		DeployedContracts: maps.Clone(stateDiff.DeployedContracts),
+		DeclaredV0Classes: slices.Clone(stateDiff.DeclaredV0Classes),
+		DeclaredV1Classes: maps.Clone(stateDiff.DeclaredV1Classes),
+		ReplacedClasses:   maps.Clone(stateDiff.ReplacedClasses),
+	}
+}
+
+func cloneStorageDiffs(storageDiffs map[felt.Felt]map[felt.Felt]*felt.Felt) map[felt.Felt]map[felt.Felt]*felt.Felt {
+	result := make(map[felt.Felt]map[felt.Felt]*felt.Felt)
+	for key := range storageDiffs {
+		result[key] = maps.Clone(storageDiffs[key])
+	}
+	return result
+}

consensus/proposer/init_test.go

@@ -1,4 +1,4 @@
-package proposer
+package proposer_test
 
 import (
 	_ "github.com/NethermindEth/juno/encoder/registry"