From fbae35cd77cbbf8469fda2d19528cac166b915fe Mon Sep 17 00:00:00 2001
From: rian <rian.hughes@physics.ox.ac.uk>
Date: Tue, 14 Jan 2025 13:43:25 +0200
Subject: [PATCH] comments: merge method, const string

---
 core/state_update.go | 45 ++++++++++++++++++--------------------------
 genesis/genesis.go   | 12 +++++++++---
 2 files changed, 27 insertions(+), 30 deletions(-)

diff --git a/core/state_update.go b/core/state_update.go
index 41c344a9b..fd8deaf84 100644
--- a/core/state_update.go
+++ b/core/state_update.go
@@ -39,6 +39,24 @@ func (d *StateDiff) Length() uint64 {
 	return uint64(length)
 }
 
+func (d *StateDiff) Merge(incoming *StateDiff) {
+	mergeStorageDiffs := func(oldMap, newMap map[felt.Felt]map[felt.Felt]*felt.Felt) {
+		for addr, newAddrStorage := range newMap {
+			if oldAddrStorage, exists := oldMap[addr]; exists {
+				maps.Copy(oldAddrStorage, newAddrStorage)
+			} else {
+				oldMap[addr] = newAddrStorage
+			}
+		}
+	}
+	maps.Copy(d.Nonces, incoming.Nonces)
+	maps.Copy(d.DeployedContracts, incoming.DeployedContracts)
+	maps.Copy(d.DeclaredV1Classes, incoming.DeclaredV1Classes)
+	maps.Copy(d.ReplacedClasses, incoming.ReplacedClasses)
+	mergeStorageDiffs(d.StorageDiffs, incoming.StorageDiffs)
+	d.DeclaredV0Classes = append(d.DeclaredV0Classes, incoming.DeclaredV0Classes...)
+}
+
 var starknetStateDiff0 = new(felt.Felt).SetBytes([]byte("STARKNET_STATE_DIFF0"))
 
 func (d *StateDiff) Hash() *felt.Felt {
@@ -210,30 +228,3 @@ func EmptyStateDiff() *StateDiff {
 		ReplacedClasses:   make(map[felt.Felt]*felt.Felt),
 	}
 }
-
-func MergeStateDiffs(oldStateDiff, newStateDiff *StateDiff) *StateDiff {
-	mergeMaps := func(oldMap, newMap map[felt.Felt]*felt.Felt) {
-		for key, value := range newMap {
-			oldMap[key] = value
-		}
-	}
-
-	mergeStorageDiffs := func(oldMap, newMap map[felt.Felt]map[felt.Felt]*felt.Felt) {
-		for addr, newAddrStorage := range newMap {
-			if oldAddrStorage, exists := oldMap[addr]; exists {
-				mergeMaps(oldAddrStorage, newAddrStorage)
-			} else {
-				oldMap[addr] = newAddrStorage
-			}
-		}
-	}
-
-	mergeStorageDiffs(oldStateDiff.StorageDiffs, newStateDiff.StorageDiffs)
-	mergeMaps(oldStateDiff.Nonces, newStateDiff.Nonces)
-	mergeMaps(oldStateDiff.DeployedContracts, newStateDiff.DeployedContracts)
-	mergeMaps(oldStateDiff.DeclaredV1Classes, newStateDiff.DeclaredV1Classes)
-	mergeMaps(oldStateDiff.ReplacedClasses, newStateDiff.ReplacedClasses)
-	oldStateDiff.DeclaredV0Classes = append(oldStateDiff.DeclaredV0Classes, newStateDiff.DeclaredV0Classes...)
-
-	return oldStateDiff
-}
diff --git a/genesis/genesis.go b/genesis/genesis.go
index 95ae567ac..2f535fca2 100644
--- a/genesis/genesis.go
+++ b/genesis/genesis.go
@@ -19,6 +19,9 @@ import (
 	"github.com/NethermindEth/juno/vm"
 )
 
+// The constructor entrypoint for cairo contracts
+const CONSTRUCTOR_SELECTOR = "0x28ffe4ff0f226a9107253e17a904099aa4f63a02a5621de0576e5aa71bc5194"
+
 type GenesisConfig struct {
 	Classes           []string                          `json:"classes"`            // []path-to-class.json
 	Contracts         map[felt.Felt]GenesisContractData `json:"contracts"`          // address -> {classHash, constructorArgs}
@@ -122,7 +125,7 @@ func GenesisStateDiff( //nolint:funlen,gocyclo
 		}
 	}
 
-	constructorSelector, err := new(felt.Felt).SetString("0x28ffe4ff0f226a9107253e17a904099aa4f63a02a5621de0576e5aa71bc5194")
+	constructorSelector, err := new(felt.Felt).SetString(CONSTRUCTOR_SELECTOR)
 	if err != nil {
 		return nil, nil, fmt.Errorf("convert string to felt: %v", err)
 	}
@@ -210,8 +213,11 @@ func GenesisStateDiff( //nolint:funlen,gocyclo
 
 		traceSD := vm2core.AdaptStateDiff(&trace[0])
 		genesisSD, _ := genesisState.StateDiffAndClasses()
-		mergedSD := core.MergeStateDiffs(genesisSD, traceSD)
-		genesisState.SetStateDiff(mergedSD)
+		fmt.Println("==")
+		fmt.Println(genesisSD)
+		fmt.Println(traceSD)
+		genesisSD.Merge(traceSD)
+		genesisState.SetStateDiff(genesisSD)
 	}
 	genesisStateDiff, genesisClasses := genesisState.StateDiffAndClasses()
 	return genesisStateDiff, genesisClasses, nil