Do not use cache map in ChainIDProvider

txmodifier/chainid.go

@@ -3,6 +3,7 @@ package txmodifier
 import (
 	"context"
 	"fmt"
+	"sync"
 
 	"github.com/defiweb/go-eth/rpc"
 	"github.com/defiweb/go-eth/types"
@@ -14,21 +15,27 @@ import (
 // To use this modifier, add it using the WithTXModifiers option when creating
 // a new rpc.Client.
 type ChainIDProvider struct {
-	chainID map[rpc.RPC]uint64
+	mu      sync.Mutex
+	chainID *uint64
 	replace bool
 	cache   bool
 }
 
 // ChainIDProviderOptions is the options for NewChainIDProvider.
 type ChainIDProviderOptions struct {
-	Replace bool // Replace is true if the chain ID should be replaced even if it is already set.
-	Cache   bool // Cache is true if the chain ID will be cached instead of being queried for each transaction.
+	// Replace is true if the transaction chain ID should be replaced even if
+	// it is already set.
+	Replace bool
+
+	// Cache is true if the chain ID will be cached instead of being queried
+	// for each transaction. Cached chain ID will be used for all RPC clients
+	// that use the same ChainIDProvider instance.
+	Cache bool
 }
 
 // NewChainIDProvider returns a new ChainIDProvider.
 func NewChainIDProvider(opts ChainIDProviderOptions) *ChainIDProvider {
 	return &ChainIDProvider{
-		chainID: make(map[rpc.RPC]uint64),
 		replace: opts.Replace,
 		cache:   opts.Cache,
 	}
@@ -39,17 +46,27 @@ func (p *ChainIDProvider) Modify(ctx context.Context, client rpc.RPC, tx *types.
 	if !p.replace && tx.ChainID != nil {
 		return nil
 	}
-	if chainID, ok := p.chainID[client]; ok {
+	if !p.cache {
+		chainID, err := client.ChainID(ctx)
+		if err != nil {
+			return fmt.Errorf("chain ID provider: %w", err)
+		}
 		tx.ChainID = &chainID
 		return nil
 	}
-	chainID, err := client.ChainID(ctx)
-	if err != nil {
-		return fmt.Errorf("chain ID provider: %w", err)
-	}
-	if p.cache {
-		p.chainID[client] = chainID
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	var cid uint64
+	if p.chainID != nil {
+		cid = *p.chainID
+	} else {
+		chainID, err := client.ChainID(ctx)
+		if err != nil {
+			return fmt.Errorf("chain ID provider: %w", err)
+		}
+		p.chainID = &chainID
+		cid = chainID
 	}
-	tx.ChainID = &chainID
+	tx.ChainID = &cid
 	return nil
 }