From e7a48a5c08ad2db6bfa171e46407670af0e8430f Mon Sep 17 00:00:00 2001
From: aodhgan <gawnieg@gmail.com>
Date: Wed, 1 Oct 2025 22:41:01 -0700
Subject: [PATCH] move to event driven

---
 internal/ethapi/api.go      | 56 ++++++++++++++++++++++++++-----------
 internal/ethapi/api_test.go |  5 ++--
 2 files changed, 43 insertions(+), 18 deletions(-)

diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 8b28bb7092..e35ffcceac 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -41,6 +41,7 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/eth/gasestimator"
 	"github.com/ethereum/go-ethereum/eth/tracers/logger"
+	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/internal/ethapi/override"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p"
@@ -1653,7 +1654,7 @@ func (api *TransactionAPI) SendRawTransaction(ctx context.Context, input hexutil
 }
 
 // SendRawTransactionSync will add the signed transaction to the transaction pool
-// and wait for the transaction to be mined until the timeout (in milliseconds) is reached.
+// and wait until the transaction has been included in a block and return the receipt, or the timeout.
 func (api *TransactionAPI) SendRawTransactionSync(ctx context.Context, input hexutil.Bytes, timeoutMs *hexutil.Uint64) (map[string]interface{}, error) {
 	tx := new(types.Transaction)
 	if err := tx.UnmarshalBinary(input); err != nil {
@@ -1664,7 +1665,7 @@ func (api *TransactionAPI) SendRawTransactionSync(ctx context.Context, input hex
 		return nil, err
 	}
 
-	// compute effective timeout
+	// effective timeout: min(requested, max), default if none
 	max := api.b.RPCTxSyncMaxTimeout()
 	def := api.b.RPCTxSyncDefaultTimeout()
 
@@ -1674,40 +1675,63 @@ func (api *TransactionAPI) SendRawTransactionSync(ctx context.Context, input hex
 		if req > max {
 			eff = max
 		} else {
-			eff = req // allow shorter than default
+			eff = req
 		}
 	}
 
-	// Wait for receipt until timeout
 	receiptCtx, cancel := context.WithTimeout(ctx, eff)
 	defer cancel()
 
-	ticker := time.NewTicker(time.Millisecond * 100)
-	defer ticker.Stop()
+	// Fast path: maybe already mined/indexed
+	if r, err := api.GetTransactionReceipt(receiptCtx, hash); err == nil && r != nil {
+		return r, nil
+	}
+
+	// Subscribe to head changes and re-check on each new block
+	heads := make(chan core.ChainHeadEvent, 16)
+	var sub event.Subscription = api.b.SubscribeChainHeadEvent(heads)
+	if sub == nil {
+		return nil, errors.New("chain head subscription unavailable")
+	}
+	defer sub.Unsubscribe()
 
 	for {
 		select {
-		case <-ticker.C:
-			receipt, getErr := api.GetTransactionReceipt(receiptCtx, hash)
-			// If tx-index still building, keep polling
-			if getErr != nil && !errors.Is(getErr, NewTxIndexingError()) {
-				// transient or other error: just keep polling
-			}
-			if receipt != nil {
-				return receipt, nil
-			}
 		case <-receiptCtx.Done():
+			// Distinguish upstream cancellation from our timeout
 			if err := ctx.Err(); err != nil {
-				return nil, err // context canceled / deadline exceeded upstream
+				return nil, err
 			}
 			return nil, &txSyncTimeoutError{
 				msg:  fmt.Sprintf("The transaction was added to the transaction pool but wasn't processed in %v.", eff),
 				hash: hash,
 			}
+
+		case err := <-sub.Err():
+			return nil, err
+
+		case <-heads:
+			receipt, getErr := api.GetTransactionReceipt(receiptCtx, hash)
+			// If tx-index still building, keep waiting; ignore transient errors
+			if getErr != nil && !errors.Is(getErr, NewTxIndexingError()) {
+				// ignore and wait for next head
+				continue
+			}
+			if receipt != nil {
+				return receipt, nil
+			}
 		}
 	}
 }
 
+func (api *TransactionAPI) tryGetReceipt(ctx context.Context, hash common.Hash) (map[string]interface{}, error) {
+	receipt, err := api.GetTransactionReceipt(ctx, hash)
+	if err != nil {
+		return nil, err
+	}
+	return receipt, nil
+}
+
 // Sign calculates an ECDSA signature for:
 // keccak256("\x19Ethereum Signed Message:\n" + len(message) + message).
 //
diff --git a/internal/ethapi/api_test.go b/internal/ethapi/api_test.go
index 04ac249e4b..5ee3453a1a 100644
--- a/internal/ethapi/api_test.go
+++ b/internal/ethapi/api_test.go
@@ -448,6 +448,7 @@ type testBackend struct {
 	syncMaxTO     time.Duration
 	sentTx        *types.Transaction
 	sentTxHash    common.Hash
+	headFeed      *event.Feed
 }
 
 func newTestBackend(t *testing.T, n int, gspec *core.Genesis, engine consensus.Engine, generator func(i int, b *core.BlockGen)) *testBackend {
@@ -474,6 +475,7 @@ func newTestBackend(t *testing.T, n int, gspec *core.Genesis, engine consensus.E
 		acc:             acc,
 		pending:         blocks[n],
 		pendingReceipts: receipts[n],
+		headFeed:        new(event.Feed),
 	}
 	return backend
 }
@@ -598,7 +600,7 @@ func (b testBackend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscr
 	panic("implement me")
 }
 func (b testBackend) SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription {
-	panic("implement me")
+	return b.headFeed.Subscribe(ch)
 }
 func (b *testBackend) SendTx(ctx context.Context, tx *types.Transaction) error {
 	b.sentTx = tx
@@ -3959,7 +3961,6 @@ func makeSignedRaw(t *testing.T, api *TransactionAPI, from, to common.Address, v
 func makeSelfSignedRaw(t *testing.T, api *TransactionAPI, addr common.Address) (hexutil.Bytes, *types.Transaction) {
 	return makeSignedRaw(t, api, addr, addr, big.NewInt(0))
 }
-
 func TestSendRawTransactionSync_Success(t *testing.T) {
 	t.Parallel()
 	genesis := &core.Genesis{