From 20242af4e7afd772588bff9d54302a8c906ce0ad Mon Sep 17 00:00:00 2001
From: Mark Tyneway <mark.tyneway@gmail.com>
Date: Wed, 12 May 2021 15:57:43 -0700
Subject: [PATCH] fix: get last confirmed enqueue (#846)

* l2geth: fix get last confirmed enqueue

* chore: add changeset

* client: return error correctly
---
 .changeset/big-moose-type.md | 5 +++++
 l2geth/rollup/client.go      | 9 ++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/big-moose-type.md

diff --git a/.changeset/big-moose-type.md b/.changeset/big-moose-type.md
new file mode 100644
index 000000000..e87e713c4
--- /dev/null
+++ b/.changeset/big-moose-type.md
@@ -0,0 +1,5 @@
+---
+'@eth-optimism/l2geth': patch
+---
+
+Fixes a bug in L2geth that causes it to skip the first deposit if there have been no deposits batch-submitted yet
diff --git a/l2geth/rollup/client.go b/l2geth/rollup/client.go
index 729848017..79045f3dc 100644
--- a/l2geth/rollup/client.go
+++ b/l2geth/rollup/client.go
@@ -449,23 +449,26 @@ func (c *Client) GetLastConfirmedEnqueue() (*types.Transaction, error) {
 	if err != nil {
 		return nil, fmt.Errorf("Cannot get latest enqueue: %w", err)
 	}
-	// This should only happen if the database is empty
+	// This should only happen if there are no L1 to L2 transactions yet
 	if enqueue == nil {
-		return nil, nil
+		return nil, errElementNotFound
 	}
 	// Work backwards looking for the first enqueue
 	// to have an index, which means it has been included
 	// in the canonical transaction chain.
 	for {
 		meta := enqueue.GetMeta()
+		// The enqueue has an index so it has been confirmed
 		if meta.Index != nil {
 			return enqueue, nil
 		}
+		// There is no queue index so this is a bug
 		if meta.QueueIndex == nil {
 			return nil, fmt.Errorf("queue index is nil")
 		}
+		// No enqueue transactions have been confirmed yet
 		if *meta.QueueIndex == uint64(0) {
-			return enqueue, nil
+			return nil, errElementNotFound
 		}
 		next, err := c.GetEnqueue(*meta.QueueIndex - 1)
 		if err != nil {