op-batcher: extract state pruning, block fetching and progress checking into a single pure function

op-batcher/batcher/sync_actions.go

@@ -27,7 +27,7 @@ type syncActions struct {
 
 func (s syncActions) String() string {
 	return fmt.Sprintf(
-		"SyncActions{blocksToPrune: %d, channelsToPrune: %d, clearState: %v, blocksToLoad: [%d, %d]}", s.blocksToPrune, s.channelsToPrune, s.clearState, s.blocksToLoad.start, s.blocksToLoad.end)
+		"SyncActions{blocksToPrune: %d, channelsToPrune: %d, clearState: %v, blocksToLoad: [%v]}", s.blocksToPrune, s.channelsToPrune, s.clearState, s.blocksToLoad)
 }
 
 // computeSyncActions determines the actions that should be taken based on the inputs provided. The inputs are the current

op-batcher/batcher/sync_actions_test.go

@@ -179,6 +179,20 @@ func TestBatchSubmitter_computeSyncActions(t *testing.T) {
 				blocksToLoad:    &inclusiveBlockRange{104, 109},
 			},
 		},
+		{name: "no blocks",
+			newSyncStatus: eth.SyncStatus{
+				HeadL1:    eth.BlockRef{Number: 5},
+				CurrentL1: eth.BlockRef{Number: 2},
+				SafeL2:    eth.L2BlockRef{Number: 103, Hash: block103.Hash()},
+				UnsafeL2:  eth.L2BlockRef{Number: 109},
+			},
+			prevCurrentL1: eth.BlockRef{Number: 1},
+			blocks:        queue.Queue[*types.Block]{},
+			channels:      []channelStatuser{},
+			expected: syncActions{
+				blocksToLoad: &inclusiveBlockRange{104, 109},
+			},
+		},
 		{name: "happy path + multiple channels",
 			newSyncStatus: eth.SyncStatus{
 				HeadL1:    eth.BlockRef{Number: 5},