fix(fetcher): l1_head < latest l1 header (#269)

* fix: safe head range calc

* feat: add

* Fix

utils/host/src/block_range.rs

@@ -162,7 +162,7 @@ pub async fn split_range_based_on_safe_heads(
 
     // Loop over all of the safe heads and create ranges.
     for safe_head in safe_heads {
-        if safe_head > current_l2_start {
+        if safe_head > current_l2_start && current_l2_start < l2_end {
             let mut range_start = current_l2_start;
             while range_start + max_range_size < min(l2_end, safe_head) {
                 ranges.push(SpanBatchRange {

utils/host/src/fetcher.rs

@@ -767,7 +767,16 @@ impl OPSuccinctDataFetcher {
         };
         let claimed_l2_output_root = keccak256(l2_claim_encoded.abi_encode());
 
-        let (l1_head_hash, _) = self.get_l1_head(l2_end_block).await?;
+        let (_, l1_head_number) = self.get_l1_head(l2_end_block).await?;
+
+        // FIXME: Investigate requirement for L1 head offset beyond batch posting block with safe head > L2 end block.
+        let l1_head_number = l1_head_number + 20;
+        // The new L1 header requested should not be greater than the latest L1 header.
+        let latest_l1_header = self.get_l1_header(BlockId::latest()).await?;
+        let l1_head_hash = match l1_head_number > latest_l1_header.number {
+            true => latest_l1_header.hash_slow(),
+            false => self.get_l1_header(l1_head_number.into()).await?.hash_slow(),
+        };
 
         // Get the workspace root, which is where the data directory is.
         let data_directory =
@@ -887,7 +896,7 @@ impl OPSuccinctDataFetcher {
                 )
                 .await?;
             let l2_safe_head = result.safe_head.number;
-            // If the safe head is greater than or equal to the L2 end block at this L1 block, then we can derive the L2 end block from this L1 block.
+            // If the safe head is GTE to the L2 end block at this L1 block, then we can derive the L2 end block from this L1 block.
             if l2_safe_head >= l2_end_block {
                 return Ok((result.l1_block.hash, result.l1_block.number));
             }