eth/gasprice/feehistory: support finalized block (ethereum#25442)

eth/gasprice/feehistory.go

@@ -137,44 +137,66 @@ func (oracle *Oracle) processBlock(bf *blockFees, percentiles []float64) {
 // also returned if requested and available.
 // Note: an error is only returned if retrieving the head header has failed. If there are no
 // retrievable blocks in the specified range then zero block count is returned with no error.
-func (oracle *Oracle) resolveBlockRange(ctx context.Context, lastBlock rpc.BlockNumber, blocks int) (*types.Block, []*types.Receipt, uint64, int, error) {
+func (oracle *Oracle) resolveBlockRange(ctx context.Context, reqEnd rpc.BlockNumber, blocks int) (*types.Block, []*types.Receipt, uint64, int, error) {
 	var (
-		headBlock       rpc.BlockNumber
+		headBlock       *types.Header
 		pendingBlock    *types.Block
 		pendingReceipts types.Receipts
+		err             error
 	)
-	// query either pending block or head header and set headBlock
-	if lastBlock == rpc.PendingBlockNumber {
-		if pendingBlock, pendingReceipts = oracle.backend.PendingBlockAndReceipts(); pendingBlock != nil {
-			lastBlock = rpc.BlockNumber(pendingBlock.NumberU64())
-			headBlock = lastBlock - 1
-		} else {
-			// pending block not supported by backend, process until latest block
-			lastBlock = rpc.LatestBlockNumber
-			blocks--
-			if blocks == 0 {
-				return nil, nil, 0, 0, nil
+
+	// Get the chain's current head.
+	if headBlock, err = oracle.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber); err != nil {
+		return nil, nil, 0, 0, err
+	}
+	head := rpc.BlockNumber(headBlock.Number.Uint64())
+
+	// Fail if request block is beyond the chain's current head.
+	if head < reqEnd {
+		return nil, nil, 0, 0, fmt.Errorf("%w: requested %d, head %d", errRequestBeyondHead, reqEnd, head)
+	}
+
+	// Resolve block tag.
+	if reqEnd < 0 {
+		var (
+			resolved *types.Header
+			err      error
+		)
+		switch reqEnd {
+		case rpc.PendingBlockNumber:
+			if pendingBlock, pendingReceipts = oracle.backend.PendingBlockAndReceipts(); pendingBlock != nil {
+				resolved = pendingBlock.Header()
+			} else {
+				// Pending block not supported by backend, process only until latest block.
+				resolved = headBlock
+
+				// Update total blocks to return to account for this.
+				blocks--
 			}
+		case rpc.LatestBlockNumber:
+			// Retrieved above.
+			resolved = headBlock
+		case rpc.CommittedBlockNumber:
+			resolved, err = oracle.backend.HeaderByNumber(ctx, rpc.CommittedBlockNumber)
+		case rpc.EarliestBlockNumber:
+			resolved, err = oracle.backend.HeaderByNumber(ctx, rpc.EarliestBlockNumber)
 		}
-	}
-	if pendingBlock == nil {
-		// if pending block is not fetched then we retrieve the head header to get the head block number
-		if latestHeader, err := oracle.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber); err == nil {
-			headBlock = rpc.BlockNumber(latestHeader.Number.Uint64())
-		} else {
+		if resolved == nil || err != nil {
 			return nil, nil, 0, 0, err
 		}
+		// Absolute number resolved.
+		reqEnd = rpc.BlockNumber(resolved.Number.Uint64())
 	}
-	if lastBlock == rpc.LatestBlockNumber {
-		lastBlock = headBlock
-	} else if pendingBlock == nil && lastBlock > headBlock {
-		return nil, nil, 0, 0, fmt.Errorf("%w: requested %d, head %d", errRequestBeyondHead, lastBlock, headBlock)
+
+	// If there are no blocks to return, short circuit.
+	if blocks == 0 {
+		return nil, nil, 0, 0, nil
 	}
-	// ensure not trying to retrieve before genesis
-	if rpc.BlockNumber(blocks) > lastBlock+1 {
-		blocks = int(lastBlock + 1)
+	// Ensure not trying to retrieve before genesis.
+	if int(reqEnd+1) < blocks {
+		blocks = int(reqEnd + 1)
 	}
-	return pendingBlock, pendingReceipts, uint64(lastBlock), blocks, nil
+	return pendingBlock, pendingReceipts, uint64(reqEnd), blocks, nil
 }
 
 // FeeHistory returns data relevant for fee estimation based on the specified range of blocks.

eth/gasprice/feehistory_test.go

@@ -50,6 +50,7 @@ func TestFeeHistory(t *testing.T) {
 		{false, 1000, 1000, 2, rpc.PendingBlockNumber, nil, 32, 1, nil},
 		{true, 1000, 1000, 2, rpc.PendingBlockNumber, nil, 32, 2, nil},
 		{true, 1000, 1000, 2, rpc.PendingBlockNumber, []float64{0, 10}, 32, 2, nil},
+		{false, 1000, 1000, 2, rpc.CommittedBlockNumber, []float64{0, 10}, 32, 1, nil},
 	}
 	for i, c := range cases {
 		config := Config{

eth/gasprice/gasprice_test.go

@@ -45,6 +45,12 @@ func (b *testBackend) HeaderByNumber(ctx context.Context, number rpc.BlockNumber
 	if number > testHead {
 		return nil, nil
 	}
+	if number == rpc.EarliestBlockNumber {
+		number = 0
+	}
+	if number == rpc.CommittedBlockNumber {
+		return b.chain.CurrentBlock().Header(), nil
+	}
 	if number == rpc.LatestBlockNumber {
 		number = testHead
 	}
@@ -62,6 +68,12 @@ func (b *testBackend) BlockByNumber(ctx context.Context, number rpc.BlockNumber)
 	if number > testHead {
 		return nil, nil
 	}
+	if number == rpc.EarliestBlockNumber {
+		number = 0
+	}
+	if number == rpc.CommittedBlockNumber {
+		return b.chain.CurrentBlock(), nil
+	}
 	if number == rpc.LatestBlockNumber {
 		number = testHead
 	}