Remove SSZ Union usage in BlockHeaderWithProof type

Remove SSZ Union in BlockHeaderWithProof type by making the proof
an SSZ encoded ByteList. The right type for the proof can be
selected at the decoding step by first looking into the header
for the timestamp and selecting the right type based on the
hardfork the block is in.

fluffy/network/history/content/content_values.nim

@@ -26,25 +26,15 @@ const
   MAX_WITHDRAWALS_COUNT = MAX_WITHDRAWALS_PER_PAYLOAD
 
   MAX_EPHEMERAL_HEADER_PAYLOAD = 256
+  MAX_HEADER_PROOF_LENGTH* = 1024
 
 type
   ## BlockHeader types
   HistoricalHashesAccumulatorProof* = array[15, Digest]
 
-  BlockHeaderProofType* = enum
-    none = 0x00 # An SSZ Union None
-    historicalHashesAccumulatorProof = 0x01
-
-  BlockHeaderProof* = object
-    case proofType*: BlockHeaderProofType
-    of none:
-      discard
-    of historicalHashesAccumulatorProof:
-      historicalHashesAccumulatorProof*: HistoricalHashesAccumulatorProof
-
   BlockHeaderWithProof* = object
     header*: ByteList[MAX_HEADER_LENGTH] # RLP data
-    proof*: BlockHeaderProof
+    proof*: ByteList[MAX_HEADER_PROOF_LENGTH]
 
   ## Ephemeral BlockHeader list
   EphemeralBlockHeaderList* =
@@ -73,11 +63,3 @@ type
   ## Receipts types
   ReceiptByteList* = ByteList[MAX_RECEIPT_LENGTH] # RLP data
   PortalReceipts* = List[ReceiptByteList, MAX_TRANSACTION_COUNT]
-
-func init*(T: type BlockHeaderProof, proof: HistoricalHashesAccumulatorProof): T =
-  BlockHeaderProof(
-    proofType: historicalHashesAccumulatorProof, historicalHashesAccumulatorProof: proof
-  )
-
-func init*(T: type BlockHeaderProof): T =
-  BlockHeaderProof(proofType: none)

fluffy/network/history/history_validation.nim

@@ -50,20 +50,23 @@ func validateHeaderBytes*(
   ok(header)
 
 func verifyBlockHeaderProof*(
-    a: FinishedHistoricalHashesAccumulator, header: Header, proof: BlockHeaderProof
+    a: FinishedHistoricalHashesAccumulator,
+    header: Header,
+    proof: ByteList[MAX_HEADER_PROOF_LENGTH],
 ): Result[void, string] =
-  case proof.proofType
-  of BlockHeaderProofType.historicalHashesAccumulatorProof:
-    a.verifyAccumulatorProof(header, proof.historicalHashesAccumulatorProof)
-  of BlockHeaderProofType.none:
-    if header.isPreMerge():
-      err("Pre merge header requires HistoricalHashesAccumulatorProof")
-    else:
-      # TODO:
-      # Add verification post merge based on historical_roots & historical_summaries
-      # Lets for now no longer accept other headers without a proof and the most
-      # recent ones are now a different type.
-      err("Post merge header proofs not yet activated")
+  let timestamp = Moment.init(header.timestamp.int64, Second)
+
+  if isShanghai(chainConfig, timestamp):
+    # TODO: Add verification post merge based on historical_summaries
+    err("Shanghai block verification not implemented")
+  elif isPoSBlock(chainConfig, header.number):
+    # TODO: Add verification post merge based on historical_roots
+    err("PoS block verification not implemented")
+  else:
+    let accumulatorProof = decodeSsz(proof.asSeq(), HistoricalHashesAccumulatorProof).valueOr:
+      return err("Failed decoding accumulator proof: " & error)
+
+    a.verifyAccumulatorProof(header, accumulatorProof)
 
 func validateCanonicalHeaderBytes*(
     bytes: openArray[byte], id: uint64 | Hash32, a: FinishedHistoricalHashesAccumulator

fluffy/network/history/validation/historical_hashes_accumulator.nim

@@ -1,5 +1,5 @@
 # Nimbus
-# Copyright (c) 2022-2024 Status Research & Development GmbH
+# Copyright (c) 2022-2025 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -198,7 +198,7 @@ func buildHeaderWithProof*(
 
   ok(
     BlockHeaderWithProof(
-      header: ByteList[2048].init(rlp.encode(header)),
-      proof: BlockHeaderProof.init(proof),
+      header: ByteList[MAX_HEADER_LENGTH].init(rlp.encode(header)),
+      proof: ByteList[MAX_HEADER_PROOF_LENGTH].init(SSZ.encode(proof)),
     )
   )

fluffy/tests/rpc_tests/test_portal_rpc_client.nim

@@ -1,5 +1,5 @@
 # Nimbus - Portal Network
-# Copyright (c) 2021-2024 Status Research & Development GmbH
+# Copyright (c) 2021-2025 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -63,7 +63,8 @@ proc store*(hn: HistoryNode, blockHash: Hash32, blockHeader: Header) =
   let
     headerRlp = rlp.encode(blockHeader)
     blockHeaderWithProof = BlockHeaderWithProof(
-      header: ByteList[2048].init(headerRlp), proof: BlockHeaderProof.init()
+      header: ByteList[MAX_HEADER_LENGTH].init(headerRlp),
+      proof: ByteList[MAX_HEADER_PROOF_LENGTH].init(@[]),
     )
     contentKeyBytes = blockHeaderContentKey(blockHash).encode()
     contentId = history_content.toContentId(contentKeyBytes)

fluffy/tests/state_network_tests/state_test_helpers.nim

@@ -1,5 +1,5 @@
 # Fluffy
-# Copyright (c) 2021-2024 Status Research & Development GmbH
+# Copyright (c) 2021-2025 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -154,7 +154,8 @@ proc mockStateRootLookup*(
     blockHeader = Header(stateRoot: stateRoot)
     headerRlp = rlp.encode(blockHeader)
     blockHeaderWithProof = BlockHeaderWithProof(
-      header: ByteList[2048].init(headerRlp), proof: BlockHeaderProof.init()
+      header: ByteList[MAX_HEADER_LENGTH].init(headerRlp),
+      proof: ByteList[MAX_HEADER_PROOF_LENGTH].init(@[]),
     )
     contentKeyBytes = blockHeaderContentKey(blockNumOrHash).encode()
     contentId = history_content.toContentId(contentKeyBytes)