sync: remove step from sync client implementation

Deprecated in the spec:
ethereum/consensus-specs#2856 - future PR:s will
deprecate server support as well.

Author: arnetheduck

beacon_chain/sync/sync_manager.nim

@@ -165,9 +165,9 @@ proc getBlocks*[A, B](man: SyncManager[A, B], peer: A,
   try:
     let res =
       if peer.useSyncV2():
-        await beaconBlocksByRange_v2(peer, req.slot, req.count, req.step)
+        await beaconBlocksByRange_v2(peer, req.slot, req.count, 1)
       else:
-        (await beaconBlocksByRange(peer, req.slot, req.count, req.step)).map(
+        (await beaconBlocksByRange(peer, req.slot, req.count, 1)).map(
           proc(blcks: seq[phase0.SignedBeaconBlock]): auto =
             blcks.mapIt(newClone(ForkedSignedBeaconBlock.init(it))))
 

beacon_chain/sync/sync_protocol.nim

@@ -266,6 +266,8 @@ p2pProtocol BeaconSync(version = 1,
     #      client call that returns `seq[ref SignedBeaconBlock]` will
     #      will be generated by the libp2p macro - we guarantee that seq items
     #      are `not-nil` in the implementation
+    # TODO reqStep is deprecated - future versions can remove support for
+    #      values != 1: https://github.com/ethereum/consensus-specs/pull/2856
     trace "got range request", peer, startSlot,
                                count = reqCount, step = reqStep
     if reqCount == 0'u64 or reqStep == 0'u64:
@@ -404,6 +406,8 @@ p2pProtocol BeaconSync(version = 1,
     #      client call that returns `seq[ref ForkedSignedBeaconBlock]` will
     #      will be generated by the libp2p macro - we guarantee that seq items
     #      are `not-nil` in the implementation
+    # TODO reqStep is deprecated - future versions can remove support for
+    #      values != 1: https://github.com/ethereum/consensus-specs/pull/2856
 
     trace "got range request", peer, startSlot,
                                count = reqCount, step = reqStep

beacon_chain/sync/sync_queue.nim

@@ -38,7 +38,6 @@ type
     index*: uint64
     slot*: Slot
     count*: uint64
-    step*: uint64
     item*: T
 
   SyncResult*[T] = object
@@ -105,12 +104,12 @@ proc getShortMap*[T](req: SyncRequest[T],
           break
     else:
       res.add('.')
-    slider = slider + req.step
+    slider = slider + 1
   res
 
 proc contains*[T](req: SyncRequest[T], slot: Slot): bool {.inline.} =
-  slot >= req.slot and slot < req.slot + req.count * req.step and
-    ((slot - req.slot) mod req.step == 0)
+  slot >= req.slot and slot < req.slot + req.count and
+    ((slot - req.slot) == 0)
 
 proc cmp*[T](a, b: SyncRequest[T]): int =
   cmp(uint64(a.slot), uint64(b.slot))
@@ -137,7 +136,7 @@ proc checkResponse*[T](req: SyncRequest[T],
       inc(dindex)
     else:
       return false
-    slot = slot + req.step
+    slot = slot + 1
     rindex = rindex + 1'u64
 
   if dindex == len(data):
@@ -153,26 +152,26 @@ proc getFullMap*[T](req: SyncRequest[T],
 proc init[T](t1: typedesc[SyncRequest], kind: SyncQueueKind, start: Slot,
              finish: Slot, t2: typedesc[T]): SyncRequest[T] =
   let count = finish - start + 1'u64
-  SyncRequest[T](kind: kind, slot: start, count: count, step: 1'u64)
+  SyncRequest[T](kind: kind, slot: start, count: count)
 
 proc init[T](t1: typedesc[SyncRequest], kind: SyncQueueKind, slot: Slot,
              count: uint64, item: T): SyncRequest[T] =
-  SyncRequest[T](kind: kind, slot: slot, count: count, item: item, step: 1'u64)
+  SyncRequest[T](kind: kind, slot: slot, count: count, item: item)
 
 proc init[T](t1: typedesc[SyncRequest], kind: SyncQueueKind, start: Slot,
              finish: Slot, item: T): SyncRequest[T] =
   let count = finish - start + 1'u64
-  SyncRequest[T](kind: kind, slot: start, count: count, step: 1'u64, item: item)
+  SyncRequest[T](kind: kind, slot: start, count: count, item: item)
 
 proc empty*[T](t: typedesc[SyncRequest], kind: SyncQueueKind,
                t2: typedesc[T]): SyncRequest[T] {.inline.} =
-  SyncRequest[T](kind: kind, step: 0'u64, count: 0'u64)
+  SyncRequest[T](kind: kind, count: 0'u64)
 
 proc setItem*[T](sr: var SyncRequest[T], item: T) =
   sr.item = item
 
 proc isEmpty*[T](sr: SyncRequest[T]): bool {.inline.} =
-  (sr.step == 0'u64) and (sr.count == 0'u64)
+  (sr.count == 0'u64)
 
 proc init*[T](t1: typedesc[SyncQueue], t2: typedesc[T],
               queueKind: SyncQueueKind,
@@ -263,8 +262,7 @@ proc `<`*[T](a, b: SyncResult[T]): bool =
     a.request.slot > b.request.slot
 
 proc `==`*[T](a, b: SyncRequest[T]): bool =
-  (a.kind == b.kind) and (a.slot == b.slot) and (a.count == b.count) and
-    (a.step == b.step)
+  (a.kind == b.kind) and (a.slot == b.slot) and (a.count == b.count)
 
 proc lastSlot*[T](req: SyncRequest[T]): Slot =
   ## Returns last slot for request ``req``.
@@ -808,12 +806,10 @@ func updateRequestForNewSafeSlot[T](sq: SyncQueue[T], sr: var SyncRequest[T]) =
       # Request is only partially relevant.
       let
         numSlotsDone = outSlot - lowSlot
-        numStepsDone = (numSlotsDone + sr.step - 1) div sr.step
-      sr.slot += numStepsDone * sr.step
-      sr.count -= numStepsDone
+      sr.slot += numSlotsDone
+      sr.count -= numSlotsDone
     else:
       # Entire request is no longer relevant.
-      sr.step = 0
       sr.count = 0
   of SyncQueueKind.Backward:
     if outSlot >= highSlot:
@@ -823,11 +819,9 @@ func updateRequestForNewSafeSlot[T](sq: SyncQueue[T], sr: var SyncRequest[T]) =
       # Request is only partially relevant.
       let
         numSlotsDone = highSlot - outSlot
-        numStepsDone = (numSlotsDone + sr.step - 1) div sr.step
-      sr.count -= numStepsDone
+      sr.count -= numSlotsDone
     else:
       # Entire request is no longer relevant.
-      sr.step = 0
       sr.count = 0
 
 proc pop*[T](sq: SyncQueue[T], maxslot: Slot, item: T): SyncRequest[T] =