[net processing] Remove fSupportsDesiredCmpctVersion

It is now completely redundant with fProvidesHeadersAndIDs.

Author: jnewbery

src/net_processing.cpp

@@ -371,19 +371,12 @@ struct CNodeState {
     bool fPreferHeaderAndIDs{false};
     /**
       * Whether this peer will send us cmpctblocks if we request them.
-      * This is not used to gate request logic, as we really only care about fSupportsDesiredCmpctVersion,
-      * but is used as a flag to "lock in" the version of compact blocks (fWantsCmpctWitness) we send.
       */
     bool fProvidesHeaderAndIDs{false};
     //! Whether this peer can give us witnesses
     bool fHaveWitness{false};
     //! Whether this peer wants witnesses in cmpctblocks/blocktxns
     bool fWantsCmpctWitness{false};
-    /**
-     * If we've announced NODE_WITNESS to this peer: whether the peer sends witnesses in cmpctblocks/blocktxns,
-     * otherwise: whether this peer sends non-witnesses in cmpctblocks/blocktxns.
-     */
-    bool fSupportsDesiredCmpctVersion{false};
 
     /** State used to enforce CHAIN_SYNC_TIMEOUT and EXTRA_PEER_CHECK_INTERVAL logic.
       *
@@ -976,8 +969,8 @@ void PeerManagerImpl::MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid)
     if (m_ignore_incoming_txs) return;
 
     CNodeState* nodestate = State(nodeid);
-    if (!nodestate || !nodestate->fSupportsDesiredCmpctVersion) {
-        // Never ask from peers who can't provide witnesses.
+    if (!nodestate || !nodestate->fProvidesHeaderAndIDs) {
+        // Don't request compact blocks if the peer has not signalled support
         return;
     }
     if (nodestate->fProvidesHeaderAndIDs) {
@@ -2292,7 +2285,7 @@ void PeerManagerImpl::ProcessHeadersMessage(CNode& pfrom, const Peer& peer,
                 }
                 if (vGetData.size() > 0) {
                     if (!m_ignore_incoming_txs &&
-                        nodestate->fSupportsDesiredCmpctVersion &&
+                        nodestate->fProvidesHeaderAndIDs &&
                         vGetData.size() == 1 &&
                         mapBlocksInFlight.size() == 1 &&
                         pindexLast->pprev->IsValid(BLOCK_VALID_CHAIN)) {
@@ -2899,7 +2892,6 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             // (receiving sendcmpct(1) signals high-bandwidth, sendcmpct(0) low-bandwidth)
             pfrom.m_bip152_highbandwidth_from = fAnnounceUsingCMPCTBLOCK;
         }
-        State(pfrom.GetId())->fSupportsDesiredCmpctVersion = true;
         return;
     }
 
@@ -3625,7 +3617,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             return;
         }
 
-        if (DeploymentActiveAt(*pindex, m_chainman, Consensus::DEPLOYMENT_SEGWIT) && !nodestate->fSupportsDesiredCmpctVersion) {
+        if (DeploymentActiveAt(*pindex, m_chainman, Consensus::DEPLOYMENT_SEGWIT) && !nodestate->fProvidesHeaderAndIDs) {
             // Don't bother trying to process compact blocks from v1 peers
             // after segwit activates.
             return;