consensus: gate RNG substates by amendment state

src/xrpld/app/consensus/RCLConsensus.cpp

@@ -1150,6 +1150,12 @@ RCLConsensus::Adaptor::preStartRound(
     RCLCxLedger const& prevLgr,
     hash_set<NodeID> const& nowTrusted)
 {
+    rngEnabledThisRound_ =
+        prevLgr.ledger_->rules().enabled(featureConsensusEntropy);
+
+    JLOG(j_.debug()) << "RNGGATE: preStartRound prevSeq=" << prevLgr.seq()
+                     << " rulesEnabled=" << rngEnabledThisRound_;
+
     // We have a key, we do not want out of sync validations after a restart
     // and are not amendment blocked.
     validating_ = validatorKeys_.keys &&
@@ -1384,6 +1390,12 @@ RCLConsensus::Adaptor::hasAnyReveals() const
     return !pendingReveals_.empty();
 }
 
+bool
+RCLConsensus::Adaptor::rngEnabled() const
+{
+    return rngEnabledThisRound_;
+}
+
 bool
 RCLConsensus::Adaptor::shouldSendExplicitFinalProposal() const
 {
@@ -1676,6 +1688,11 @@ RCLConsensus::Adaptor::clearRngState()
     expectedProposers_.clear();
     commitProofs_.clear();
     proposalProofs_.clear();
+    // Keep the round-level enable latch intact here. Consensus::startRound()
+    // calls preStartRound() first to snapshot whether RNG is enabled for the
+    // upcoming round, then immediately clears per-round working state.
+    // Resetting rngEnabledThisRound_ here would wipe that snapshot before
+    // phaseEstablish() can consult it.
 }
 
 void

src/xrpld/app/consensus/RCLConsensus.h

@@ -105,6 +105,7 @@ class RCLConsensus
         // Ephemeral entropy secret (in-memory only, crash = non-revealer)
         uint256 myEntropySecret_;
         bool entropyFailed_ = false;
+        bool rngEnabledThisRound_ = false;
 
         // Real SHAMaps for the current round (unbacked, ephemeral)
         std::shared_ptr<SHAMap> commitSetMap_;
@@ -267,6 +268,15 @@ class RCLConsensus
         bool
         hasAnyReveals() const;
 
+        /** Whether ConsensusEntropy is enabled for the current round.
+
+            Latched from the previous ledger's rules at round start so the
+            generic consensus engine can skip RNG-specific waiting paths when
+            the amendment is inactive.
+        */
+        bool
+        rngEnabled() const;
+
         /** Whether to send an explicit final proposal (seq=4 style). */
         bool
         shouldSendExplicitFinalProposal() const;