v1.18: vote: deprecate unused legacy vote tx plumbing (backport of #274…

…) (#276)

* vote: deprecate unused legacy vote tx plumbing (#274)

(cherry picked from commit b27c80a)

# Conflicts:
#	sdk/src/feature_set.rs

* fix conflicts

---------

Co-authored-by: Ashwin Sekar <ashwin@anza.xyz>
Co-authored-by: Ashwin Sekar <ashwin@solana.com>

programs/vote/benches/process_vote.rs

@@ -48,7 +48,7 @@ fn create_accounts() -> (Slot, SlotHashes, Vec<TransactionAccount>, Vec<AccountM
         );
 
         for next_vote_slot in 0..num_initial_votes {
-            vote_state.process_next_vote_slot(next_vote_slot, 0, 0);
+            vote_state.process_next_vote_slot(next_vote_slot, 0, 0, true, true);
         }
         let mut vote_account_data: Vec<u8> = vec![0; VoteState::size_of()];
         let versioned = VoteStateVersions::new_current(vote_state);

programs/vote/src/vote_state/mod.rs

@@ -612,6 +612,9 @@ pub fn process_new_vote_state(
     let timely_vote_credits = feature_set.map_or(false, |f| {
         f.is_active(&feature_set::timely_vote_credits::id())
     });
+    let deprecate_unused_legacy_vote_plumbing = feature_set.map_or(false, |f| {
+        f.is_active(&feature_set::deprecate_unused_legacy_vote_plumbing::id())
+    });
     let mut earned_credits = if timely_vote_credits { 0_u64 } else { 1_u64 };
 
     if let Some(new_root) = new_root {
@@ -621,7 +624,11 @@ pub fn process_new_vote_state(
             if current_vote.slot() <= new_root {
                 if timely_vote_credits || (current_vote.slot() != new_root) {
                     earned_credits = earned_credits
-                        .checked_add(vote_state.credits_for_vote_at_index(current_vote_state_index))
+                        .checked_add(vote_state.credits_for_vote_at_index(
+                            current_vote_state_index,
+                            timely_vote_credits,
+                            deprecate_unused_legacy_vote_plumbing,
+                        ))
                         .expect("`earned_credits` does not overflow");
                 }
                 current_vote_state_index = current_vote_state_index
@@ -734,11 +741,19 @@ pub fn process_vote_unfiltered(
     slot_hashes: &[SlotHash],
     epoch: Epoch,
     current_slot: Slot,
+    timely_vote_credits: bool,
+    deprecate_unused_legacy_vote_plumbing: bool,
 ) -> Result<(), VoteError> {
     check_slots_are_valid(vote_state, vote_slots, &vote.hash, slot_hashes)?;
-    vote_slots
-        .iter()
-        .for_each(|s| vote_state.process_next_vote_slot(*s, epoch, current_slot));
+    vote_slots.iter().for_each(|s| {
+        vote_state.process_next_vote_slot(
+            *s,
+            epoch,
+            current_slot,
+            timely_vote_credits,
+            deprecate_unused_legacy_vote_plumbing,
+        )
+    });
     Ok(())
 }
 
@@ -748,6 +763,8 @@ pub fn process_vote(
     slot_hashes: &[SlotHash],
     epoch: Epoch,
     current_slot: Slot,
+    timely_vote_credits: bool,
+    deprecate_unused_legacy_vote_plumbing: bool,
 ) -> Result<(), VoteError> {
     if vote.slots.is_empty() {
         return Err(VoteError::EmptySlots);
@@ -769,6 +786,8 @@ pub fn process_vote(
         slot_hashes,
         epoch,
         current_slot,
+        timely_vote_credits,
+        deprecate_unused_legacy_vote_plumbing,
     )
 }
 
@@ -785,6 +804,8 @@ pub fn process_vote_unchecked(vote_state: &mut VoteState, vote: Vote) -> Result<
         &slot_hashes,
         vote_state.current_epoch(),
         0,
+        true,
+        true,
     )
 }
 
@@ -1067,7 +1088,18 @@ pub fn process_vote_with_account<S: std::hash::BuildHasher>(
 ) -> Result<(), InstructionError> {
     let mut vote_state = verify_and_get_vote_state(vote_account, clock, signers)?;
 
-    process_vote(&mut vote_state, vote, slot_hashes, clock.epoch, clock.slot)?;
+    let timely_vote_credits = feature_set.is_active(&feature_set::timely_vote_credits::id());
+    let deprecate_unused_legacy_vote_plumbing =
+        feature_set.is_active(&feature_set::deprecate_unused_legacy_vote_plumbing::id());
+    process_vote(
+        &mut vote_state,
+        vote,
+        slot_hashes,
+        clock.epoch,
+        clock.slot,
+        timely_vote_credits,
+        deprecate_unused_legacy_vote_plumbing,
+    )?;
     if let Some(timestamp) = vote.timestamp {
         vote.slots
             .iter()
@@ -1250,7 +1282,7 @@ mod tests {
             134, 135,
         ]
         .into_iter()
-        .for_each(|v| vote_state.process_next_vote_slot(v, 4, 0));
+        .for_each(|v| vote_state.process_next_vote_slot(v, 4, 0, false, true));
 
         let version1_14_11_serialized = bincode::serialize(&VoteStateVersions::V1_14_11(Box::new(
             VoteState1_14_11::from(vote_state.clone()),
@@ -1732,11 +1764,11 @@ mod tests {
         let slot_hashes: Vec<_> = vote.slots.iter().rev().map(|x| (*x, vote.hash)).collect();
 
         assert_eq!(
-            process_vote(&mut vote_state_a, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state_a, &vote, &slot_hashes, 0, 0, true, true),
             Ok(())
         );
         assert_eq!(
-            process_vote(&mut vote_state_b, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state_b, &vote, &slot_hashes, 0, 0, true, true),
             Ok(())
         );
         assert_eq!(recent_votes(&vote_state_a), recent_votes(&vote_state_b));
@@ -1749,12 +1781,12 @@ mod tests {
         let vote = Vote::new(vec![0], Hash::default());
         let slot_hashes: Vec<_> = vec![(0, vote.hash)];
         assert_eq!(
-            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0, true, true),
             Ok(())
         );
         let recent = recent_votes(&vote_state);
         assert_eq!(
-            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0, true, true),
             Err(VoteError::VoteTooOld)
         );
         assert_eq!(recent, recent_votes(&vote_state));
@@ -1814,7 +1846,7 @@ mod tests {
         let vote = Vote::new(vec![0], Hash::default());
         let slot_hashes: Vec<_> = vec![(*vote.slots.last().unwrap(), vote.hash)];
         assert_eq!(
-            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0, true, true),
             Ok(())
         );
         assert_eq!(
@@ -1830,7 +1862,7 @@ mod tests {
         let vote = Vote::new(vec![0], Hash::default());
         let slot_hashes: Vec<_> = vec![(*vote.slots.last().unwrap(), vote.hash)];
         assert_eq!(
-            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0, true, true),
             Ok(())
         );
 
@@ -1849,7 +1881,7 @@ mod tests {
         let vote = Vote::new(vec![0], Hash::default());
         let slot_hashes: Vec<_> = vec![(*vote.slots.last().unwrap(), vote.hash)];
         assert_eq!(
-            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0, true, true),
             Ok(())
         );
 
@@ -1866,7 +1898,7 @@ mod tests {
 
         let vote = Vote::new(vec![], Hash::default());
         assert_eq!(
-            process_vote(&mut vote_state, &vote, &[], 0, 0),
+            process_vote(&mut vote_state, &vote, &[], 0, 0, true, true),
             Err(VoteError::EmptySlots)
         );
     }
@@ -2122,7 +2154,9 @@ mod tests {
                         &vote,
                         &slot_hashes,
                         0,
-                        vote_group.1 // vote_group.1 is the slot in which the vote was cast
+                        vote_group.1, // vote_group.1 is the slot in which the vote was cast
+                        true,
+                        true
                     ),
                     Ok(())
                 );
@@ -3014,7 +3048,7 @@ mod tests {
         // error with `VotesTooOldAllFiltered`
         let slot_hashes = vec![(3, Hash::new_unique()), (2, Hash::new_unique())];
         assert_eq!(
-            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0),
+            process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0, true, true),
             Err(VoteError::VotesTooOldAllFiltered)
         );
 
@@ -3028,7 +3062,7 @@ mod tests {
             .1;
 
         let vote = Vote::new(vec![old_vote_slot, vote_slot], vote_slot_hash);
-        process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0).unwrap();
+        process_vote(&mut vote_state, &vote, &slot_hashes, 0, 0, true, true).unwrap();
         assert_eq!(
             vote_state
                 .votes
@@ -3057,8 +3091,17 @@ mod tests {
                 .unwrap()
                 .1;
             let vote = Vote::new(vote_slots, vote_hash);
-            process_vote_unfiltered(&mut vote_state, &vote.slots, &vote, slot_hashes, 0, 0)
-                .unwrap();
+            process_vote_unfiltered(
+                &mut vote_state,
+                &vote.slots,
+                &vote,
+                slot_hashes,
+                0,
+                0,
+                true,
+                true,
+            )
+            .unwrap();
         }
 
         vote_state

sdk/program/src/vote/state/mod.rs

@@ -448,6 +448,8 @@ impl VoteState {
         next_vote_slot: Slot,
         epoch: Epoch,
         current_slot: Slot,
+        timely_vote_credits: bool,
+        deprecate_unused_legacy_vote_plumbing: bool,
     ) {
         // Ignore votes for slots earlier than we already have votes for
         if self
@@ -460,13 +462,21 @@ impl VoteState {
         self.pop_expired_votes(next_vote_slot);
 
         let landed_vote = LandedVote {
-            latency: Self::compute_vote_latency(next_vote_slot, current_slot),
+            latency: if timely_vote_credits || !deprecate_unused_legacy_vote_plumbing {
+                Self::compute_vote_latency(next_vote_slot, current_slot)
+            } else {
+                0
+            },
             lockout: Lockout::new(next_vote_slot),
         };
 
         // Once the stack is full, pop the oldest lockout and distribute rewards
         if self.votes.len() == MAX_LOCKOUT_HISTORY {
-            let credits = self.credits_for_vote_at_index(0);
+            let credits = self.credits_for_vote_at_index(
+                0,
+                timely_vote_credits,
+                deprecate_unused_legacy_vote_plumbing,
+            );
             let landed_vote = self.votes.pop_front().unwrap();
             self.root_slot = Some(landed_vote.slot());
 
@@ -511,15 +521,20 @@ impl VoteState {
     }
 
     /// Returns the credits to award for a vote at the given lockout slot index
-    pub fn credits_for_vote_at_index(&self, index: usize) -> u64 {
+    pub fn credits_for_vote_at_index(
+        &self,
+        index: usize,
+        timely_vote_credits: bool,
+        deprecate_unused_legacy_vote_plumbing: bool,
+    ) -> u64 {
         let latency = self
             .votes
             .get(index)
             .map_or(0, |landed_vote| landed_vote.latency);
 
         // If latency is 0, this means that the Lockout was created and stored from a software version that did not
         // store vote latencies; in this case, 1 credit is awarded
-        if latency == 0 {
+        if latency == 0 || (deprecate_unused_legacy_vote_plumbing && !timely_vote_credits) {
             1
         } else {
             match latency.checked_sub(VOTE_CREDITS_GRACE_SLOTS) {

sdk/src/feature_set.rs

@@ -780,6 +780,10 @@ pub mod enable_chained_merkle_shreds {
     solana_sdk::declare_id!("7uZBkJXJ1HkuP6R3MJfZs7mLwymBcDbKdqbF51ZWLier");
 }
 
+pub mod deprecate_unused_legacy_vote_plumbing {
+    solana_sdk::declare_id!("6Uf8S75PVh91MYgPQSHnjRAPQq6an5BDv9vomrCwDqLe");
+}
+
 lazy_static! {
     /// Map of feature identifiers to user-visible description
     pub static ref FEATURE_NAMES: HashMap<Pubkey, &'static str> = [
@@ -970,6 +974,7 @@ lazy_static! {
         (cost_model_requested_write_lock_cost::id(), "cost model uses number of requested write locks #34819"),
         (enable_gossip_duplicate_proof_ingestion::id(), "enable gossip duplicate proof ingestion #32963"),
         (enable_chained_merkle_shreds::id(), "Enable chained Merkle shreds #34916"),
+        (deprecate_unused_legacy_vote_plumbing::id(), "Deprecate unused legacy vote tx plumbing"),
         /*************** ADD NEW FEATURES HERE ***************/
     ]
     .iter()