fix epoch_stakes again (#5396)

core/src/consensus.rs

@@ -214,8 +214,7 @@ impl Tower {
     }
 
     pub fn is_recent_epoch(&self, bank: &Bank) -> bool {
-        let bank_epoch = bank.get_epoch_and_slot_index(bank.slot()).0;
-        bank_epoch >= self.epoch_stakes.epoch
+        bank.epoch() >= self.epoch_stakes.epoch
     }
 
     pub fn update_epoch(&mut self, bank: &Bank) {
@@ -224,8 +223,7 @@ impl Tower {
             bank.slot(),
             self.epoch_stakes.epoch
         );
-        let bank_epoch = bank.get_epoch_and_slot_index(bank.slot()).0;
-        if bank_epoch != self.epoch_stakes.epoch {
+        if bank.epoch() != self.epoch_stakes.epoch {
             assert!(
                 self.is_recent_epoch(bank),
                 "epoch_stakes cannot move backwards"

core/src/staking_utils.rs

@@ -150,23 +150,15 @@ pub(crate) mod tests {
 
         // First epoch has the bootstrap leader
         expected.insert(voting_keypair.pubkey(), leader_stake.stake(0));
-        assert_eq!(
-            vote_account_stakes_at_epoch(&bank, 0),
-            Some(expected.clone())
-        );
+
+        // henceforth, verify that we have snapshots of stake at epoch 0
+        let expected = Some(expected);
+        assert_eq!(vote_account_stakes_at_epoch(&bank, 0), expected);
 
         // Second epoch carries same information
         let bank = new_from_parent(&Arc::new(bank), 1);
-        assert_eq!(
-            vote_account_stakes_at_epoch(&bank, 0),
-            Some(expected.clone())
-        );
-
-        expected.insert(voting_keypair.pubkey(), leader_stake.stake(1));
-        assert_eq!(
-            vote_account_stakes_at_epoch(&bank, 1),
-            Some(expected.clone())
-        );
+        assert_eq!(vote_account_stakes_at_epoch(&bank, 0), expected);
+        assert_eq!(vote_account_stakes_at_epoch(&bank, 1), expected);
     }
 
     pub(crate) fn setup_vote_and_stake_accounts(
@@ -233,7 +225,7 @@ pub(crate) mod tests {
             ..
         } = create_genesis_block(10_000);
 
-        let mut bank = Bank::new(&genesis_block);
+        let bank = Bank::new(&genesis_block);
         let vote_pubkey = Pubkey::new_rand();
 
         // Give the validator some stake but don't setup a staking account
@@ -252,23 +244,28 @@ pub(crate) mod tests {
             stake,
         );
 
+        // simulated stake
         let other_stake = Stake {
             stake,
-            activated: bank.get_stakers_epoch(bank.slot()),
+            activated: bank.epoch(),
             ..Stake::default()
         };
 
         let epoch = bank.get_stakers_epoch(bank.slot());
         // find the first slot in the next staker's epoch
-        while bank.epoch() <= epoch {
-            let slot = bank.slot() + 1;
-            bank = new_from_parent(&Arc::new(bank), slot);
+        let mut slot = 1;
+        while bank.get_stakers_epoch(slot) <= epoch {
+            slot += 1;
         }
+        let bank = new_from_parent(&Arc::new(bank), slot);
+        let epoch = bank.get_stakers_epoch(slot);
 
         let result: Vec<_> = epoch_stakes_and_lockouts(&bank, 0);
         assert_eq!(result, vec![(leader_stake.stake(0), None)]);
 
-        let mut result: Vec<_> = epoch_stakes_and_lockouts(&bank, bank.epoch());
+        // epoch stakes and lockouts are saved off for the future epoch, should
+        //  match current bank state
+        let mut result: Vec<_> = epoch_stakes_and_lockouts(&bank, epoch);
         result.sort();
         let mut expected = vec![
             (leader_stake.stake(bank.epoch()), None),

programs/stake_api/src/stake_state.rs

@@ -217,7 +217,7 @@ impl<'a> StakeAccount for KeyedAccount<'a> {
                 new_stake,
                 vote_account.unsigned_key(),
                 &vote_account.state()?,
-                clock.stakers_epoch,
+                clock.epoch,
             );
 
             self.set_state(&StakeState::Stake(stake))
@@ -231,7 +231,7 @@ impl<'a> StakeAccount for KeyedAccount<'a> {
         }
 
         if let StakeState::Stake(mut stake) = self.state()? {
-            stake.deactivate(clock.stakers_epoch);
+            stake.deactivate(clock.epoch);
 
             self.set_state(&StakeState::Stake(stake))
         } else {
@@ -291,7 +291,7 @@ impl<'a> StakeAccount for KeyedAccount<'a> {
                 if stake.deactivated == std::u64::MAX {
                     return Err(InstructionError::InsufficientFunds);
                 }
-                let staked = if stake.stake(clock.stakers_epoch) == 0 {
+                let staked = if stake.stake(clock.epoch) == 0 {
                     0
                 } else {
                     // Assume full stake if the stake is under warmup/cooldown
@@ -358,7 +358,7 @@ mod tests {
     #[test]
     fn test_stake_delegate_stake() {
         let clock = sysvar::clock::Clock {
-            stakers_epoch: 1,
+            epoch: 1,
             ..sysvar::clock::Clock::default()
         };
 
@@ -406,7 +406,7 @@ mod tests {
                 voter_pubkey: vote_keypair.pubkey(),
                 credits_observed: vote_state.credits(),
                 stake: stake_lamports,
-                activated: clock.stakers_epoch,
+                activated: clock.epoch,
                 deactivated: std::u64::MAX,
             })
         );
@@ -464,7 +464,7 @@ mod tests {
             Account::new(stake_lamports, std::mem::size_of::<StakeState>(), &id());
 
         let clock = sysvar::clock::Clock {
-            stakers_epoch: 1,
+            epoch: 1,
             ..sysvar::clock::Clock::default()
         };
 
@@ -548,7 +548,7 @@ mod tests {
         // deactivate the stake before withdrawal
         assert_eq!(stake_keyed_account.deactivate_stake(&clock), Ok(()));
         // simulate time passing
-        clock.stakers_epoch += STAKE_WARMUP_EPOCHS;
+        clock.epoch += STAKE_WARMUP_EPOCHS;
 
         // Try to withdraw more than what's available
         assert_eq!(
@@ -581,7 +581,7 @@ mod tests {
 
         let clock = sysvar::clock::Clock::default();
         let mut future = sysvar::clock::Clock::default();
-        future.stakers_epoch += 16;
+        future.epoch += 16;
 
         let to = Pubkey::new_rand();
         let mut to_account = Account::new(1, 0, &system_program::id());

runtime/src/bank.rs

@@ -301,8 +301,7 @@ impl Bank {
         {
             let stakes = bank.stakes.read().unwrap();
             for epoch in 0..=bank.get_stakers_epoch(bank.slot) {
-                bank.epoch_stakes
-                    .insert(epoch, stakes.clone_with_epoch(epoch));
+                bank.epoch_stakes.insert(epoch, stakes.clone());
             }
         }
         bank.update_clock();
@@ -372,7 +371,7 @@ impl Bank {
             //  if my parent didn't populate for this epoch, we've
             //  crossed a boundary
             if epoch_stakes.get(&epoch).is_none() {
-                epoch_stakes.insert(epoch, self.stakes.read().unwrap().clone_with_epoch(epoch));
+                epoch_stakes.insert(epoch, self.stakes.read().unwrap().clone());
             }
             epoch_stakes
         };
@@ -2488,8 +2487,10 @@ mod tests {
             let vote_accounts = parent.epoch_vote_accounts(epoch);
             assert!(vote_accounts.is_some());
 
+            // epoch_stakes are a snapshot at the stakers_slot_offset boundary
+            //   in the prior epoch (0 in this case)
             assert_eq!(
-                leader_stake.stake(epoch),
+                leader_stake.stake(0),
                 vote_accounts.unwrap().get(&leader_vote_account).unwrap().0
             );
 
@@ -2505,7 +2506,7 @@ mod tests {
 
         assert!(child.epoch_vote_accounts(epoch).is_some());
         assert_eq!(
-            leader_stake.stake(epoch),
+            leader_stake.stake(child.epoch()),
             child
                 .epoch_vote_accounts(epoch)
                 .unwrap()
@@ -2515,13 +2516,22 @@ mod tests {
         );
 
         // child crosses epoch boundary but isn't the first slot in the epoch, still
-        //  makes an epoch stakes
+        //  makes an epoch stakes snapshot at 1
         let child = Bank::new_from_parent(
             &parent,
             &leader_pubkey,
             SLOTS_PER_EPOCH - (STAKERS_SLOT_OFFSET % SLOTS_PER_EPOCH) + 1,
         );
         assert!(child.epoch_vote_accounts(epoch).is_some());
+        assert_eq!(
+            leader_stake.stake(child.epoch()),
+            child
+                .epoch_vote_accounts(epoch)
+                .unwrap()
+                .get(&leader_vote_account)
+                .unwrap()
+                .0
+        );
     }
 
     #[test]