Clean up credits_auto_rewind feature (#32211)

* Remove credits_auto_rewind feature logic from stake program

* Obey clean-up orders

* Clippy prefers this match

* Remove credits_auto_rewind feature helpers from Bank

* Comment nit for language, and shrink to fit on one line

programs/stake/src/stake_state.rs

@@ -33,7 +33,7 @@ use {
         },
     },
     solana_vote_program::vote_state::{self, VoteState, VoteStateVersions},
-    std::{collections::HashSet, convert::TryFrom},
+    std::{cmp::Ordering, collections::HashSet, convert::TryFrom},
 };
 
 #[derive(Debug)]
@@ -183,7 +183,6 @@ fn redeem_stake_rewards(
     vote_state: &VoteState,
     stake_history: Option<&StakeHistory>,
     inflation_point_calc_tracer: Option<impl Fn(&InflationPointCalculationEvent)>,
-    credits_auto_rewind: bool,
 ) -> Option<(u64, u64)> {
     if let Some(inflation_point_calc_tracer) = inflation_point_calc_tracer.as_ref() {
         inflation_point_calc_tracer(&InflationPointCalculationEvent::CreditsObserved(
@@ -198,7 +197,6 @@ fn redeem_stake_rewards(
         vote_state,
         stake_history,
         inflation_point_calc_tracer.as_ref(),
-        credits_auto_rewind,
     )
     .map(|calculated_stake_rewards| {
         if let Some(inflation_point_calc_tracer) = inflation_point_calc_tracer {
@@ -227,8 +225,6 @@ fn calculate_stake_points(
         vote_state,
         stake_history,
         inflation_point_calc_tracer,
-        true, // this is safe because this flag shouldn't affect the
-              // `points` field of the returned struct in any way
     )
     .points
 }
@@ -248,13 +244,12 @@ fn calculate_stake_points_and_credits(
     new_vote_state: &VoteState,
     stake_history: Option<&StakeHistory>,
     inflation_point_calc_tracer: Option<impl Fn(&InflationPointCalculationEvent)>,
-    credits_auto_rewind: bool,
 ) -> CalculatedStakePoints {
     let credits_in_stake = stake.credits_observed;
     let credits_in_vote = new_vote_state.credits();
     // if there is no newer credits since observed, return no point
-    if credits_in_vote <= credits_in_stake {
+    match credits_in_vote.cmp(&credits_in_stake) {
-        if credits_auto_rewind && credits_in_vote < credits_in_stake {
+        Ordering::Less => {
             if let Some(inflation_point_calc_tracer) = inflation_point_calc_tracer.as_ref() {
                 inflation_point_calc_tracer(&SkippedReason::ZeroCreditsAndReturnRewinded.into());
             }
@@ -281,22 +276,19 @@ fn calculate_stake_points_and_credits(
                 new_credits_observed: credits_in_vote,
                 force_credits_update_with_skipped_reward: true,
             };
-        } else {
+        }
-            // change the above `else` to `else if credits_in_vote == credits_in_stake`
+        Ordering::Equal => {
-            // (and remove the outermost enclosing `if`) when cleaning credits_auto_rewind
-            // after activation
-
             if let Some(inflation_point_calc_tracer) = inflation_point_calc_tracer.as_ref() {
                 inflation_point_calc_tracer(&SkippedReason::ZeroCreditsAndReturnCurrent.into());
             }
-            // don't hint the caller and return current value if credits_auto_rewind is off or
+            // don't hint caller and return current value if credits remain unchanged (= delinquent)
-            // credits remain to be unchanged (= delinquent)
             return CalculatedStakePoints {
                 points: 0,
                 new_credits_observed: credits_in_stake,
                 force_credits_update_with_skipped_reward: false,
             };
-        };
+        }
+        Ordering::Greater => {}
     }
 
     let mut points = 0;
@@ -366,7 +358,6 @@ fn calculate_stake_rewards(
     vote_state: &VoteState,
     stake_history: Option<&StakeHistory>,
     inflation_point_calc_tracer: Option<impl Fn(&InflationPointCalculationEvent)>,
-    credits_auto_rewind: bool,
 ) -> Option<CalculatedStakeRewards> {
     // ensure to run to trigger (optional) inflation_point_calc_tracer
     let CalculatedStakePoints {
@@ -378,7 +369,6 @@ fn calculate_stake_rewards(
         vote_state,
         stake_history,
         inflation_point_calc_tracer.as_ref(),
-        credits_auto_rewind,
     );
 
     // Drive credits_observed forward unconditionally when rewards are disabled
@@ -1554,7 +1544,6 @@ pub fn redeem_rewards(
     point_value: &PointValue,
     stake_history: Option<&StakeHistory>,
     inflation_point_calc_tracer: Option<impl Fn(&InflationPointCalculationEvent)>,
-    credits_auto_rewind: bool,
 ) -> Result<(u64, u64), InstructionError> {
     if let StakeState::Stake(meta, mut stake) = stake_state {
         if let Some(inflation_point_calc_tracer) = inflation_point_calc_tracer.as_ref() {
@@ -1578,7 +1567,6 @@ pub fn redeem_rewards(
             vote_state,
             stake_history,
             inflation_point_calc_tracer,
-            credits_auto_rewind,
         ) {
             stake_account.checked_add_lamports(stakers_reward)?;
             stake_account.set_state(&StakeState::Stake(meta, stake))?;
@@ -2510,7 +2498,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2531,7 +2518,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2569,7 +2555,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2613,7 +2598,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2638,7 +2622,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2660,7 +2643,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2685,7 +2667,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2708,7 +2689,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2733,7 +2713,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2752,7 +2731,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
         vote_state.commission = 99;
@@ -2768,7 +2746,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2791,7 +2768,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2814,7 +2790,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2824,21 +2799,12 @@ mod tests {
                 new_credits_observed: 4,
                 force_credits_update_with_skipped_reward: false,
             },
-            calculate_stake_points_and_credits(&stake, &vote_state, None, null_tracer(), true)
+            calculate_stake_points_and_credits(&stake, &vote_state, None, null_tracer())
         );
 
         // credits_observed is auto-rewinded when vote_state credits are assumed to have been
         // recreated
         stake.credits_observed = 1000;
-        // this is old behavior; return the pre-recreation (large) credits from stake account
-        assert_eq!(
-            CalculatedStakePoints {
-                points: 0,
-                new_credits_observed: 1000,
-                force_credits_update_with_skipped_reward: false,
-            },
-            calculate_stake_points_and_credits(&stake, &vote_state, None, null_tracer(), false)
-        );
         // this is new behavior 1; return the post-recreation rewinded credits from the vote account
         assert_eq!(
             CalculatedStakePoints {
@@ -2846,7 +2812,7 @@ mod tests {
                 new_credits_observed: 4,
                 force_credits_update_with_skipped_reward: true,
             },
-            calculate_stake_points_and_credits(&stake, &vote_state, None, null_tracer(), true)
+            calculate_stake_points_and_credits(&stake, &vote_state, None, null_tracer())
         );
         // this is new behavior 2; don't hint when credits both from stake and vote are identical
         stake.credits_observed = 4;
@@ -2856,7 +2822,7 @@ mod tests {
                 new_credits_observed: 4,
                 force_credits_update_with_skipped_reward: false,
             },
-            calculate_stake_points_and_credits(&stake, &vote_state, None, null_tracer(), true)
+            calculate_stake_points_and_credits(&stake, &vote_state, None, null_tracer())
         );
 
         // get rewards and credits observed when not the activation epoch
@@ -2879,7 +2845,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
 
@@ -2903,7 +2868,6 @@ mod tests {
                 &vote_state,
                 None,
                 null_tracer(),
-                true,
             )
         );
     }

runtime/src/bank.rs

@@ -2833,7 +2833,6 @@ impl Bank {
             prev_epoch,
             validator_rewards,
             reward_calc_tracer,
-            self.credits_auto_rewind(),
             thread_pool,
             metrics,
             update_rewards_from_cached_accounts,
@@ -3270,7 +3269,6 @@ impl Bank {
         rewarded_epoch: Epoch,
         rewards: u64,
         reward_calc_tracer: Option<impl RewardCalcTracer>,
-        credits_auto_rewind: bool,
         thread_pool: &ThreadPool,
         metrics: &mut RewardsMetrics,
         update_rewards_from_cached_accounts: bool,
@@ -3296,7 +3294,6 @@ impl Bank {
                 vote_with_stake_delegations_map,
                 rewarded_epoch,
                 point_value,
-                credits_auto_rewind,
                 &stake_history,
                 thread_pool,
                 reward_calc_tracer.as_ref(),
@@ -3578,7 +3575,6 @@ impl Bank {
         reward_calc_tracer: Option<impl RewardCalcTracer>,
         metrics: &mut RewardsMetrics,
     ) -> (VoteRewardsAccounts, StakeRewardCalculation) {
-        let credits_auto_rewind = self.credits_auto_rewind();
         let EpochRewardCalculateParamInfo {
             stake_history,
             stake_delegations,
@@ -3646,7 +3642,6 @@ impl Bank {
                         &point_value,
                         Some(stake_history),
                         reward_calc_tracer.as_ref(),
-                        credits_auto_rewind,
                     );
 
                     let post_lamport = stake_account.lamports();
@@ -3713,7 +3708,6 @@ impl Bank {
         vote_with_stake_delegations_map: DashMap<Pubkey, VoteWithStakeDelegations>,
         rewarded_epoch: Epoch,
         point_value: PointValue,
-        credits_auto_rewind: bool,
         stake_history: &StakeHistory,
         thread_pool: &ThreadPool,
         reward_calc_tracer: Option<impl RewardCalcTracer>,
@@ -3765,7 +3759,6 @@ impl Bank {
                         &point_value,
                         Some(stake_history),
                         reward_calc_tracer.as_ref(),
-                        credits_auto_rewind,
                     );
                     if let Ok((stakers_reward, voters_reward)) = redeemed {
                         // track voter rewards
@@ -8420,11 +8413,6 @@ impl Bank {
             .is_active(&feature_set::prevent_rent_paying_rent_recipients::id())
     }
 
-    pub fn credits_auto_rewind(&self) -> bool {
-        self.feature_set
-            .is_active(&feature_set::credits_auto_rewind::id())
-    }
-
     pub fn read_cost_tracker(&self) -> LockResult<RwLockReadGuard<CostTracker>> {
         self.cost_tracker.read()
     }