v2.0: Simplify RPC partitioned_epoch_reward_enabled determination (ba…

…ckport of #2802) (#2823)

Simplify RPC partitioned_epoch_reward_enabled determination (#2802)

* Check num_reward_partitions for partitioned_epoch_reward_enabled

* Make expect slightly more correct

* Better variable name

(cherry picked from commit 22b823c)

Co-authored-by: Tyera <[email protected]>

rpc/src/rpc.rs

@@ -609,24 +609,6 @@ impl JsonRpcRequestProcessor {
         // epoch
         let bank = self.get_bank_with_config(context_config)?;
 
-        // DO NOT CLEAN UP with feature_set::partitioned_epoch_rewards_superfeature
-        // This logic needs to be retained indefinitely to support historical
-        // rewards before and after feature activation.
-        let partitioned_epoch_reward_enabled_slot = bank
-            .feature_set
-            .activated_slot(&feature_set::partitioned_epoch_rewards_superfeature::id())
-            .or_else(|| {
-                // The order of these checks should not matter, since we will
-                // not ever have both features active on a live cluster. This
-                // check can be removed with
-                // feature_set::enable_partitioned_epoch_reward
-                bank.feature_set
-                    .activated_slot(&feature_set::enable_partitioned_epoch_reward::id())
-            });
-        let partitioned_epoch_reward_enabled = partitioned_epoch_reward_enabled_slot
-            .map(|slot| slot <= first_confirmed_block_in_epoch)
-            .unwrap_or(false);
-
         // Get first block in the epoch
         let Ok(Some(epoch_boundary_block)) = self
             .get_block(
@@ -655,6 +637,8 @@ impl JsonRpcRequestProcessor {
             .into());
         }
 
+        let epoch_has_partitioned_rewards = epoch_boundary_block.num_reward_partitions.is_some();
+
         // Collect rewards from first block in the epoch if partitioned epoch
         // rewards not enabled, or address is a vote account
         let mut reward_map: HashMap<String, (Reward, Slot)> = {
@@ -666,17 +650,17 @@ impl JsonRpcRequestProcessor {
                 &addresses,
                 &|reward_type| -> bool {
                     reward_type == RewardType::Voting
-                        || (!partitioned_epoch_reward_enabled && reward_type == RewardType::Staking)
+                        || (!epoch_has_partitioned_rewards && reward_type == RewardType::Staking)
                 },
             )
         };
 
         // Append stake account rewards from partitions if partitions epoch
         // rewards is enabled
-        if partitioned_epoch_reward_enabled {
+        if epoch_has_partitioned_rewards {
             let num_partitions = epoch_boundary_block.num_reward_partitions.expect(
-                "epoch-boundary block should have num_reward_partitions after partitioned epoch \
-                 rewards enabled",
+                "epoch-boundary block should have num_reward_partitions for epochs with \
+                 partitioned rewards enabled",
             );
 
             let num_partitions = usize::try_from(num_partitions)