review comments

program-test/tests/stake.rs

@@ -73,7 +73,7 @@ async fn test_stake_redelegation_pending_activation(merge_flag: PendingStakeActi
     // 3. create 2nd vote account
     let vote_address2 = setup_vote(&mut context).await;
 
-    // 3.1 relegate 1st stake account to 2nd stake account.
+    // 3.1 relegate stake account to 2nd vote account, which creates 2nd stake account
     let stake_keypair2 = Keypair::new();
     let stake_address2 = stake_keypair2.pubkey();
     let transaction = Transaction::new_signed_with_payer(

programs/stake/src/stake_state.rs

@@ -639,18 +639,17 @@ fn deactivate_stake(
     stake_flags: &mut StakeFlags,
     epoch: Epoch,
 ) -> Result<(), InstructionError> {
-    let stake_history = invoke_context.get_sysvar_cache().get_stake_history()?;
-
     if invoke_context
         .feature_set
         .is_active(&feature_set::stake_redelegate_instruction::id())
     {
         if stake_flags.contains(StakeFlags::MUST_FULLY_ACTIVATE_BEFORE_DEACTIVATION_IS_PERMITTED) {
+            let stake_history = invoke_context.get_sysvar_cache().get_stake_history()?;
             // when MUST_FULLY_ACTIVATE_BEFORE_DEACTIVATION_IS_PERMITTED flag is set on stake_flags,
             // deactivation is only permitted when the stake delegation activating amount is zero.
             let status = stake.delegation.stake_activating_and_deactivating(
                 epoch,
-                Some(&stake_history),
+                Some(stake_history.as_ref()),
                 new_warmup_cooldown_rate_epoch(invoke_context),
             );
             if status.activating != 0 {