Fix validator set bug (MystenLabs#3594)

crates/sui-framework/sources/governance/sui_system.move

@@ -100,7 +100,7 @@ module sui::sui_system {
         ctx: &mut TxContext,
     ) {
         assert!(
-            validator_set::total_validator_candidate_count(&self.validators) < self.parameters.max_validator_candidate_count,
+            validator_set::next_epoch_validator_count(&self.validators) < self.parameters.max_validator_candidate_count,
             0
         );
         let stake_amount = coin::value(&stake);
@@ -226,7 +226,7 @@ module sui::sui_system {
         delegation::undelegate(delegation, self.epoch, ctx)
     }
 
-    // Switch delegation from the current validator to a new one. 
+    // Switch delegation from the current validator to a new one.
     public entry fun request_switch_delegation(
         self: &mut SuiSystemState,
         delegation: &mut Delegation,
@@ -316,17 +316,17 @@ module sui::sui_system {
         self.epoch
     }
 
-    /// Returns the amount of stake delegated to `validator_addr`. 
+    /// Returns the amount of stake delegated to `validator_addr`.
     /// Aborts if `validator_addr` is not an active validator.
     public fun validator_delegate_amount(self: &SuiSystemState, validator_addr: address): u64 {
         validator_set::validator_delegate_amount(&self.validators, validator_addr)
-    } 
+    }
 
-    /// Returns the amount of delegators who have delegated to `validator_addr`. 
+    /// Returns the amount of delegators who have delegated to `validator_addr`.
     /// Aborts if `validator_addr` is not an active validator.
     public fun validator_delegator_count(self: &SuiSystemState, validator_addr: address): u64 {
         validator_set::validator_delegator_count(&self.validators, validator_addr)
-    } 
+    }
 
     #[test_only]
     public fun set_epoch_for_testing(self: &mut SuiSystemState, epoch_num: u64) {

crates/sui-framework/sources/governance/validator_set.move

@@ -62,11 +62,9 @@ module sui::validator_set {
         validators
     }
 
-    /// Get the total number of candidates that might become validators in the next epoch.
-    public(friend) fun total_validator_candidate_count(self: &ValidatorSet): u64 {
-        vector::length(&self.active_validators)
-            + vector::length(&self.pending_validators)
-            - vector::length(&self.pending_removals)
+    /// Get the total number of validators in the next epoch.
+    public(friend) fun next_epoch_validator_count(self: &ValidatorSet): u64 {
+        vector::length(&self.next_epoch_validators)
     }
 
     /// Called by `SuiSystem`, add a new validator to `pending_validators`, which will be
@@ -448,6 +446,15 @@ module sui::validator_set {
             vector::push_back(&mut result, *metadata);
             active_count = active_count - 1;
         };
+        let i = 0;
+        let pending_count = vector::length(&self.pending_validators);
+        while (i < pending_count) {
+            let metadata = validator::metadata(
+                vector::borrow(&self.pending_validators, i),
+            );
+            vector::push_back(&mut result, *metadata);
+            i = i + 1;
+        };
         result
     }
 

crates/sui-framework/tests/validator_set_tests.move

@@ -26,7 +26,7 @@ module sui::validator_set_tests {
 
         // Create a validator set with only the first validator in it.
         let validator_set = validator_set::new(vector[validator1]);
-        assert!(validator_set::total_validator_candidate_count(&validator_set) == 1, 0);
+        assert!(validator_set::next_epoch_validator_count(&validator_set) == 1, 0);
         assert!(validator_set::total_validator_stake(&validator_set) == 100, 0);
 
         // Add the other 3 validators one by one.
@@ -35,7 +35,7 @@ module sui::validator_set_tests {
             validator2,
         );
         // Adding validator during the epoch should not affect stake and quorum threshold.
-        assert!(validator_set::total_validator_candidate_count(&validator_set) == 2, 0);
+        assert!(validator_set::next_epoch_validator_count(&validator_set) == 2, 0);
         assert!(validator_set::total_validator_stake(&validator_set) == 100, 0);
 
         validator_set::request_add_validator(
@@ -83,15 +83,15 @@ module sui::validator_set_tests {
             let ctx1 = test_scenario::ctx(&mut scenario);
             validator_set::advance_epoch(&mut validator_set, &mut reward, ctx1);
             // The total stake and quorum should reflect 4 validators.
-            assert!(validator_set::total_validator_candidate_count(&validator_set) == 4, 0);
+            assert!(validator_set::next_epoch_validator_count(&validator_set) == 4, 0);
             assert!(validator_set::total_validator_stake(&validator_set) == 1000, 0);
 
             validator_set::request_remove_validator(
                 &mut validator_set,
                 ctx1,
             );
             // Total validator candidate count changes, but total stake remains during epoch.
-            assert!(validator_set::total_validator_candidate_count(&validator_set) == 3, 0);
+            assert!(validator_set::next_epoch_validator_count(&validator_set) == 3, 0);
             assert!(validator_set::total_validator_stake(&validator_set) == 1000, 0);
             validator_set::advance_epoch(&mut validator_set, &mut reward, ctx1);
             // Validator1 is gone.