fix null incrementing

miner/miner.go

@@ -188,6 +188,8 @@ func (m *Miner) mine(ctx context.Context) {
 				log.Errorf("failed to submit newly mined block: %s", err)
 			}
 		} else {
+			base.NullRounds++
+
 			// Wait until the next epoch, plus the propagation delay, so a new tipset
 			// has enough time to form.
 			//
@@ -261,7 +263,6 @@ func (m *Miner) mineOne(ctx context.Context, base *MiningBase) (*types.BlockMsg,
 		return nil, xerrors.Errorf("failed to get mining base info: %w", err)
 	}
 	if mbi == nil {
-		base.NullRounds++
 		return nil, nil
 	}
 
@@ -278,7 +279,6 @@ func (m *Miner) mineOne(ctx context.Context, base *MiningBase) (*types.BlockMsg,
 	}
 	if !hasPower {
 		// slashed or just have no power yet
-		base.NullRounds++
 		return nil, nil
 	}
 
@@ -302,7 +302,6 @@ func (m *Miner) mineOne(ctx context.Context, base *MiningBase) (*types.BlockMsg,
 	}
 
 	if winner == nil {
-		base.NullRounds++
 		return nil, nil
 	}