Fix queryDelegatorTotalRewards (#4078)

Return [] instead of null by making the initial
value an empty slice literal opposed to nil.

Closes: #3705

.pending/bugfixes/sdk/3705-Return-instead-of-null-when-querying-delegator-rewards

@@ -0,0 +1 @@
+#3705 Return `[]` instead of `null` when querying delegator rewards.

x/distribution/alias.go

@@ -71,4 +71,21 @@ var (
 	DefaultGenesisState = types.DefaultGenesisState
 	ValidateGenesis     = types.ValidateGenesis
 	InitialFeePool      = types.InitialFeePool
+
+	// Query types
+	QueryParams                      = keeper.QueryParams
+	QueryValidatorOutstandingRewards = keeper.QueryValidatorOutstandingRewards
+	QueryValidatorCommission         = keeper.QueryValidatorCommission
+	QueryValidatorSlashes            = keeper.QueryValidatorSlashes
+	QueryDelegationRewards           = keeper.QueryDelegationRewards
+	QueryDelegatorTotalRewards       = keeper.QueryDelegatorTotalRewards
+	QueryDelegatorValidators         = keeper.QueryDelegatorValidators
+	QueryWithdrawAddr                = keeper.QueryWithdrawAddr
+	QueryCommunityPool               = keeper.QueryCommunityPool
+
+	// Param types
+	ParamCommunityTax        = keeper.ParamCommunityTax
+	ParamBaseProposerReward  = keeper.ParamBaseProposerReward
+	ParamBonusProposerReward = keeper.ParamBonusProposerReward
+	ParamWithdrawAddrEnabled = keeper.ParamWithdrawAddrEnabled
 )

x/distribution/client/common/common.go

@@ -11,26 +11,26 @@ import (
 
 // QueryParams actually queries distribution params.
 func QueryParams(cliCtx context.CLIContext, queryRoute string) (PrettyParams, error) {
-	route := fmt.Sprintf("custom/%s/params/community_tax", queryRoute)
+	route := fmt.Sprintf("custom/%s/params/%s", queryRoute, distr.ParamCommunityTax)
 
 	retCommunityTax, err := cliCtx.QueryWithData(route, []byte{})
 	if err != nil {
 		return PrettyParams{}, err
 	}
 
-	route = fmt.Sprintf("custom/%s/params/base_proposer_reward", queryRoute)
+	route = fmt.Sprintf("custom/%s/params/%s", queryRoute, distr.ParamBaseProposerReward)
 	retBaseProposerReward, err := cliCtx.QueryWithData(route, []byte{})
 	if err != nil {
 		return PrettyParams{}, err
 	}
 
-	route = fmt.Sprintf("custom/%s/params/bonus_proposer_reward", queryRoute)
+	route = fmt.Sprintf("custom/%s/params/%s", queryRoute, distr.ParamBonusProposerReward)
 	retBonusProposerReward, err := cliCtx.QueryWithData(route, []byte{})
 	if err != nil {
 		return PrettyParams{}, err
 	}
 
-	route = fmt.Sprintf("custom/%s/params/withdraw_addr_enabled", queryRoute)
+	route = fmt.Sprintf("custom/%s/params/%s", queryRoute, distr.ParamWithdrawAddrEnabled)
 	retWithdrawAddrEnabled, err := cliCtx.QueryWithData(route, []byte{})
 	if err != nil {
 		return PrettyParams{}, err
@@ -50,7 +50,7 @@ func QueryDelegatorTotalRewards(cliCtx context.CLIContext, cdc *codec.Codec,
 	}
 
 	return cliCtx.QueryWithData(
-		fmt.Sprintf("custom/%s/delegator_total_rewards", queryRoute),
+		fmt.Sprintf("custom/%s/%s", queryRoute, distr.QueryDelegatorTotalRewards),
 		cdc.MustMarshalJSON(distr.NewQueryDelegatorParams(delegatorAddr)),
 	)
 }
@@ -69,7 +69,7 @@ func QueryDelegationRewards(cliCtx context.CLIContext, cdc *codec.Codec,
 	}
 
 	return cliCtx.QueryWithData(
-		fmt.Sprintf("custom/%s/delegation_rewards", queryRoute),
+		fmt.Sprintf("custom/%s/%s", queryRoute, distr.QueryDelegationRewards),
 		cdc.MustMarshalJSON(distr.NewQueryDelegationRewardsParams(delegatorAddr, validatorAddr)),
 	)
 }
@@ -80,7 +80,7 @@ func QueryDelegatorValidators(cliCtx context.CLIContext, cdc *codec.Codec,
 	queryRoute string, delegatorAddr sdk.AccAddress) ([]byte, error) {
 
 	return cliCtx.QueryWithData(
-		fmt.Sprintf("custom/%s/delegator_validators", queryRoute),
+		fmt.Sprintf("custom/%s/%s", queryRoute, distr.QueryDelegatorValidators),
 		cdc.MustMarshalJSON(distr.NewQueryDelegatorParams(delegatorAddr)),
 	)
 }
@@ -90,7 +90,7 @@ func QueryValidatorCommission(cliCtx context.CLIContext, cdc *codec.Codec,
 	queryRoute string, validatorAddr sdk.ValAddress) ([]byte, error) {
 
 	return cliCtx.QueryWithData(
-		fmt.Sprintf("custom/%s/validator_commission", queryRoute),
+		fmt.Sprintf("custom/%s/%s", queryRoute, distr.QueryValidatorCommission),
 		cdc.MustMarshalJSON(distr.NewQueryValidatorCommissionParams(validatorAddr)),
 	)
 }

x/distribution/keeper/querier.go

@@ -241,7 +241,7 @@ func queryDelegatorTotalRewards(ctx sdk.Context, _ []string, req abci.RequestQue
 	// cache-wrap context as to not persist state changes during querying
 	ctx, _ = ctx.CacheContext()
 
-	var totalRewards sdk.DecCoins
+	totalRewards := sdk.DecCoins{}
 
 	k.stakingKeeper.IterateDelegations(
 		ctx, params.DelegatorAddress,