From eba7cb01aecfec6b65902075337e7bf2a517541b Mon Sep 17 00:00:00 2001
From: likhita-809 <78951027+likhita-809@users.noreply.github.com>
Date: Mon, 18 Oct 2021 15:03:20 +0530
Subject: [PATCH] supply cosmos/cosmos-sdk#10393

---
 CHANGELOG.md                 | 2 ++
 x/bank/keeper/keeper.go      | 8 ++++++++
 x/bank/keeper/keeper_test.go | 1 +
 3 files changed, 11 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 360b4301b161..dc4575a060c7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -40,6 +40,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ### Improvements
 
 * [\#10486](https://github.com/cosmos/cosmos-sdk/pull/10486) store/cachekv's `Store.Write` conservatively looks up keys, but also uses the [map clearing idiom](https://bencher.orijtech.com/perfclinic/mapclearing/) to reduce the RAM usage, CPU time usage, and garbage collection pressure from clearing maps, instead of allocating new maps.
+* [\#10393](https://github.com/cosmos/cosmos-sdk/pull/10393) Add `HasSupply` method to bank keeper to ensure that input denom actually exists on chain.
+
 ### Bug Fixes
 
 * [\#10414](https://github.com/cosmos/cosmos-sdk/pull/10414) Use `sdk.GetConfig().GetFullBIP44Path()` instead `sdk.FullFundraiserPath` to generate key
diff --git a/x/bank/keeper/keeper.go b/x/bank/keeper/keeper.go
index cc8ded240136..482c002870bd 100644
--- a/x/bank/keeper/keeper.go
+++ b/x/bank/keeper/keeper.go
@@ -25,6 +25,7 @@ type Keeper interface {
 	ExportGenesis(sdk.Context) *types.GenesisState
 
 	GetSupply(ctx sdk.Context, denom string) sdk.Coin
+	HasSupply(ctx sdk.Context, denom string) bool
 	GetPaginatedTotalSupply(ctx sdk.Context, pagination *query.PageRequest) (sdk.Coins, *query.PageResponse, error)
 	IterateTotalSupply(ctx sdk.Context, cb func(sdk.Coin) bool)
 	GetDenomMetaData(ctx sdk.Context, denom string) (types.Metadata, bool)
@@ -214,6 +215,13 @@ func (k BaseKeeper) GetSupply(ctx sdk.Context, denom string) sdk.Coin {
 	}
 }
 
+// HasSupply checks if the supply coin exists in store.
+func (k BaseKeeper) HasSupply(ctx sdk.Context, denom string) bool {
+	store := ctx.KVStore(k.storeKey)
+	supplyStore := prefix.NewStore(store, types.SupplyKey)
+	return supplyStore.Has([]byte(denom))
+}
+
 // GetDenomMetaData retrieves the denomination metadata. returns the metadata and true if the denom exists,
 // false otherwise.
 func (k BaseKeeper) GetDenomMetaData(ctx sdk.Context, denom string) (types.Metadata, bool) {
diff --git a/x/bank/keeper/keeper_test.go b/x/bank/keeper/keeper_test.go
index f9074f423e92..93f355260bf8 100644
--- a/x/bank/keeper/keeper_test.go
+++ b/x/bank/keeper/keeper_test.go
@@ -1113,6 +1113,7 @@ func (suite *IntegrationTestSuite) TestBalanceTrackingEvents() {
 	}
 
 	// check balance and supply tracking
+	suite.Require().True(suite.app.BankKeeper.HasSupply(suite.ctx, "utxo"))
 	savedSupply := suite.app.BankKeeper.GetSupply(suite.ctx, "utxo")
 	utxoSupply := savedSupply
 	suite.Require().Equal(utxoSupply.Amount, supply.AmountOf("utxo"))