From 6be78713b74898e7109085ee5d88488e70aad372 Mon Sep 17 00:00:00 2001
From: Eric Warehime <eric.warehime@gmail.com>
Date: Tue, 19 Dec 2023 17:09:08 -0800
Subject: [PATCH] fix(baseapp): Reset GasMeter before deliverTX v0.47.x
 backport (#18826)

---
 CHANGELOG.md            |  1 +
 baseapp/abci.go         |  4 ++++
 baseapp/baseapp_test.go | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9195332f0f9a..5db27ee1fff6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -44,6 +44,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Bug Fixes
 
+* (baseapp) [#18609](https://github.com/cosmos/cosmos-sdk/issues/18609) Fixed accounting in the block gas meter after BeginBlock and before DeliverTx, ensuring transaction processing always starts with the expected zeroed out block gas meter.
 * (server) [#18537](https://github.com/cosmos/cosmos-sdk/pull/18537) Fix panic when defining minimum gas config as `100stake;100uatom`. Use a `,` delimiter instead of `;`. Fixes the server config getter to use the correct delimiter.
 * (client/tx) [#18472](https://github.com/cosmos/cosmos-sdk/pull/18472) Utilizes the correct Pubkey when simulating a transaction.
 
diff --git a/baseapp/abci.go b/baseapp/abci.go
index 32a6d8683227..08dbe8d367b9 100644
--- a/baseapp/abci.go
+++ b/baseapp/abci.go
@@ -206,6 +206,10 @@ func (app *BaseApp) BeginBlock(req abci.RequestBeginBlock) (res abci.ResponseBeg
 		}
 	}
 
+	// Reset the gas meter so that the AnteHandlers aren't required to
+	gasMeter = app.getBlockGasMeter(app.deliverState.ctx)
+	app.deliverState.ctx = app.deliverState.ctx.WithBlockGasMeter(gasMeter)
+
 	return res
 }
 
diff --git a/baseapp/baseapp_test.go b/baseapp/baseapp_test.go
index 84614a9a6f5f..c278d7cf85e7 100644
--- a/baseapp/baseapp_test.go
+++ b/baseapp/baseapp_test.go
@@ -158,6 +158,41 @@ func NewBaseAppSuiteWithSnapshots(t *testing.T, cfg SnapshotsConfig, opts ...fun
 	return suite
 }
 
+func TestAnteHandlerGasMeter(t *testing.T) {
+	// run BeginBlock and assert that the gas meter passed into the first Txn's AnteHandlers is zeroed out
+	anteOpt := func(bapp *baseapp.BaseApp) {
+		bapp.SetAnteHandler(func(ctx sdk.Context, tx sdk.Tx, simulate bool) (newCtx sdk.Context, err error) {
+			gasMeter := ctx.BlockGasMeter()
+			require.NotNil(t, gasMeter)
+			require.Equal(t, sdk.Gas(0), gasMeter.GasConsumed())
+			return ctx, nil
+		})
+	}
+	// set the beginBlocker to use some gas
+	beginBlockerOpt := func(bapp *baseapp.BaseApp) {
+		bapp.SetBeginBlocker(func(ctx sdk.Context, req abci.RequestBeginBlock) abci.ResponseBeginBlock {
+			ctx.BlockGasMeter().ConsumeGas(1, "beginBlocker gas consumption")
+			return abci.ResponseBeginBlock{}
+		})
+	}
+
+	suite := NewBaseAppSuite(t, anteOpt, beginBlockerOpt)
+
+	_ = suite.baseApp.InitChain(abci.RequestInitChain{
+		ConsensusParams: &tmproto.ConsensusParams{},
+	})
+
+	// Run BeginBlock to consume some gas
+	header := tmproto.Header{Height: 1}
+	suite.baseApp.BeginBlock(abci.RequestBeginBlock{Header: header})
+
+	// Run our first Tx (make sure the AnteHandler doesn't see gas consumed in BeginBlock
+	tx := newTxCounter(t, suite.txConfig, 0, 0)
+	txBytes, err := suite.txConfig.TxEncoder()(tx)
+	require.NoError(t, err)
+	suite.baseApp.DeliverTx(abci.RequestDeliverTx{Tx: txBytes})
+}
+
 func TestLoadVersion(t *testing.T) {
 	logger := defaultLogger()
 	pruningOpt := baseapp.SetPruning(pruningtypes.NewPruningOptions(pruningtypes.PruningNothing))