fix: use correct config key for db_backend

CHANGELOG.md

@@ -58,6 +58,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Bug Fixes
 
+* (server) [#17181](https://github.com/cosmos/cosmos-sdk/pull/17181) Fix `db_backend` lookup fallback from `config.toml`.
 * (runtime) [#17284](https://github.com/cosmos/cosmos-sdk/pull/17284) Properly allow to combine depinject-enabled modules and non-depinject-enabled modules in app v2.
 * (baseapp) [#17251](https://github.com/cosmos/cosmos-sdk/pull/17251) VerifyVoteExtensions and ExtendVote initialize their own contexts/states, allowing VerifyVoteExtensions being called without ExtendVote.
 * (x/auth) [#17209](https://github.com/cosmos/cosmos-sdk/pull/17209) Internal error on AccountInfo when account's public key is not set.

server/config/toml.go

@@ -83,8 +83,7 @@ iavl-disable-fastnode = {{ .BaseConfig.IAVLDisableFastNode }}
 
 # AppDBBackend defines the database backend type to use for the application and snapshots DBs.
 # An empty string indicates that a fallback will be used.
-# First fallback is the deprecated compile-time types.DBBackend value.
-# Second fallback (if the types.DBBackend also isn't set), is the db-backend value set in CometBFT's config.toml.
+# The fallback is the db_backend value set in CometBFT's config.toml.
 app-db-backend = "{{ .BaseConfig.AppDBBackend }}"
 
 ###############################################################################

server/util.go

@@ -403,7 +403,7 @@ func ListenForQuitSignals(g *errgroup.Group, block bool, cancelFn context.Cancel
 func GetAppDBBackend(opts types.AppOptions) dbm.BackendType {
 	rv := cast.ToString(opts.Get("app-db-backend"))
 	if len(rv) == 0 {
-		rv = cast.ToString(opts.Get("db-backend"))
+		rv = cast.ToString(opts.Get("db_backend"))
 	}
 
 	// Cosmos SDK has migrated to cosmos-db which does not support all the backends which tm-db supported

server/util_test.go

@@ -11,7 +11,9 @@ import (
 	"testing"
 
 	cmtcfg "github.com/cometbft/cometbft/config"
+	db "github.com/cosmos/cosmos-db"
 	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
 	"github.com/stretchr/testify/require"
 
 	"github.com/cosmos/cosmos-sdk/client"
@@ -37,6 +39,15 @@ func preRunETestImpl(cmd *cobra.Command, args []string) error {
 	return errCanceledInPreRun
 }
 
+func TestGetAppDBBackend(t *testing.T) {
+	v := viper.New()
+	require.Equal(t, server.GetAppDBBackend(v), db.GoLevelDBBackend)
+	v.Set("db_backend", "dbtype1") // value from CometBFT config
+	require.Equal(t, server.GetAppDBBackend(v), db.BackendType("dbtype1"))
+	v.Set("app-db-backend", "dbtype2") // value from app.toml
+	require.Equal(t, server.GetAppDBBackend(v), db.BackendType("dbtype2"))
+}
+
 func TestInterceptConfigsPreRunHandlerCreatesConfigFilesWhenMissing(t *testing.T) {
 	tempDir := t.TempDir()
 	cmd := server.StartCmd(nil)

tools/confix/data/v0.47-app.toml

@@ -72,8 +72,7 @@ iavl-lazy-loading = false
 
 # AppDBBackend defines the database backend type to use for the application and snapshots DBs.
 # An empty string indicates that a fallback will be used.
-# First fallback is the deprecated compile-time types.DBBackend value.
-# Second fallback (if the types.DBBackend also isn't set), is the db-backend value set in Tendermint's config.toml.
+# The fallback is the db_backend value set in Tendermint's config.toml.
 app-db-backend = ""
 
 ###############################################################################
@@ -107,8 +106,7 @@ prometheus-retention-time = 0
 #
 # Example:
 # [["chain_id", "cosmoshub-1"]]
-global-labels = [
-]
+global-labels = []
 
 ###############################################################################
 ###                           API Configuration                             ###
@@ -236,7 +234,7 @@ streamers = []
 
 [streamers]
 [streamers.file]
-keys = ["*", ]
+keys = ["*"]
 write_dir = ""
 prefix = ""
 
@@ -268,4 +266,4 @@ max-txs = "5000"
 query_gas_limit = 300000
 # This is the number of wasm vm instances we keep cached in memory for speed-up
 # Warning: this is currently unstable and may lead to crashes, best to keep for 0 unless testing locally
-lru_size = 0
+lru_size = 0

tools/confix/data/v0.50-app.toml

@@ -72,8 +72,7 @@ iavl-disable-fastnode = false
 
 # AppDBBackend defines the database backend type to use for the application and snapshots DBs.
 # An empty string indicates that a fallback will be used.
-# First fallback is the deprecated compile-time types.DBBackend value.
-# Second fallback (if the types.DBBackend also isn't set), is the db-backend value set in CometBFT's config.toml.
+# The fallback is the db_backend value set in CometBFT's config.toml.
 app-db-backend = ""
 
 ###############################################################################
@@ -107,8 +106,7 @@ prometheus-retention-time = 0
 #
 # Example:
 # [["chain_id", "cosmoshub-1"]]
-global-labels = [
-]
+global-labels = []
 
 ###############################################################################
 ###                           API Configuration                             ###