[R4R] Require moniker on gaiad init

PENDING.md

@@ -34,6 +34,7 @@ IMPROVEMENTS
   * [\#2749](https://github.com/cosmos/cosmos-sdk/pull/2749) Add --chain-id flag to gaiad testnet
 
 * Gaia
+  * Require moniker to be provided on `gaiad init`.
 
 * SDK
  - [x/mock/simulation] [\#2720] major cleanup, introduction of helper objects, reorganization

cmd/gaia/init/init.go

@@ -51,25 +51,32 @@ func InitCmd(ctx *server.Context, cdc *codec.Codec, appInit server.AppInit) *cob
 		RunE: func(_ *cobra.Command, _ []string) error {
 			config := ctx.Config
 			config.SetRoot(viper.GetString(cli.HomeFlag))
+
 			chainID := viper.GetString(client.FlagChainID)
 			if chainID == "" {
 				chainID = fmt.Sprintf("test-chain-%v", common.RandStr(6))
 			}
+
 			nodeID, _, err := InitializeNodeValidatorFiles(config)
 			if err != nil {
 				return err
 			}
 
-			if viper.GetString(flagMoniker) != "" {
-				config.Moniker = viper.GetString(flagMoniker)
+			moniker := viper.GetString(flagMoniker)
+			if moniker == "" {
+				return fmt.Errorf("required flag \"%s\" has not been set", flagMoniker)
 			}
 
+			config.Moniker = moniker
+
 			var appState json.RawMessage
 			genFile := config.GenesisFile()
+
 			if appState, err = initializeEmptyGenesis(cdc, genFile, chainID,
 				viper.GetBool(flagOverwrite)); err != nil {
 				return err
 			}
+
 			if err = ExportGenesisFile(genFile, chainID, nil, appState); err != nil {
 				return err
 			}
@@ -91,5 +98,6 @@ func InitCmd(ctx *server.Context, cdc *codec.Codec, appInit server.AppInit) *cob
 	cmd.Flags().BoolP(flagOverwrite, "o", false, "overwrite the genesis.json file")
 	cmd.Flags().String(client.FlagChainID, "", "genesis file chain-id, if left blank will be randomly created")
 	cmd.Flags().String(flagMoniker, "", "set the validator's moniker")
+
 	return cmd
 }