From 2fc4b8a15b4057270fc64a02c7e42aa092f4e221 Mon Sep 17 00:00:00 2001
From: William Banfield <wbanfield@gmail.com>
Date: Wed, 17 Aug 2022 10:51:49 -0400
Subject: [PATCH] add deprecation warnings

---
 cmd/tendermint/commands/root.go |  4 ++++
 config/config.go                | 33 +++++++++++++++++++++++++--------
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/cmd/tendermint/commands/root.go b/cmd/tendermint/commands/root.go
index 46c9ac7c7..e4061bc28 100644
--- a/cmd/tendermint/commands/root.go
+++ b/cmd/tendermint/commands/root.go
@@ -53,6 +53,10 @@ func ParseConfig(cmd *cobra.Command) (*cfg.Config, error) {
 	if err := conf.ValidateBasic(); err != nil {
 		return nil, fmt.Errorf("error in config file: %v", err)
 	}
+	err = conf.CheckDeprecated()
+	if err != nil {
+		logger.Info("deprecated usage found in configuration file", "error", err)
+	}
 	return conf, nil
 }
 
diff --git a/config/config.go b/config/config.go
index 497f80c67..f6bc1dc87 100644
--- a/config/config.go
+++ b/config/config.go
@@ -68,14 +68,17 @@ type Config struct {
 	BaseConfig `mapstructure:",squash"`
 
 	// Options for services
-	RPC             *RPCConfig             `mapstructure:"rpc"`
-	P2P             *P2PConfig             `mapstructure:"p2p"`
-	Mempool         *MempoolConfig         `mapstructure:"mempool"`
-	StateSync       *StateSyncConfig       `mapstructure:"statesync"`
-	BlockSync       *BlockSyncConfig       `mapstructure:"blocksync"`
-	Consensus       *ConsensusConfig       `mapstructure:"consensus"`
-	TxIndex         *TxIndexConfig         `mapstructure:"tx_index"`
-	Instrumentation *InstrumentationConfig `mapstructure:"instrumentation"`
+	RPC       *RPCConfig       `mapstructure:"rpc"`
+	P2P       *P2PConfig       `mapstructure:"p2p"`
+	Mempool   *MempoolConfig   `mapstructure:"mempool"`
+	StateSync *StateSyncConfig `mapstructure:"statesync"`
+	BlockSync *BlockSyncConfig `mapstructure:"blocksync"`
+	//TODO(williambanfield): remove this field once v0.37 is released.
+	// https://github.com/tendermint/tendermint/issues/9279
+	DeprecatedFastSyncConfig map[interface{}]interface{} `mapstructure:"fastsync"`
+	Consensus                *ConsensusConfig            `mapstructure:"consensus"`
+	TxIndex                  *TxIndexConfig              `mapstructure:"tx_index"`
+	Instrumentation          *InstrumentationConfig      `mapstructure:"instrumentation"`
 }
 
 // DefaultConfig returns a default configuration for a Tendermint node
@@ -148,6 +151,16 @@ func (cfg *Config) ValidateBasic() error {
 	return nil
 }
 
+func (cfg *Config) CheckDeprecated() error {
+	if cfg.DeprecatedFastSyncConfig != nil {
+		return errors.New("[fastsync] table detected. This section has been renamed to [blocksync]. The values in this deprecated section will be disregarded.")
+	}
+	if cfg.BaseConfig.DeprecatedFastSyncMode != nil {
+		return errors.New("fast_sync key detected. This key has been renamed to block_sync. The value of this deprecated key will be disregarded.")
+	}
+	return nil
+}
+
 //-----------------------------------------------------------------------------
 // BaseConfig
 
@@ -172,6 +185,10 @@ type BaseConfig struct { //nolint: maligned
 	// and verifying their commits
 	BlockSyncMode bool `mapstructure:"block_sync"`
 
+	//TODO(williambanfield): remove this field once v0.37 is released.
+	// https://github.com/tendermint/tendermint/issues/9279
+	DeprecatedFastSyncMode interface{} `mapstructure:"fast_sync"`
+
 	// Database backend: goleveldb | cleveldb | boltdb | rocksdb
 	// * goleveldb (github.com/syndtr/goleveldb - most popular implementation)
 	//   - pure go