cmd: deprecate --testnet, use named networks instead (#20852)

* cmd/utils: make goerli the default testnet

* cmd/geth: explicitly rename testnet to ropsten

* core: explicitly rename testnet to ropsten

* params: explicitly rename testnet to ropsten

* cmd: explicitly rename testnet to ropsten

* miner: explicitly rename testnet to ropsten

* mobile: allow for returning the goerli spec

* tests: explicitly rename testnet to ropsten

* docs: update readme to reflect changes to the default testnet

* mobile: allow for configuring goerli and rinkeby nodes

* cmd/geth: revert --testnet back to ropsten and mark as legacy

* cmd/util: mark --testnet flag as deprecated

* docs: update readme to properly reflect the 3 testnets

* cmd/utils: add an explicit deprecation warning on startup

* cmd/utils: swap goerli and ropsten in usage

* cmd/geth: swap goerli and ropsten in usage

* cmd/geth: if running a known preset, log it for convenience

* docs: improve readme on usage of ropsten's testnet datadir

* cmd/utils: check if legacy `testnet` datadir exists for ropsten

* cmd/geth: check for legacy testnet path in console command

* cmd/geth: use switch statement for complex conditions in main

* cmd/geth: move known preset log statement to the very top

* cmd/utils: create new ropsten configurations in the ropsten datadir

* cmd/utils: makedatadir should check for existing testnet dir

* cmd/geth: add legacy testnet flag to the copy db command

* cmd/geth: add legacy testnet flag to the inspect command

cmd/geth/chaincmd.go

@@ -156,8 +156,10 @@ The export-preimages command export hash preimages to an RLP encoded stream`,
 			utils.CacheFlag,
 			utils.SyncModeFlag,
 			utils.FakePoWFlag,
-			utils.TestnetFlag,
+			utils.RopstenFlag,
 			utils.RinkebyFlag,
+			utils.GoerliFlag,
+			utils.LegacyTestnetFlag,
 		},
 		Category: "BLOCKCHAIN COMMANDS",
 		Description: `
@@ -203,9 +205,10 @@ Use "ethereum dump 0" to dump the genesis block.`,
 			utils.DataDirFlag,
 			utils.AncientFlag,
 			utils.CacheFlag,
-			utils.TestnetFlag,
+			utils.RopstenFlag,
 			utils.RinkebyFlag,
 			utils.GoerliFlag,
+			utils.LegacyTestnetFlag,
 			utils.SyncModeFlag,
 		},
 		Category: "BLOCKCHAIN COMMANDS",

cmd/geth/consolecmd.go

@@ -123,10 +123,19 @@ func remoteConsole(ctx *cli.Context) error {
 			path = ctx.GlobalString(utils.DataDirFlag.Name)
 		}
 		if path != "" {
-			if ctx.GlobalBool(utils.TestnetFlag.Name) {
-				path = filepath.Join(path, "testnet")
+			if ctx.GlobalBool(utils.LegacyTestnetFlag.Name) || ctx.GlobalBool(utils.RopstenFlag.Name) {
+				// Maintain compatibility with older Geth configurations storing the
+				// Ropsten database in `testnet` instead of `ropsten`.
+				legacyPath := filepath.Join(path, "testnet")
+				if _, err := os.Stat(legacyPath); !os.IsNotExist(err) {
+					path = legacyPath
+				} else {
+					path = filepath.Join(path, "ropsten")
+				}
 			} else if ctx.GlobalBool(utils.RinkebyFlag.Name) {
 				path = filepath.Join(path, "rinkeby")
+			} else if ctx.GlobalBool(utils.GoerliFlag.Name) {
+				path = filepath.Join(path, "goerli")
 			}
 		}
 		endpoint = fmt.Sprintf("%s/geth.ipc", path)

cmd/geth/main.go

@@ -138,7 +138,8 @@ var (
 		utils.DNSDiscoveryFlag,
 		utils.DeveloperFlag,
 		utils.DeveloperPeriodFlag,
-		utils.TestnetFlag,
+		utils.LegacyTestnetFlag,
+		utils.RopstenFlag,
 		utils.RinkebyFlag,
 		utils.GoerliFlag,
 		utils.VMEnableDebugFlag,
@@ -258,10 +259,32 @@ func main() {
 // prepare manipulates memory cache allowance and setups metric system.
 // This function should be called before launching devp2p stack.
 func prepare(ctx *cli.Context) {
+	// If we're running a known preset, log it for convenience.
+	switch {
+	case ctx.GlobalIsSet(utils.LegacyTestnetFlag.Name):
+		log.Info("Starting Geth on Ropsten testnet...")
+		log.Warn("The --testnet flag is ambiguous! Please specify one of --goerli, --rinkeby, or --ropsten.")
+		log.Warn("The generic --testnet flag is deprecated and will be removed in the future!")
+
+	case ctx.GlobalIsSet(utils.RopstenFlag.Name):
+		log.Info("Starting Geth on Ropsten testnet...")
+
+	case ctx.GlobalIsSet(utils.RinkebyFlag.Name):
+		log.Info("Starting Geth on Rinkeby testnet...")
+
+	case ctx.GlobalIsSet(utils.GoerliFlag.Name):
+		log.Info("Starting Geth on Görli testnet...")
+
+	case ctx.GlobalIsSet(utils.DeveloperFlag.Name):
+		log.Info("Starting Geth in ephemeral dev mode...")
+
+	case !ctx.GlobalIsSet(utils.NetworkIdFlag.Name):
+		log.Info("Starting Geth on Ethereum mainnet...")
+	}
 	// If we're a full node on mainnet without --cache specified, bump default cache allowance
 	if ctx.GlobalString(utils.SyncModeFlag.Name) != "light" && !ctx.GlobalIsSet(utils.CacheFlag.Name) && !ctx.GlobalIsSet(utils.NetworkIdFlag.Name) {
 		// Make sure we're not on any supported preconfigured testnet either
-		if !ctx.GlobalIsSet(utils.TestnetFlag.Name) && !ctx.GlobalIsSet(utils.RinkebyFlag.Name) && !ctx.GlobalIsSet(utils.GoerliFlag.Name) && !ctx.GlobalIsSet(utils.DeveloperFlag.Name) {
+		if !ctx.GlobalIsSet(utils.LegacyTestnetFlag.Name) && !ctx.GlobalIsSet(utils.RopstenFlag.Name) && !ctx.GlobalIsSet(utils.RinkebyFlag.Name) && !ctx.GlobalIsSet(utils.GoerliFlag.Name) && !ctx.GlobalIsSet(utils.DeveloperFlag.Name) {
 			// Nope, we're really on mainnet. Bump that cache up!
 			log.Info("Bumping default cache on mainnet", "provided", ctx.GlobalInt(utils.CacheFlag.Name), "updated", 4096)
 			ctx.GlobalSet(utils.CacheFlag.Name, strconv.Itoa(4096))

cmd/geth/usage.go

@@ -72,9 +72,9 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.NoUSBFlag,
 			utils.SmartCardDaemonPathFlag,
 			utils.NetworkIdFlag,
-			utils.TestnetFlag,
-			utils.RinkebyFlag,
 			utils.GoerliFlag,
+			utils.RinkebyFlag,
+			utils.RopstenFlag,
 			utils.SyncModeFlag,
 			utils.ExitWhenSyncedFlag,
 			utils.GCModeFlag,
@@ -245,6 +245,7 @@ var AppHelpFlagGroups = []flagGroup{
 	{
 		Name: "DEPRECATED",
 		Flags: []cli.Flag{
+			utils.LegacyTestnetFlag,
 			utils.LightLegacyServFlag,
 			utils.LightLegacyPeersFlag,
 			utils.MinerLegacyThreadsFlag,