cleanup: Reduce and normalize import path aliasing. (#6975)

The code in the Tendermint repository makes heavy use of import aliasing.
This is made necessary by our extensive reuse of common base package names, and
by repetition of similar names across different subdirectories.

Unfortunately we have not been very consistent about which packages we alias in
various circumstances, and the aliases we use vary. In the spirit of the advice
in the style guide and https://github.com/golang/go/wiki/CodeReviewComments#imports,
his change makes an effort to clean up and normalize import aliasing.

This change makes no API or behavioral changes. It is a pure cleanup intended
o help make the code more readable to developers (including myself) trying to
understand what is being imported where.

Only unexported names have been modified, and the changes were generated and
applied mechanically with gofmt -r and comby, respecting the lexical and
syntactic rules of Go.  Even so, I did not fix every inconsistency. Where the
changes would be too disruptive, I left it alone.

The principles I followed in this cleanup are:

- Remove aliases that restate the package name.
- Remove aliases where the base package name is unambiguous.
- Move overly-terse abbreviations from the import to the usage site.
- Fix lexical issues (remove underscores, remove capitalization).
- Fix import groupings to more closely match the style guide.
- Group blank (side-effecting) imports and ensure they are commented.
- Add aliases to multiple imports with the same base package name.

cmd/tendermint/commands/debug/dump.go

@@ -11,7 +11,7 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
-	cfg "github.com/tendermint/tendermint/config"
+	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/libs/cli"
 	rpchttp "github.com/tendermint/tendermint/rpc/client/http"
 )
@@ -65,9 +65,9 @@ func dumpCmdHandler(_ *cobra.Command, args []string) error {
 	}
 
 	home := viper.GetString(cli.HomeFlag)
-	conf := cfg.DefaultConfig()
+	conf := config.DefaultConfig()
 	conf = conf.SetRoot(home)
-	cfg.EnsureRoot(conf.RootDir)
+	config.EnsureRoot(conf.RootDir)
 
 	dumpDebugData(outDir, conf, rpc)
 
@@ -79,7 +79,7 @@ func dumpCmdHandler(_ *cobra.Command, args []string) error {
 	return nil
 }
 
-func dumpDebugData(outDir string, conf *cfg.Config, rpc *rpchttp.HTTP) {
+func dumpDebugData(outDir string, conf *config.Config, rpc *rpchttp.HTTP) {
 	start := time.Now().UTC()
 
 	tmpDir, err := ioutil.TempDir(outDir, "tendermint_debug_tmp")

cmd/tendermint/commands/debug/kill.go

@@ -14,7 +14,7 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
-	cfg "github.com/tendermint/tendermint/config"
+	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/libs/cli"
 	rpchttp "github.com/tendermint/tendermint/rpc/client/http"
 )
@@ -50,9 +50,9 @@ func killCmdHandler(cmd *cobra.Command, args []string) error {
 	}
 
 	home := viper.GetString(cli.HomeFlag)
-	conf := cfg.DefaultConfig()
+	conf := config.DefaultConfig()
 	conf = conf.SetRoot(home)
-	cfg.EnsureRoot(conf.RootDir)
+	config.EnsureRoot(conf.RootDir)
 
 	// Create a temporary directory which will contain all the state dumps and
 	// relevant files and directories that will be compressed into a file.

cmd/tendermint/commands/debug/util.go

@@ -9,7 +9,7 @@ import (
 	"path"
 	"path/filepath"
 
-	cfg "github.com/tendermint/tendermint/config"
+	"github.com/tendermint/tendermint/config"
 	rpchttp "github.com/tendermint/tendermint/rpc/client/http"
 )
 
@@ -48,7 +48,7 @@ func dumpConsensusState(rpc *rpchttp.HTTP, dir, filename string) error {
 
 // copyWAL copies the Tendermint node's WAL file. It returns an error if the
 // WAL file cannot be read or copied.
-func copyWAL(conf *cfg.Config, dir string) error {
+func copyWAL(conf *config.Config, dir string) error {
 	walPath := conf.Consensus.WalFile()
 	walFile := filepath.Base(walPath)
 

cmd/tendermint/commands/light.go

@@ -11,7 +11,6 @@ import (
 	"time"
 
 	"github.com/spf13/cobra"
-
 	dbm "github.com/tendermint/tm-db"
 
 	"github.com/tendermint/tendermint/libs/log"

cmd/tendermint/commands/reindex_event.go

@@ -6,7 +6,7 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
-	tmdb "github.com/tendermint/tm-db"
+	dbm "github.com/tendermint/tm-db"
 
 	abcitypes "github.com/tendermint/tendermint/abci/types"
 	tmcfg "github.com/tendermint/tendermint/config"
@@ -15,7 +15,7 @@ import (
 	"github.com/tendermint/tendermint/internal/state/indexer"
 	"github.com/tendermint/tendermint/internal/state/indexer/sink/kv"
 	"github.com/tendermint/tendermint/internal/state/indexer/sink/psql"
-	ctypes "github.com/tendermint/tendermint/rpc/coretypes"
+	"github.com/tendermint/tendermint/rpc/coretypes"
 	"github.com/tendermint/tendermint/store"
 	"github.com/tendermint/tendermint/types"
 )
@@ -129,17 +129,17 @@ func loadEventSinks(cfg *tmcfg.Config) ([]indexer.EventSink, error) {
 }
 
 func loadStateAndBlockStore(cfg *tmcfg.Config) (*store.BlockStore, state.Store, error) {
-	dbType := tmdb.BackendType(cfg.DBBackend)
+	dbType := dbm.BackendType(cfg.DBBackend)
 
 	// Get BlockStore
-	blockStoreDB, err := tmdb.NewDB("blockstore", dbType, cfg.DBDir())
+	blockStoreDB, err := dbm.NewDB("blockstore", dbType, cfg.DBDir())
 	if err != nil {
 		return nil, nil, err
 	}
 	blockStore := store.NewBlockStore(blockStoreDB)
 
 	// Get StateStore
-	stateDB, err := tmdb.NewDB("state", dbType, cfg.DBDir())
+	stateDB, err := dbm.NewDB("state", dbType, cfg.DBDir())
 	if err != nil {
 		return nil, nil, err
 	}
@@ -221,14 +221,15 @@ func checkValidHeight(bs state.BlockStore) error {
 	}
 
 	if startHeight < base {
-		return fmt.Errorf("%s (requested start height: %d, base height: %d)", ctypes.ErrHeightNotAvailable, startHeight, base)
+		return fmt.Errorf("%s (requested start height: %d, base height: %d)",
+			coretypes.ErrHeightNotAvailable, startHeight, base)
 	}
 
 	height := bs.Height()
 
 	if startHeight > height {
 		return fmt.Errorf(
-			"%s (requested start height: %d, store height: %d)", ctypes.ErrHeightNotAvailable, startHeight, height)
+			"%s (requested start height: %d, store height: %d)", coretypes.ErrHeightNotAvailable, startHeight, height)
 	}
 
 	if endHeight == 0 || endHeight > height {
@@ -238,13 +239,13 @@ func checkValidHeight(bs state.BlockStore) error {
 
 	if endHeight < base {
 		return fmt.Errorf(
-			"%s (requested end height: %d, base height: %d)", ctypes.ErrHeightNotAvailable, endHeight, base)
+			"%s (requested end height: %d, base height: %d)", coretypes.ErrHeightNotAvailable, endHeight, base)
 	}
 
 	if endHeight < startHeight {
 		return fmt.Errorf(
 			"%s (requested the end height: %d is less than the start height: %d)",
-			ctypes.ErrInvalidRequest, startHeight, endHeight)
+			coretypes.ErrInvalidRequest, startHeight, endHeight)
 	}
 
 	return nil

cmd/tendermint/main.go

@@ -6,9 +6,9 @@ import (
 
 	cmd "github.com/tendermint/tendermint/cmd/tendermint/commands"
 	"github.com/tendermint/tendermint/cmd/tendermint/commands/debug"
-	cfg "github.com/tendermint/tendermint/config"
+	"github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/libs/cli"
-	nm "github.com/tendermint/tendermint/node"
+	"github.com/tendermint/tendermint/node"
 )
 
 func main() {
@@ -42,12 +42,12 @@ func main() {
 	//	* Provide their own DB implementation
 	// can copy this file and use something other than the
 	// node.NewDefault function
-	nodeFunc := nm.NewDefault
+	nodeFunc := node.NewDefault
 
 	// Create & start node
 	rootCmd.AddCommand(cmd.NewRunNodeCmd(nodeFunc))
 
-	cmd := cli.PrepareBaseCmd(rootCmd, "TM", os.ExpandEnv(filepath.Join("$HOME", cfg.DefaultTendermintDir)))
+	cmd := cli.PrepareBaseCmd(rootCmd, "TM", os.ExpandEnv(filepath.Join("$HOME", config.DefaultTendermintDir)))
 	if err := cmd.Execute(); err != nil {
 		panic(err)
 	}