Prefer fmt.Errorf(s) to errors.New(fmt.Sprintf(s))

pkg/config/plugin.go

@@ -71,7 +71,7 @@ func (pluginConfig *Plugin) GetMigrationsPaths() ([]string, error) {
 		if ok {
 			conflictingPath := paths[transformer.MigrationRank]
 			if conflictingPath != cleanPath {
-				return nil, errors.New(fmt.Sprintf("transformer %s has the same migration rank (%d) as another transformer", name, transformer.MigrationRank))
+				return nil, fmt.Errorf("transformer %s has the same migration rank (%d) as another transformer", name, transformer.MigrationRank)
 			}
 		}
 		paths[transformer.MigrationRank] = cleanPath

pkg/datastore/postgres/errors.go

@@ -1,7 +1,6 @@
 package postgres
 
 import (
-	"errors"
 	"fmt"
 )
 
@@ -34,5 +33,5 @@ func ErrUnableToSetNode(setErr error) error {
 }
 
 func formatError(msg, err string) error {
-	return errors.New(fmt.Sprintf("%s: %s", msg, err))
+	return fmt.Errorf("%s: %s", msg, err)
 }

pkg/plugin/builder/builder.go

@@ -17,7 +17,6 @@
 package builder
 
 import (
-	"errors"
 	"fmt"
 	"os"
 	"os/exec"
@@ -68,7 +67,7 @@ func (b *builder) BuildPlugin() error {
 	// Build the .go file into a .so plugin
 	execErr := exec.Command("go", "build", "-buildmode=plugin", "-o", soFile, b.goFile).Run()
 	if execErr != nil {
-		return errors.New(fmt.Sprintf("unable to build .so file: %s", execErr.Error()))
+		return fmt.Errorf("unable to build .so file: %s", execErr.Error())
 	}
 	return nil
 }
@@ -94,7 +93,7 @@ func (b *builder) setupBuildEnv() error {
 
 		copyErr := helpers.CopyDir(src, dst, "vendor")
 		if copyErr != nil {
-			return errors.New(fmt.Sprintf("unable to copy transformer dependency from %s to %s: %v", src, dst, copyErr))
+			return fmt.Errorf("unable to copy transformer dependency from %s to %s: %v", src, dst, copyErr)
 		}
 
 		// Have to clear out the copied over vendor lib or plugin won't build (see issue above)

pkg/plugin/manager/manager.go

@@ -18,7 +18,6 @@ package manager
 
 import (
 	"database/sql"
-	"errors"
 	"fmt"
 	"github.com/lib/pq"
 	"github.com/pressly/goose"
@@ -59,7 +58,7 @@ func (m *manager) setDB() error {
 	}
 	dbConnector, err := pq.NewConnector(pgStr)
 	if err != nil {
-		return errors.New(fmt.Sprintf("can't connect to db: %s", err.Error()))
+		return fmt.Errorf("can't connect to db: %s", err.Error())
 	}
 	m.db = sql.OpenDB(dbConnector)
 	return nil
@@ -99,12 +98,12 @@ func (m *manager) setupMigrationEnv() error {
 	removeErr := os.RemoveAll(m.tmpMigDir)
 	if removeErr != nil {
 		removeErrString := "unable to remove file found at %s where tmp directory needs to be written: %s"
-		return errors.New(fmt.Sprintf(removeErrString, m.tmpMigDir, removeErr.Error()))
+		return fmt.Errorf(removeErrString, m.tmpMigDir, removeErr.Error())
 	}
 	mkdirErr := os.Mkdir(m.tmpMigDir, os.FileMode(os.ModePerm))
 	if mkdirErr != nil {
 		mkdirErrString := "unable to create temporary migration directory %s: %s"
-		return errors.New(fmt.Sprintf(mkdirErrString, m.tmpMigDir, mkdirErr.Error()))
+		return fmt.Errorf(mkdirErrString, m.tmpMigDir, mkdirErr.Error())
 	}
 
 	return nil
@@ -145,18 +144,18 @@ func (m *manager) fixAndRun(path string) error {
 	if m.db == nil {
 		setErr := m.setDB()
 		if setErr != nil {
-			return errors.New(fmt.Sprintf("could not open db: %s", setErr.Error()))
+			return fmt.Errorf("could not open db: %s", setErr.Error())
 		}
 	}
 	// Fix the migrations
 	fixErr := goose.Fix(m.tmpMigDir)
 	if fixErr != nil {
-		return errors.New(fmt.Sprintf("version fixing for plugin migrations at %s failed: %s", path, fixErr.Error()))
+		return fmt.Errorf("version fixing for plugin migrations at %s failed: %s", path, fixErr.Error())
 	}
 	// Run the copied migrations with goose
 	upErr := goose.Up(m.db, m.tmpMigDir)
 	if upErr != nil {
-		return errors.New(fmt.Sprintf("db migrations for plugin transformers at %s failed: %s", path, upErr.Error()))
+		return fmt.Errorf("db migrations for plugin transformers at %s failed: %s", path, upErr.Error())
 	}
 	return nil
 }

pkg/plugin/writer/writer.go

@@ -17,7 +17,6 @@
 package writer
 
 import (
-	"errors"
 	"fmt"
 
 	. "github.com/dave/jennifer/jen"
@@ -89,7 +88,7 @@ func (w *writer) WritePlugin() error {
 	// Write code to destination file
 	err = f.Save(goFile)
 	if err != nil {
-		return errors.New(fmt.Sprintf("failed to save generated .go file: %s\r\n%s", goFile, err.Error()))
+		return fmt.Errorf("failed to save generated .go file: %s\r\n%s", goFile, err.Error())
 	}
 	return nil
 }
@@ -107,7 +106,7 @@ func (w *writer) collectTransformers() (map[config.TransformerType][]Code, error
 		case config.EthContract:
 			code[config.EthContract] = append(code[config.EthContract], Qual(path, "ContractTransformerInitializer"))
 		default:
-			return nil, errors.New(fmt.Sprintf("invalid transformer type %s", transformer.Type))
+			return nil, fmt.Errorf("invalid transformer type %s", transformer.Type)
 		}
 	}