feat(cmd): made error messaging closer to coreutils

cmd/del.go

@@ -22,8 +22,8 @@ THE SOFTWARE.
 package cmd
 
 import (
+	"errors"
 	"fmt"
-	"os"
 	"strings"
 
 	"github.com/dgraph-io/badger/v4"
@@ -32,11 +32,12 @@ import (
 
 // delCmd represents the set command
 var delCmd = &cobra.Command{
-	Use:     "del KEY[@DB]",
-	Short:   "Delete a key. Optionally specify a db.",
-	Aliases: []string{"delete", "rm", "remove"},
-	Args:    cobra.ExactArgs(1),
-	RunE:    del,
+	Use:          "del KEY[@DB]",
+	Short:        "Delete a key. Optionally specify a db.",
+	Aliases:      []string{"delete", "rm", "remove"},
+	Args:         cobra.ExactArgs(1),
+	RunE:         del,
+	SilenceUsage: true,
 }
 
 func del(cmd *cobra.Command, args []string) error {
@@ -47,6 +48,14 @@ func del(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	exists, err := keyExists(store, args[0])
+	if err != nil {
+		return fmt.Errorf("cannot remove '%s': %v", args[0], err)
+	}
+	if !exists {
+		return fmt.Errorf("cannot remove '%s': No such key", args[0])
+	}
+
 	targetKey, err := formatKeyForPrompt(store, args[0])
 	if err != nil {
 		return err
@@ -54,13 +63,12 @@ func del(cmd *cobra.Command, args []string) error {
 
 	if !force {
 		var confirm string
-		message := fmt.Sprintf("Are you sure you want to delete %q? (y/n)", targetKey)
+		message := fmt.Sprintf("remove %q: are you sure? (y/n)", targetKey)
 		fmt.Println(message)
 		if _, err := fmt.Scanln(&confirm); err != nil {
-			return err
+			return fmt.Errorf("cannot remove '%s': %v", args[0], err)
 		}
 		if strings.ToLower(confirm) != "y" {
-			fmt.Fprintf(os.Stderr, "Did not delete %q\n", targetKey)
 			return nil
 		}
 	}
@@ -70,7 +78,10 @@ func del(cmd *cobra.Command, args []string) error {
 		readonly: false,
 		sync:     false,
 		transact: func(tx *badger.Txn, k []byte) error {
-			return tx.Delete(k)
+			if err := tx.Delete(k); errors.Is(err, badger.ErrKeyNotFound) {
+				return nil
+			}
+			return fmt.Errorf("cannot remove '%s': %v", args[0], err)
 		},
 	}
 
@@ -82,6 +93,27 @@ func init() {
 	rootCmd.AddCommand(delCmd)
 }
 
+func keyExists(store *Store, arg string) (bool, error) {
+	var notFound bool
+	trans := TransactionArgs{
+		key:      arg,
+		readonly: true,
+		sync:     false,
+		transact: func(tx *badger.Txn, k []byte) error {
+			if _, err := tx.Get(k); errors.Is(err, badger.ErrKeyNotFound) {
+				notFound = true
+				return nil
+			} else {
+				return err
+			}
+		},
+	}
+	if err := store.Transaction(trans); err != nil {
+		return false, err
+	}
+	return !notFound, nil
+}
+
 func formatKeyForPrompt(store *Store, arg string) (string, error) {
 	_, db, err := store.parse(arg, true)
 	if err != nil {