[Bugfix] duplicating flag registration (#7853)

cmd/gateway-main.go

@@ -48,7 +48,7 @@ var (
 
 // RegisterGatewayCommand registers a new command for gateway.
 func RegisterGatewayCommand(cmd cli.Command) error {
-	cmd.Flags = append(append(cmd.Flags, append(cmd.Flags, ServerFlags...)...), GlobalFlags...)
+	cmd.Flags = append(append(cmd.Flags, ServerFlags...), GlobalFlags...)
 	gatewayCmd.Subcommands = append(gatewayCmd.Subcommands, cmd)
 	return nil
 }

cmd/gateway-main_test.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 
@@ -34,6 +35,36 @@ func TestRegisterGatewayCommand(t *testing.T) {
 	}
 }
 
+// Test running a registered gateway command with a flag
+func TestRunRegisteredGatewayCommand(t *testing.T) {
+	var err error
+
+	flagName := "test-flag"
+	flagValue := "foo"
+
+	cmd := cli.Command{
+		Name: "test-run-with-flag",
+		Flags: []cli.Flag{
+			cli.StringFlag{Name: flagName},
+		},
+		Action: func(ctx *cli.Context) {
+			if actual := ctx.String(flagName); actual != flagValue {
+				t.Errorf("value of %s expects %s, but got %s", flagName, flagValue, actual)
+			}
+		},
+	}
+
+	err = RegisterGatewayCommand(cmd)
+	if err != nil {
+		t.Errorf("RegisterGatewayCommand got unexpected error: %s", err)
+	}
+
+	if err = newApp("minio").Run(
+		[]string{"minio", "gateway", cmd.Name, fmt.Sprintf("--%s", flagName), flagValue}); err != nil {
+		t.Errorf("running registered gateway command got unexpected error: %s", err)
+	}
+}
+
 // Test parseGatewayEndpoint
 func TestParseGatewayEndpoint(t *testing.T) {
 	testCases := []struct {

docs/gateway/gcs.md

@@ -19,7 +19,7 @@ MinIO GCS Gateway allows you to access Google Cloud Storage (GCS) with Amazon S3
 
 **Note:** For alternate ways to set up *Application Default Credentials*, see [Setting Up Authentication for Server to Server Production Applications](https://developers.google.com/identity/protocols/application-default-credentials).
 
-### 1.1 Run MinIO GCS Gateway Using Docker
+### 1.2 Run MinIO GCS Gateway Using Docker
 ```sh
 docker run -p 9000:9000 --name gcs-s3 \
  -v /path/to/credentials.json:/credentials.json \
@@ -29,7 +29,7 @@ docker run -p 9000:9000 --name gcs-s3 \
  minio/minio gateway gcs yourprojectid
 ```
 
-### 1.2 Run MinIO GCS Gateway Using the MinIO Binary
+### 1.3 Run MinIO GCS Gateway Using the MinIO Binary
 
 ```sh
 export GOOGLE_APPLICATION_CREDENTIALS=/path/to/credentials.json