Trims whitespace from command arguments in RootCmd (#24218)

- Prevents commands from receiving potential whitespace characters
- Adds a new root test case ensuring various whitespace characters are removed

Co-authored-by: Nathan Geist <ngeist@spiria.com>

server/cmd/mmctl/commands/root.go

@@ -73,6 +73,9 @@ var RootCmd = &cobra.Command{
 	Long:              `Mattermost offers workplace messaging across web, PC and phones with archiving, search and integration with your existing systems. Documentation available at https://docs.mattermost.com`,
 	DisableAutoGenTag: true,
 	PersistentPreRun: func(cmd *cobra.Command, args []string) {
+		for i, arg := range args {
+			args[i] = strings.TrimSpace(arg)
+		}
 		format := viper.GetString("format")
 		if viper.GetBool("disable-pager") {
 			printer.OverrideEnablePager(false)

server/cmd/mmctl/commands/root_test.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package commands
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"github.com/spf13/cobra"
+)
+
+func executeRawCommand(root *cobra.Command, args string) (c *cobra.Command, output string, err error) {
+
+	actual := new(bytes.Buffer)
+	RootCmd.SetOut(actual)
+	RootCmd.SetErr(actual)
+	RootCmd.SetArgs(strings.Split(args, " "))
+	c, err = RootCmd.ExecuteC()
+	return c, actual.String(), err
+}
+
+func (s *MmctlUnitTestSuite) TestArgumentsHaveWhitespaceTrimmed() {
+
+	arguments := []string{"value_1", "value_2"}
+	lineEndings := []string{"\n", "\r", "\r\n"}
+	prettyNames := []string{"-n", "-r", "-r-n"}
+	commandCalled := false
+
+	for i, lineEnding := range lineEndings {
+		testName := fmt.Sprintf("Commands have their arguments stripped of whitespace[%s]", prettyNames[i])
+		s.Run(testName, func() {
+			commandCalled = false
+			commandFunction := func(command *cobra.Command, args []string) {
+				commandCalled = true
+				s.Equal(arguments, args, "Expected arguments to have their whitespace trimmed")
+
+			}
+			mockCommand := &cobra.Command{Use: "test", Run: commandFunction}
+			commandString := strings.Join([]string{"test", " ", arguments[0], lineEnding, " ", arguments[1], lineEnding}, "")
+			RootCmd.AddCommand(mockCommand)
+			executeRawCommand(RootCmd, commandString)
+			s.Require().True(commandCalled, "Expected mock command to be called")
+		})
+	}
+
+}