MM-21343: Recognize multi-line slash commands without requiring trailing space after trigger word (#13646)

* change how we are parsing the args.command

* change comment

* atttempt to write unit test

* remove quotes

* use unicode.IsSpace

* MM-21343 fix panic

* use table

* test cases

* bad request, add test for missing '/'

* mispelled err

* Update app/command.go

Co-Authored-By: Jesse Hallam <jesse.hallam@gmail.com>

* Update app/command.go

Co-Authored-By: Jesse Hallam <jesse.hallam@gmail.com>

* use a map

* use subtest and add test case of empty command

* go fmt

* do not use t.fatal

* Update app/command.go

Co-Authored-By: Bot from GolangCI <42910462+golangcibot@users.noreply.github.com>

* fix missing unicode import

Co-authored-by: wiggin77 <wiggin77@warpmail.net>
Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>
Co-authored-by: mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Bot from GolangCI <42910462+golangcibot@users.noreply.github.com>

app/command.go

@@ -10,6 +10,7 @@ import (
 	"net/url"
 	"strings"
 	"sync"
+	"unicode"
 
 	goi18n "github.com/mattermost/go-i18n/i18n"
 	"github.com/mattermost/mattermost-server/v5/mlog"
@@ -159,10 +160,20 @@ func (a *App) ListAllCommands(teamId string, T goi18n.TranslateFunc) ([]*model.C
 
 // @openTracingParams args
 func (a *App) ExecuteCommand(args *model.CommandArgs) (*model.CommandResponse, *model.AppError) {
-	parts := strings.Split(args.Command, " ")
-	trigger := parts[0][1:]
+	trigger := ""
+	message := ""
+	index := strings.IndexFunc(args.Command, unicode.IsSpace)
+	if index != -1 {
+		trigger = args.Command[:index]
+		message = args.Command[index+1:]
+	} else {
+		trigger = args.Command
+	}
 	trigger = strings.ToLower(trigger)
-	message := strings.Join(parts[1:], " ")
+	if !strings.HasPrefix(trigger, "/") {
+		return nil, model.NewAppError("command", "api.command.execute_command.format.app_error", map[string]interface{}{"Trigger": trigger}, "", http.StatusBadRequest)
+	}
+	trigger = strings.TrimPrefix(trigger, "/")
 
 	clientTriggerId, triggerId, appErr := model.GenerateTriggerId(args.UserId, a.AsymmetricSigningKey())
 	if appErr != nil {

app/command_test.go

@@ -75,6 +75,49 @@ func TestCreateCommandPost(t *testing.T) {
 	require.Equal(t, err.Id, "api.context.invalid_param.app_error")
 }
 
+func TestExecuteCommand(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	t.Run("valid tests with different whitespace characters", func(t *testing.T) {
+		TestCases := map[string]string{
+			"/code happy path":             "    happy path",
+			"/code\nnewline path":          "    newline path",
+			"/code\n/nDouble newline path": "    /nDouble newline path",
+			"/code  double space":          "     double space",
+			"/code\ttab":                   "    tab",
+		}
+
+		for TestCase, result := range TestCases {
+			args := &model.CommandArgs{
+				Command: TestCase,
+				T:       func(s string, args ...interface{}) string { return s },
+			}
+			resp, _ := th.App.ExecuteCommand(args)
+
+			assert.Equal(t, resp.Text, result)
+		}
+	})
+
+	t.Run("missing slash character", func(t *testing.T) {
+		argsMissingSlashCharacter := &model.CommandArgs{
+			Command: "missing leading slash character",
+			T:       func(s string, args ...interface{}) string { return s },
+		}
+		_, err := th.App.ExecuteCommand(argsMissingSlashCharacter)
+		require.Equal(t, "api.command.execute_command.format.app_error", err.Id)
+	})
+
+	t.Run("empty", func(t *testing.T) {
+		argsMissingSlashCharacter := &model.CommandArgs{
+			Command: "",
+			T:       func(s string, args ...interface{}) string { return s },
+		}
+		_, err := th.App.ExecuteCommand(argsMissingSlashCharacter)
+		require.Equal(t, "api.command.execute_command.format.app_error", err.Id)
+	})
+}
+
 func TestHandleCommandResponsePost(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()

i18n/en.json

@@ -499,6 +499,10 @@
     "id": "api.command.execute_command.failed_resp.app_error",
     "translation": "Command with a trigger of '{{.Trigger}}' returned response {{.Status}}."
   },
+  {
+    "id": "api.command.execute_command.format.app_error",
+    "translation": "Command trigger word is missing the leading slash character"
+  },
   {
     "id": "api.command.execute_command.not_found.app_error",
     "translation": "Command with a trigger of '{{.Trigger}}' not found. To send a message beginning with \"/\", try adding an empty space at the beginning of the message."