[MM-37898] Exclude bots from initial user store emptiness check (#18139)

* Exclude bots from initial user store emptiness check

* Add test

services/users/users.go

@@ -43,7 +43,7 @@ func (us *UserService) CreateUser(user *model.User, opts UserCreateOptions) (*mo
 
 	// Below is a special case where the first user in the entire
 	// system is granted the system_admin role
-	if ok, err := us.store.IsEmpty(); err != nil {
+	if ok, err := us.store.IsEmpty(true); err != nil {
 		return nil, errors.Wrap(UserStoreIsEmptyError, err.Error())
 	} else if ok {
 		user.Roles = model.SystemAdminRoleId + " " + model.SystemUserRoleId

services/users/users_test.go

@@ -5,6 +5,10 @@ package users
 
 import (
 	"testing"
+
+	"github.com/mattermost/mattermost-server/v6/model"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestIsUsernameTaken(t *testing.T) {
@@ -27,3 +31,59 @@ func TestIsUsernameTaken(t *testing.T) {
 		t.FailNow()
 	}
 }
+
+func TestFirstUserPromoted(t *testing.T) {
+	th := Setup(t)
+	defer th.TearDown()
+
+	user, err := th.service.CreateUser(&model.User{
+		Username: model.NewId(),
+		Password: model.NewId(),
+		Email:    "user@example.com",
+	}, UserCreateOptions{})
+	require.NoError(t, err)
+	require.NotNil(t, user)
+
+	require.Equal(t, model.SystemAdminRoleId+" "+model.SystemUserRoleId, user.Roles)
+
+	user2, err := th.service.CreateUser(&model.User{
+		Username: model.NewId(),
+		Password: model.NewId(),
+		Email:    "user2@example.com",
+	}, UserCreateOptions{})
+	require.NoError(t, err)
+	require.NotNil(t, user2)
+
+	require.Equal(t, model.SystemUserRoleId, user2.Roles)
+
+	th.dbStore.User().PermanentDelete(user.Id)
+
+	b := &model.Bot{
+		UserId:   user2.Id,
+		OwnerId:  model.NewId(),
+		Username: model.NewId(),
+	}
+
+	_, err = th.dbStore.Bot().Save(b)
+	require.NoError(t, err)
+
+	user3, err := th.service.CreateUser(&model.User{
+		Username: model.NewId(),
+		Password: model.NewId(),
+		Email:    "user3@example.com",
+	}, UserCreateOptions{})
+	require.NoError(t, err)
+	require.NotNil(t, user3)
+
+	require.Equal(t, model.SystemAdminRoleId+" "+model.SystemUserRoleId, user3.Roles)
+
+	user4, err := th.service.CreateUser(&model.User{
+		Username: model.NewId(),
+		Password: model.NewId(),
+		Email:    "user4@example.com",
+	}, UserCreateOptions{})
+	require.NoError(t, err)
+	require.NotNil(t, user4)
+
+	require.Equal(t, model.SystemUserRoleId, user4.Roles)
+}