BUG - if a section is deleted the frontend crashes

[Nostrabramus]

Context

I'm using OJS 3.3.0.10

Bug

• I create a section and enable: "an archive of all submissions published in this section".
• I create a new menu item with that section
• I add the new menu item to the primary navigation menu
• I look at the frontend and the new menu item appears and works
• I go back to the backend and delete the newly created section
• I look at the frontend again and the page rendering stops where the primary navigation menu was supposed to be rendered

Expected result

the primary navigation menu should be rendered without the nonexistent menu item and without crashing the rest of the page

Possible Fix

check if the section exists before returning a null element

I'm not sure if the problem belongs to the browseBySection extension rather than the default theme

[ctgraham]

Stack trace suggests this plugin as the likely culprit.

PHP Fatal error:  Uncaught Error: Call to a member function getData() on null in plugins/generic/browseBySection/BrowseBySectionPlugin.inc.php:267
Stack trace:
#0 lib/pkp/classes/plugins/HookRegistry.inc.php(107): BrowseBySectionPlugin->setMenuItemDisplayDetails()
#1 lib/pkp/classes/services/PKPNavigationMenuService.inc.php(362): HookRegistry::call()
#2 lib/pkp/classes/services/PKPNavigationMenuService.inc.php(438): PKP\\Services\\PKPNavigationMenuService->getDisplayStatus()
#3 lib/pkp/classes/services/PKPNavigationMenuService.inc.php(425): PKP\\Services\\PKPNavigationMenuService->loadMenuTreeDisplayState()
#4 lib/pkp/classes/template/PKPTemplateManager.inc.php(2062): PKP\\Services\\PKPNavigationMenuService->getMenuTree()
#5 plugins/generic/browseBySection/BrowseBySectionPlugin.inc.php on line 267

[ctgraham]

Mitigation could be here: https://github.com/pkp/browseBySection/blob/fcb80b608a25dd1b9243e616bf9c068002bbdc46/BrowseBySectionPlugin.inc.php#L267

With:

                        if (!$section) {
                                return false;
                        }

But perhaps the plugin should also hook the section delete to cleanup its data.