AZBackgroundMediaFormatter Null Reference on Orphaned Media

[tadean]

Problem/Motivation

In cases where AZBackgroundMediaFormatter is used for media, a php error occurs if the file associated with the media has been deleted.

Describe the bug

AZBackgroundMediaFormatter does not check if its media entity's file actually exists before attempting to make use of it. This leads to crashes on rendering. This can also lead to problems with CAS and Cron breaking since content is sometimes rendered internally during those processes.

To Reproduce

• Delete a file entity that is in use by media that is employed as background media
• Visit the content that contains the background media paragraph

Proposed resolution

AZBackgroundMediaFormatter should check to determine the file of its media actually exists before using it.

Expected behavior

Background media should display blank content if the associated file has somehow disappeared.