Undefined index in mailing report for mailing_modified_date; and room for refactoring
Notice: Undefined property: CRM_Mailing_BAO_Mailing::$mailing_modified_date in CRM_Mailing_BAO_Mailing::report() (line 1821 of /home/developer/buildkit/build/civicrmdev/sites/all/modules/civicrm/CRM/Mailing/BAO/Mailing.php).
Appears on pages like: /civicrm/mailing/report?mid=7&reset=1
This is because the DAO key for the field is 'mailing_modified_date' - but the name is 'modified_date'.
And the way the field values are assigned to the object does not account for this difference.
This is a very minor issue as the modified date doesn't actually get used in the report!
We should probably refactor the query/code to only load the fields we're actually interested in; and get rid of the raw SQL in the file at the same time: https://github.com/civicrm/civicrm-core/blob/f87c35c7308fc6876e1a4fea8ac3ea908d3d9453/CRM/Mailing/BAO/Mailing.php#L1807