Email activities with just a "0" in the body don't save the details on the activity
I'm not sure this is worth fixing because if a person were to do this, the right response from civi should be to teach them a lesson by corrupting their database beyond repair and then displaying a cryptic message, like "Nothing went wrong while saving. It's fine."
- Go to Contacts - New Email.
- Fill out a recipient and subject.
- In the editor, click on the "Source" button.
- Just enter a 0.
- Don't put anything in the plain-text format section.
- Click Save.
- The database will store NULL in civicrm_activity.details.
It's because of the way these conditionals work: https://github.com/civicrm/civicrm-core/blob/1bc5c7abcc6326c8123c636a52a5e4a8378dffbe/CRM/Activity/BAO/Activity.php#L961-L967
Maybe a rainy-day todo.