[Dovecot] sieve: deleteheader sometimes fails [bug]

[Daniel Piddock]

Hi,

We're using Dovecot 2.1.16 with Pigeonhole 0.3.4. Mail is delivered by
exim4 to the dovecot LDA.

Sometimes users are unable to delete headers. I've narrowed the problem
down to preceding the deleteheader command with a query against the body.

A simple example:
"""
require ["body", "editheader", "fileinto"];
if body :contains "!TEST!" {
  fileinto "INBOX.Trash";
  stop;
}
deleteheader "Subject";
addheader "Subject" "Testing";
"""

Putting the "deleteheader" above the "if body" causes it to be deleted
correctly. Although I've used Subject in this example it happens for
other headers.

Cheers,
Dan