Changes have been made in Git for this ticket:

Fix procmail vacation rule if no dates are set (Gaudenz Steinlin 
<gaudenz@debian.org>, Bug #8982).

http://git.horde.org/diff.php/ingo/docs/CHANGES?rt=horde-git&r1=ac2de5be025256de7a2eec40b1662ed0e9c87699&r2=cda18fe5401fff1daa9b11675c51062fea1dcca0
http://git.horde.org/diff.php/ingo/lib/Script/Procmail/Recipe.php?rt=horde-git&r1=c4232e3d4d98929909c02900d62a188479d4eccd&r2=cda18fe5401fff1daa9b11675c51062fea1dcca0

Changes have been made in CVS for this ticket:

[jan] Fix procmail vacation rule if no dates are set (Gaudenz Steinlin
       <gaudenz@debian.org>, Bug #9134).
http://cvs.horde.org/diff.php/ingo/docs/CHANGES?rt=horde&r1=1.55.2.144&r2=1.55.2.145&ty=u
http://cvs.horde.org/diff.php/ingo/lib/Script/procmail.php?rt=horde&r1=1.46.10.35&r2=1.46.10.36&ty=u

Is anyone working on this bug? IMHO this is a pretty serious issue. I 
can confirm that the patch the original submitter added in the bug 
text works. I have attached the same patch as an attachment in case 
this is more convenient to integrate.

As a first step I added the c flag but I disvocered sometimes a dual 
delivery of mails.
So I decided to block the rule as the date rule version.

I can verify that vacation generates a bad procmail script -- when the 
auto-reply is triggered normal delivery is not completed.

But the fix is much easier. There's just a missing "c" on the rule 
that actually sends the reply; we need procmail to reply to a copy of 
the message so that it continues rather than stopping after the reply 
is sent.

So the code should be:

$this->_action[] = '      | formail -rD 8192 
${VACATION_DIR:-.}/.vacation.' . $address;
$this->_action[] = '      :0 ehc';
$this->_action[] = '      | (formail -rI"Precedence: junk" \\';

Rather than the current:

$this->_action[] = '      | formail -rD 8192 
${VACATION_DIR:-.}/.vacation.' . $address;
$this->_action[] = '      :0 eh';
$this->_action[] = '      | (formail -rI"Precedence: junk" \\';

I noticed that the vacation rule sends a vacation notice but didn't 
deliver the message.
The next message of the same sender is delivered.
This is caused because the last rule with the eh flags checks the 
result of the preceding rule. If the sender is not it the vacation 
file then the result of formail is an error and the last rule is 
executed und the script finish without to deliver the received 
message. So we need a carbon copy flag (c) to deliver the received 
message.
I added this flag to the last rule and discovered a double delivery of 
the message.
Then I used the vacation with a time window an discovered that it works.
Finally I used the time vacation code for the vacation without a time 
frame with removed time check rule.
So I updated the code as follows:

--- horde-orig/ingo/lib/Script/procmail.php       2009-09-16 
14:37:22.000000000 +0200
+++ horde-dev/ingo/lib/Script/procmail.php       2010-04-21 
10:00:29.000000000 +0200
@@ -491,9 +491,9 @@
                      $this->_action[] = '    :0 Whc: 
${VACATION_DIR:-.}/vacation.lock';
                      if ($timed) {
                          $this->_action[] = '    * ? test $DATE -gt 
$START && test $END -gt $DATE';
-                       $this->_action[] = '    {';
-                        $this->_action[] = '      :0 Wh';
                      }
+                    $this->_action[] = '    {';
+                    $this->_action[] = '      :0 Wh';
                      $this->_action[] = '      * ^TO_' . $address;
                      $this->_action[] = '      * !^X-Loop: ' . $address;
                      $this->_action[] = '      * !^X-Spam-Flag: YES';
@@ -524,9 +524,7 @@
                      $reason = addcslashes($reason, "\\\n\r\t\"`");
                      $this->_action[] = '       ' . 
$this->_params['echo'] . ' -e "' . $reason . '" \\';
                      $this->_action[] = '      ) | $SENDMAIL -f' . 
$address . ' -oi -t';
-                    if ($timed) {
-                        $this->_action[] = '    }';
-                    }
+                    $this->_action[] = '    }';
                      $this->_action[] = '  }';
                  }
              }

Kind regards,

Rene Plattner