[Sieve] Understand Sieve processing

[h8h]

Hi,

I have the following configuration:
> cat > /etc/dovecot/conf.d/99-local-sieve.conf << EOF;
> plugin {
>  sieve_before = /etc/dovecot/sieve-spam.sieve
>  sieve_before2 = /mail/sieve/global_before
>  sieve_after = /mail/sieve/global_after
>  sieve = /mail/sieve/%d/%n.sieve
>  sieve_dir = /mail/sieve/%d/%n
> }
> EOF

> cat /etc/dovecot/sieve-spam.sieve
> require ["regex", "fileinto", "imap4flags"];
>
> if allof (header :regex "X-Spam-Status" "^Yes") {
>  fileinto "Spam";
> }

(I removed the keyword "stop;" to proceed rule processing, which does 
not work)


Now as a user (/mail/sieve/%d/%n.sieve) I want to create my own "Spam" rule:
> require ["regex","reject"];
> # rule:[SPAM]
> if allof (header :regex "x-spam-status" "^Yes")
> {
>        reject text:
> This E-Mail is SPAM.
> .
> ;
> }



I activate the traces and see the following if the e-mail is SPAM:

>      ## Started executing script 'sieve-spam'
>   3: jump if result is false
>   3:   not jumping
>   4: fileinto action
>   4:   store message in mailbox `Spam'
>      ## Finished executing script 'sieve-spam'


If the e-mail is not SPAM:
>      ## Started executing script 'sieve-spam'
>   3: jump if result is false
>   3:   jumping to line 4
>      ## Finished executing script 'sieve-spam'
>
>
>      ## Started executing script 'roundcube'
>   3: jump if result is false
>   3:   jumping to line 10
>      ## Finished executing script 'roundcube'

So my sieve gets only executed if the e-mail is not SPAM. Thats a bit odd.

Could you explain how the sieve processing work and how I can solve this 
problem?

 dovecot --version
2.2.33.2 (d6601f4ec)
on Ubuntu 18.04 LTS

Best regards
Homy