[Dovecot] Plugin issue with update from 2.0.19 to 2.1.17

[Reinaldo Matukuma]

Hello. Probably only Timo can help-me with this.

I have a self-made plugin based on the zlib plugin that i use to cryptograph the messages at inbox.

As a side-effect of the cryptography, my plugin changes the size of the message, but until 2.0.19 this works well with dovecot index and the W/S flags.

But now, i'm going to upgrade to 2.1.17 and now i have these messages on log at my test ambiance:

Oct 15 20:19:25 test dovecot: imap(reinaldo at exemplo.com.br): Error: Cached message size smaller than expected (367 < 529)
Oct 15 20:19:25 test dovecot: imap(reinaldo at exemplo.com.br): Error: Maildir filename has wrong S value, renamed the file from /storage/test/messages/exemplo.com.br/reinaldo/Maildir/.Sent/cur/1381879158.M634385P5208.test,S=367,W=378:2,S to /storage/test/messages/exemplo.com.br/reinaldo/Maildir/.Sent/cur/1381879158.M634385P5208.test,S=529:2,S
Oct 15 20:19:25 test dovecot: imap(reinaldo at exemplo.com.br): Error: Corrupted index cache file /storage/test/messages/exemplo.com.br/reinaldo/Maildir/.Sent/dovecot.index.cache: Broken physical size for mail UID 6

I understood with these messages that the dovecot is arguing to get the real size of the file now, overriding the return of size from my crypto plugin. But i don't understood if this is a consequence from the changes to correct the index issue (the dovecot.index.cache issue).

So... I want know if the correct way to fix this would be change my plugin to return the real size of the file (that will be larger than the effective message that the plugin returne after the de-cryptography) or if i need use some new  function to the plugin replace the expected size based on the real size of the message, not of the file.

Thanks

Reinaldo