debian/changelog prepared?

Hello,

It seems that in current implementation, when looking for the AUTOPPA_VERSION() substitution, all files whose name don't end with '.autoppa' are processed and added to prepared_files set even when no substitution was performed. In addition to this, files that have been prepared aren't included in the merge to the main branch since user is interested in keeping the original files. However, debian/changelog file, which probably should be included in the merge, is not because is considered to be a prepared file as explained before.

Is this a bug or is there any reason for this?

Best regards,
    Javier