[ilovejedd]

Hmm, looking further into this issue, there appears to be two possible causes:

1.) Caching: If I change files while Calibre is shut down, the Quality Check plugin doesn't catch any of the changes but sometimes it does if I make changes while Calibre is running.

2.) Possible use of a mapped legacy function to get the "db" size.

/src/calibre/db/legacy.py -> I believe format_metadata uses os.stat which would give the same file size as os.path.getsize

    def sizeof_format(self, index, fmt, index_is_id=False):
        book_id = index if index_is_id else self.id(index)
        return self.new_api.format_metadata(book_id, fmt).get('size', None)

/src/calibre/library/database.py

    def sizeof_format(self, index, format, index_is_id=False):
        ''' Return size of C{format} for book C{index} in bytes'''
        id = index if index_is_id else self.id(index)
        format = format.upper()
        return self.conn.get('SELECT uncompressed_size FROM data WHERE data.book=? AND data.format=?', (id, format), all=False)

Quality Check/check_fix.py

    for fmt in formats.split(','):
        db_size = db.sizeof_format(book_id, fmt, index_is_id=True)
        book_path = db.format_abspath(book_id, fmt, index_is_id=True)
        if not book_path:
            self.log.error('Unable to find path to book id:', book_id, db.title(book_id, index_is_id=True))
            continue
        if os.path.exists(book_path):
            actual_size = os.path.getsize(book_path)
            if actual_size != db_size:

That's pretty much the extent of my practically non-existent Python reading skills.

Fixing the code so sizeof_format gets information from database instead of os.stat or to prevent caching is way beyond my skill set. I'm fairly adept at cut-and-paste though, so I managed to add a nuclear option Force repair book sizes. Per the option name, this will forcibly update the sizes for all formats regardless if it's been changed or not so use with care. I only use it with Search scope - Selected book(s).