Retrieve all the versions of a PDF when saved incrementally

[3051360]

I've observed that PyMuPDF provides functionality to determine the number of versions present in a document.

Currently, I'm utilizing pdfresurrect, a C tool/library designed to "extract older 'hidden' versions of a PDF from the current PDF."

While my larger application is built using PyMuPDF, I have to call the compiled C code through Python for version retrieval, which is not an ideal way of building applications.

I propose that enhancing the capability to retrieve all PDF version files directly within PyMuPDF would be beneficial.

[cipri-tom]

Here's how I do it:

        pattern = re.compile(b'[^t]xref.*?EOF', flags=re.M+re.S)

        # `inc_nb` means the number of incremental update contained in the binary
        matches = list(pattern.finditer(doc.data))
        inc_nb = len(matches)
        if not inc_nb > 1:
            return result

        # here we loop to separate each incremental update in
        # the binary to retrieve each version of the file
        # We don't take into account the current version
        for sub in matches[:-1]:
            stream = doc.data[:sub.span()[1]] # binary code of a version
            if not stream:
                continue
            previous = Doc(stream).as_fitz() # is one of the previous version of the file

[JorjMcKie]

This feature would have to be implemented by our base library MuPDF to make any sense.
Currently, you can find out the number of versions of a PDF: doc.version_count only.

Please talk to the MuPDF colleagues on e.g. their Dicscord channel about options they may see.