Send to Kindle still fails with E999 when a book has a subtitle

[vannevarmorgan]

What went wrong?

This was reported in #1181 and closed as fixed in 3.3.0. It's not fixed, I still get E999 on
3.3.1.

Any book with a subtitle ends up with two dc:title elements, since addSubtitleToTitle() adds
one for EPUB3. There's already a test for that behaviour
(EpubMetadataWriterTest.epub3_shouldAddSubtitleWithRefinement).

Nothing looks wrong from inside Grimmory. The send succeeds and it logs success, then Amazon
mails the rejection separately.

How can we reproduce it?

Two epubs attached. Same file apart from two lines, both clean under epubcheck 5.2.1.

dc:titleSend To Kindle Repro</dc:title>
<dc:title id="subtitle-0001">A Subtitle</dc:title>
subtitle

Send both to your Kindle address. The first arrives, the second comes back E999.

I also tried versions with only the extra identifiers, only the booklore:* metas, only the
series metadata, and only the subjects/description. Those all arrived fine. Only the extra
dc:title breaks it.

Removed the subtitle dc:title from two real books that had been failing for days and they went
through fine.

kindle-e999-reproducer.zip

What Build of Grimmory are you on?

Stable

Your setup

Grimmory 3.3.1, also saw it on 3.2.4
Docker
Firefox, Safari
Ubuntu 24.04

Screenshots or error messages (optional)

E999 - Send to Kindle Internal Error

Before submitting

• I've searched existing issues and discussions and this hasn't been reported yet
• I've reviewed this report and have completed it as fully as I can

[coderabbitai]

🔗 Related PRs

#473 - fix(kobo): handle missing book when pulling kobo metadata [merged]
#1543 - feat(kobo): add subtitle to KoboBookMetadata [merged]
#1637 - fix(metadata): extract epub titles per spec with regards to ordering [merged]
#2002 - refactor(kobo): implement Grimmory kepub transformation [open]
#2048 - fix(epub): remove refines when referenced elements are removed [merged]

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[imnotjames]

To be fair: The feature is not send-to-kindle. The feature is send to email. We are sending a perfectly valid epub3 as far as I can tell, over email, correctly.

I'll investigate anyway, but this really seems like a limitation of the kindle parsing of epub3.

[imnotjames]

It looks like we can add a title-type of main for the main title and treat that as the main title - then they can properly read it. Given this is valid within epub3 and technically more explicitly correct I will implement it.

However, this just means that Amazon is going against the epub3 spec. Shocking, I know.

Per EPUB3 5.5.3.1.2:

The first dc:title element in document order is the main title of the EPUB publication (i.e., the primary one reading systems present to users).

🤷

[vannevarmorgan]

nice, appreciate the review.
Anything I can help with?