Running this in a GitPod instance and trying to add the identifier paaski to a book and it seems like it doesn't save the identifier at all? It also seems to not save other identifiers, so probably not an issue with this PR(?), but I have no clue how to debug. The logs seem to suggest that the data (with identifier) gets POST’ed alright, but then… it just isn’t saved/stored?

web-1           | 0.06 (1): 200 POST /openlibrary.org/save_many {'query': '[{"title": "PAA SKI OVER GR\\u00d8NLAND", "authors": [{"author": {"key": "/authors/OL5A"}}], "k
ey": "/works/OL1W", "type": {"key": "/type/work"}, "latest_revision": 1, "revision": 1, "created": {"type": "/type/datetime", "value": "2024-11-11T13:59:43.093028"}, "las
t_modified": {"type": "/type/datetime", "value": "2024-11-11T13:59:43.093028"}, "description": null, "subjects": null, "subject_people": null, "subject_places": null, "su
bject_times": null, "subtitle": null, "excerpts": null, "links": null}, {"works": [{"key": "/works/OL1W"}], "title": "PAA SKI OVER GR\\u00d8NLAND", "publishers": ["Runebe
rg"], "publish_date": "2010", "key": "/books/OL5M", "type": {"key": "/type/edition"}, "latest_revision": 1, "revision": 1, "created": {"type": "/type/datetime", "value": 
"2024-11-11T13:59:43.093028"}, "last_modified": {"type": "/type/datetime", "value": "2024-11-11T13:59:43.093028"}, "identifiers": {"project_runeberg": ["paaski"]}, "class
ifications": {}, "weight": null, "table_of_contents": null, "contributors": [], "providers": [], "title_prefix": null, "subtitle": null, "publish_places": null, "copyrigh
t_date": null, "edition_name": null, "series": null, "by_statement": null, "languages": null, "translation_of": null, "translated_from": null, "description": null, "notes
": null, "other_titles": null, "physical_format": null, "number_of_pages": null, "pagination": null, "first_sentence": null, "roles": []}]', 'comment': '', 'action': 'edi
t-book', 'data': '{}'}

Edit: I now see you were having the issue with books not authors. Let me take a look.
@Freso
Gitpod from master it working fine to add identifiers.
Gitpod from your branch is also working fine to add identifiers including Runeberg

Perhaps try stopping and starting the docker compose again?

Adding runeburg IDs to a book worked (showing on the book page)
But the book page also shows
/openlibrary/openlibrary/templates/book_providers/runeberg_download_options.html: error in processing template: AttributeError: 'str' object has no attribute 'zip' (falling back to default template)

Which seems to be related to

However, I don't know enough about your templating engine to fix it. Maybe @cdrini can chime in

I’ve been able to test this now on GitPod, and it seems to work fine. My question in #9984 (comment) is still unanswered, though.

Also, #9982 hasn’t been reviewed (let alone merged) in the almost 3 weeks since these were opened; so just a heads-up that this also contains the commit from that PR (since this PR depends on the other PR, as mentioned in the OP). I was planning to undraft this when #9982 had been merged (so I could rebase on master with the #9982 commit), but going ahead and undrafting now. #9982 has been merged and this PR has been rebased on master.