import: inventory presence detection false-negative (ISBN redirects)

[drzraf]

When importing, for each book a XHR is sent:
/api/items?action=by-user-and-entities&uris=isbn:XXX

with XXX being the ISBN. The response determine whether the book is already inside the inventory and can be accompanied with shelves, visibility, ... JSON fields.

But ISBN can have redirects.
Is seems that this case cause an confusion in the import screen: The warning about "Book already exist in the inventory" is missing (what may lead a user into mistakenly importing twice a given book) if /api/items was referencing an ISBN alias.

For example: "isbn:2701106117 is a redirect of isbn:9782701106113
Calling /api/items with the former won't return anything (assuming the book was never imported), while using the later will adequately show its ID.

NB: Exporting ISBN aliases/redirects as part of CSV/JSON (or any other mean) would be highly desirable so the present problem could be worked around by omitting "aliasesed" ISBN in the export batch.