multiple $bs in items from marc_export can confuse external systems

One way to do it to preserve backwards compatibility would be to have marc_export (and Supercat) add the owning library and circulating library to new, additional subfields while still retaining the two 852 $b.

The tradeoff would be the result permitting fewer items to be embedded in the MARC record before running into the ISO 2709 limit.

Alternatively: add command-=line options to marc_export (easy) and library settings for Supercat output to tune this, though the more options we add, the more that going to the effort of creating item record MARC embedding templates would be desirable.

My pedantic self wants to say 852 $b is repeatable, so the discovery layer needs to just deal with it.

I would be OK with:

1. Just using the circ library from asset.copy and dropping the owning library.
2. Making it optional, via command line, to show one or the other, both if not specified.
3. Making circ library the default and adding an option to add the owning library, or to show owning library instead.

That's in order from most to least preferred change.

We have a use case for going by owning library, not circ lib, so #1 isn't ideal.

My proposal based on your feedback:

- marc_export: add a new switch to provide options for the circ & owning lib handling, with the status quo being preserved if the new switch isn't added.

- Supercat: add library settings or global flags to match, but keep it light-weight. However, thinking about it more, the Supercat bit is optionally, perhaps, as the discovery layer in question (Aspen) is already looking at the additional holdings XML emitted by the marcxml-full option, so the contents of the 852 (for incremental updates) don't matter at present.

A patch adding a switch along the lines I've suggested is available in user/gmcharlt/lp2004587_marc_export_852b / https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/gmcharlt/lp2004587_marc_export_852b

Note that while this branch is on top of the branch for bug 2015484, there's no logical dependency between the two pull requests.

I've done some testing with this branch and it seems to work as described. I tried an export with the various options with items that have different owning and circ libs and things look correct.

<option omitted> works the same as --852b both.
--852b both - shows both, owning_lib first and circ_lib second.
--852b owning_lib - works as described.
--852b circ_lib - works as described.

Here is a signoff branch at
user/stompro/lp2004587_marc_export_852b_signoff

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/stompro/lp2004587_marc_export_852b_signoff

Josh

I have been looking at this one and a couple of other marc_export patches over the past couple of weeks, and this one does what it says on the tin.

I've pushed it to main for future Evergreen releases.

Thanks, Galen and Josh!