update Blacklight to 8.0

[jrochkind]

Will require some messing with our customizations.

In particular, I am aware that the way we customize "constraints" will not work in Blacklight 8. (for our additional "public domain-only" limit, plus our custom editable query constraint)

(I actually now wonder if we need to have all that custom code for the public domain constraint -- what if we just add an ordinary pre-existing facet constraint instead? I am not sure why we didn't!)

Upgrade to Blacklight 8 is necessary to use latest version of view_component gem. At some point something happened in view_component that broke Blacklight which Blacklight had to fix -- I am not sure exactly what version of view_component, but I believe the fix happened only in BL8.

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Status -- holding off, due to challenges

Resolved some problems including applying constraint and other overrides in a way that works with BL8. But we're still having a lot of challenges and blockers.

We have done what preparation we can in master branch still on BL7. And have a draft not-ready branch with where we have been able to get to on BL8 at #2238

Why is it a problem to be stuck on BL 7

We are stuck on the dependent view_component gem version 2.x, so can't get bugfixes and new features from there, and may eventually have problems with Rails compatibility. Because Blacklight 7 isn't compatible with view_component 2.

This is potentially a big problem. Issue asking if it might be possible to backport view_component 3.x compat to BL7 at projectblacklight/blacklight#3052

But we'd also be stuck on Rails 7.0 anyway, when we really want to upgrade to Rails 7.1 when it comes out.

Challenges/reasons to be wary

• It would be nice to be able to selectively load/install just parts of BL JS, and may be necessary in future. It used to be possible. Currently unclear: Should it be possible to selectively import blacklight-frontend modules in Blacklight 8, without importmaps? projectblacklight/blacklight#3050. Fixed at Fix allowing imports of individual source files/modules from blacklight-frontend npm package projectblacklight/blacklight#3128

• It is pretty unclear if blacklight_range_limit is actually working/supported on BL 8 at all. Install on Rails 7/Blacklight 8 projectblacklight/blacklight_range_limit#236

  • However, we HAVE hackily gotten it to work in a blacklight 8 branch... we aren't even sure how.
  • But don't feel good about using a dependency where we are unable to create a "from scratch" blank app, or run tests on master for blacklight_range_limit locally, or even understand how we got it working. Not confident we can maintain it properly in these conditions, or keep it from breaking, or submitting bugfixes, etc.

Current known blockers:

• "More facets" scroll not working properly: "More" facets modal not scrollable on Blacklight 8/Bootstrap 4 projectblacklight/blacklight#3051

  • We might be able to fix this if we update to Bootstrap 5 instead of Bootstrap 4 -- but that's pretty significant work for us. May require a lot of CSS changes, and CSS malfunctions mostly aren't caught by tests, so a lot of QA.

• blacklight_range_limit facet appears even when there are no results -- our "no results" page has a "date" facet in the sidebar, whereas in BL 7 it did not.

  • Have not been able to reproduce in a blank app and file a clean issue -- because we have not been able to get a BL8 app with blacklight_range_limit to work at all! But did file what we could here: Blacklight 8, empty range facet shown even for zero results page projectblacklight/blacklight_range_limit#237
  • Actually, there is a problem specific to blacklight_range_limit, but even if we stopped using that, there is a separate problem where the heading "limit your search" will show up confusingly labelling nothing on the "zero results" page, even though blacklight_range_limit. "Limit your search" header shows even if no facets are available, eg a zero results page projectblacklight/blacklight#3054

[jrochkind]

There are some backports being made to a Blacklight-7 release branch in Blacklight -- if there is a BL release made with these, this is a good step prior to full upgrade to BL8, and would let us do things like update to ViewComponent 3.x

eg

• Release 7.x backports projectblacklight/blacklight#3071