Issue deprecation warnings

[afred]

Background: Solrizer has been absorbed by ActiveFedora. You should use ActiveFedora.index_field_mapper where you used to use Solrizer.

Done when: deprecation warnings are issued when attempting to use Solrizer.

[tpendragon]

@Cam156 We'd like to do this in the maintenance sprint next week (week of 9/17). Are there other tickets we should work on to enable the deprecation of Solrizer? README updates, etc? Do you have a sense (or maybe @afred?) about where the best place to put the deprecation warning would be - IE, on gem install vs calling certain Solrizer methods?

[afred]

I'd say put a deprecation warning on the installation, directly above the module declaration (so it's triggered when you first require 'solrizer', and it might not hurt to put one on Solrizer.solr_name, which I'm guessing is how it is most frequently used.

[afred]

It was my understanding that using the Solrizer gem was slated to become a deprecated practice. If that's not the case, then I agree, don't issue deprecation warnings. But if it is the case that we want to discourage use of the solrizer gem, then where else should we be issuing messages?

[jcoyne]

It's deprecated (as in we discourage its use) in modern versions of Hyrax/HydraHead, but I still use it with my very old Hydra-Head (7.x) applications. I'd prefer not to see deprecation warnings there, because it's perfectly reasonable to use it in an old Hydra-head.

[afred]

Cool. I guess I misunderstood the fate of Solrizer. I assumed we'd soon stop providing support, but I guess that's incorrect?

I'm fine closing this ticket as well as the PR that would close it. But what's then the best way to discourage it's use in Hyrax? For instance, what prompted me to create this ticket in the first place was that our Hyrax app we were using Solrizer.solr_name in our indexers. If that's discouraged, is there a way we can discourage it programatically, so that programmers who may have missed it in the release notes can be made aware in code?