AO3-7294 Maintenance task to reset bookmark-only tags

[Snoopynha]

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Issue

https://otwarchive.atlassian.net/browse/AO3-7294

Purpose

This PR addresses the accumulation of "bookmark-only" tags in wrangler bins. Sometimes, tags that are only used on bookmarks (and have zero works) get assigned a specific type (like Character or Relationship) or get attached to a Fandom. This clutters the wrangling interface with tags that shouldn't be wrangled yet.

Changes implemented:

1. New Rake Task (tags:reset_bookmark_only):

• Identifies tags that are non-canonical, non-synonymous, and have zero works (taggings_count_cache: 0).
• Checks if these tags have been assigned a type other than 'Tag' (Unsorted) OR if they have parent associations (common_taggings).
• Resets the type to 'Tag' (Unsorted) and removes all parent associations.

2. Scheduled Maintenance:

• Added the task to config/schedule.rb to run quarterly, ensuring the bins stay clean automatically over time.

Technical Notes:

• Performance: Uses find_each (batch size 1000) to avoid memory spikes when processing large numbers of tags.
• Database Efficiency: Uses delete_all for associations and update_columns for the tag itself. This intentionally bypasses ActiveRecord callbacks to prevent triggering expensive Elasticsearch/Redis re-indexing for every single tag reset during bulk maintenance.
• Testing: Added a comprehensive spec file (spec/lib/tasks/reset_bookmark_tags_spec.rb) covering scenarios for incorrect tags, legitimate work tags, and canonical tags.

Testing Instructions

Prerequisites:

You will need access to the Rails console (bundle exec rails c) or the ability to run Rake tasks.

Steps to Verify:

1. Create a "Dirty" Tag (The Target):

• Create a generic tag (e.g., "Test Dirty Bookmark Tag").
• Ensure it has 0 works.
• Edit the tag and change its type to Character.
• Wrangle it to a Fandom (e.g., "Test Fandom").
• Result: This tag is now "dirty" (Bookmark-only but categorized).

2. Create a "Control" Tag (The Innocent):

• Create another tag (e.g., "Test Work Tag").
• Add it to at least 1 work.
• Edit the tag, make it a Character, and wrangle it to a Fandom.
• Result: This is a legitimate tag that should NOT be touched.

3. Run the Task:

• Run: bundle exec rake tags:reset_bookmark_only

4. Verify Results:

• Check the "Dirty" tag: It should now be listed as Unsorted (Type: Tag) and should not have any Fandom listed.
• Check the "Control" tag: It should still be a Character and still belong to its Fandom.

Credit

Snoopynha
(She/Her)

*On Jira for assign the issues: Camilly Vitória Barbosa dos Santos