Plan 02: ItemContent N+1 Fix & Item Callback Guard

Objective

Fix the potential N+1 in ItemContent's compute_feed_word_count callback and move ensure_feed_content_record into an Item callback so it runs automatically on creation.

Context

• @app/models/source_monitor/item_content.rb -- compute_feed_word_count (line 32) calls item&.content which triggers a lazy load of the item association if not already loaded
• @app/models/source_monitor/item.rb -- ensure_feed_content_record (line 38) is a public method only called from ItemCreator
• item.content is a text column on the sourcemon_items table -- accessing it via the belongs_to :item association loads the full item row if not already in memory

N+1 Analysis

When ItemContent is saved independently (e.g., after scraping), compute_feed_word_count calls item&.content. If the item association isn't preloaded, this triggers a SELECT. This is a single extra query per save (not a classic N+1), but it's avoidable. The fix: extract to a local variable for clarity and ensure the item is loaded.

Tasks

Task 1: Clean up compute_feed_word_count

Files: app/models/source_monitor/item_content.rb

Change compute_feed_word_count (lines 32-39) to use a local variable and add a guard for when item isn't loaded:

def compute_feed_word_count
  feed_content = item&.content
  if feed_content.blank?
    self.feed_word_count = nil
  else
    stripped = ActionView::Base.full_sanitizer.sanitize(feed_content)
    self.feed_word_count = stripped.present? ? stripped.split.size : nil
  end
end

This is a minor clarity improvement -- the local variable feed_content avoids calling item&.content implicitly twice (once for the blank check, once for sanitization in the original code it was only called once, but the local var makes intent clearer).

Tests: Existing item_content_test.rb tests pass unchanged Acceptance: No behavioral change

Task 2: Add after_create_commit callback to Item

Files: app/models/source_monitor/item.rb

Add after the scope declarations (around line 30):

after_create_commit :ensure_feed_content_record, if: -> { content.present? }

The existing ensure_feed_content_record method (line 38) already has guard clauses (return if item_content.present?, return if content.blank?), making this callback safe and idempotent.

Tests: New tests in test/models/source_monitor/item_test.rb Acceptance: Creating an item with content automatically creates an ItemContent record

Task 3: Remove manual ensure_feed_content_record call from ItemCreator

Files: Search with grep -r ensure_feed_content_record lib/ to find call sites

Remove the manual call to ensure_feed_content_record from wherever it's called in the fetching/item creation pipeline. The callback now handles it.

Keep the public method on Item -- it's useful for backfill operations and is idempotent.

Tests: Existing entry_parser_test.rb / item_creator_test.rb tests pass unchanged Acceptance: No manual calls to ensure_feed_content_record after item creation in lib code

Task 4: Write tests for callback behavior

Files: test/models/source_monitor/item_test.rb

Add tests in a new section "ensure_feed_content_record callback":

1. test "creating item with content auto-creates ItemContent" -- create item with content via create!, assert item.reload.item_content present and feed_word_count is computed
2. test "creating item without content does not create ItemContent" -- create item with blank content, assert item.reload.item_content nil
3. test "ensure_feed_content_record is idempotent" -- create item with content (callback fires), call ensure_feed_content_record again, assert still only one ItemContent record

Use create_source! factory. Note: after_create_commit fires after the transaction commits, so use item.reload to check results.

Acceptance: All 3 tests pass

Files

Verification

bin/rails test test/models/source_monitor/item_test.rb test/models/source_monitor/item_content_test.rb
bin/rails test test/lib/source_monitor/fetching/
bin/rubocop app/models/source_monitor/item.rb app/models/source_monitor/item_content.rb

Success Criteria

• Items with content auto-create ItemContent records on creation
• No manual ensure_feed_content_record calls needed after item creation
• compute_feed_word_count uses local variable for clarity
• All existing + new tests pass
• Zero RuboCop offenses