Optimize PaperTrail whodunnit query in CropsController#show (#4796)

* Optimize PaperTrail whodunnit query in CropsController#show

Replace @crop.versions.map(&:whodunnit) with
@crop.versions.distinct.pluck(:whodunnit) to avoid instantiating all PaperTrail version objects and loading object/object_changes into memory.

Co-authored-by: CloCkWeRX <365751+CloCkWeRX@users.noreply.github.com>

* Optimize PaperTrail whodunnit query in CropsController#show

Replace @crop.versions.map(&:whodunnit) with
@crop.versions.distinct.pluck(:whodunnit) to avoid instantiating all PaperTrail version objects and loading object/object_changes into memory. Added unit test in spec/controllers/crops_controller_spec.rb.

Co-authored-by: CloCkWeRX <365751+CloCkWeRX@users.noreply.github.com>

* Optimize PaperTrail whodunnit query in CropsController#show

Use @crop.versions.reorder(nil).distinct.pluck(:whodunnit) to avoid instantiating all PaperTrail version objects into memory and prevent PostgreSQL PG::InvalidColumnReference errors with SELECT DISTINCT.

Co-authored-by: CloCkWeRX <365751+CloCkWeRX@users.noreply.github.com>

* Fix crop route parameter in controller spec

Update parameter key from id to slug in CropsController show spec to match param: :slug route definition.

Co-authored-by: CloCkWeRX <365751+CloCkWeRX@users.noreply.github.com>

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

app/controllers/crops_controller.rb

@@ -73,7 +73,7 @@ class CropsController < ApplicationController
       format.html do
         @posts = @crop.posts.order(created_at: :desc).paginate(page: params[:page])
         @companions = @crop.companions.approved
-        member_ids = @crop.versions.map(&:whodunnit).compact.map(&:to_i)
+        member_ids = @crop.versions.reorder(nil).distinct.pluck(:whodunnit).compact.map(&:to_i)
         @version_members = Member.where(id: member_ids).index_by(&:id)
       end
       format.svg do

spec/controllers/crops_controller_spec.rb

@@ -28,6 +28,27 @@ describe CropsController do
     end
   end
 
+  describe "GET show" do
+    let!(:crop) { create(:crop) }
+    let!(:member) { create(:member) }
+
+    before do
+      PaperTrail::Version.create!(
+        item_type: 'Crop',
+        item_id: crop.id,
+        event: 'update',
+        whodunnit: member.id.to_s,
+        created_at: Time.current
+      )
+    end
+
+    it "fetches crop show page and sets version members using distinct whodunnit IDs" do
+      get :show, params: { slug: crop.to_param }
+      expect(response).to be_successful
+      expect(assigns(:version_members)).to eq({ member.id => member })
+    end
+  end
+
   describe "GET crop hierarchy" do
     describe 'fetches the crop hierarchy page' do
       context 'wrangler' do