perf(pj service): compute row_id without extraneous requests

app/models/champ.rb

@@ -94,12 +94,6 @@ def stable_id_with_row
     [row_id, stable_id].compact
   end
 
-  def row_index
-    return nil if parent_id.nil?
-
-    Champ.where(parent_id:).pluck(:row_id).sort.index(row_id)
-  end
-
   # used for the `required` html attribute
   # check visibility to avoid hidden required input
   # which prevent the form from being sent.

app/services/pieces_justificatives_service.rb

@@ -142,10 +142,18 @@ def pjs_for_champs(dossiers)
       champs = champs.reject(&:private?)
     end
 
+    champs_id_row_index = champs.select { _1.row_id.present? }.group_by(&:dossier_id).values.each_with_object({}) do |champs_for_dossier, hash|
+      champs_for_dossier.group_by(&:stable_id).values.each do |champs_for_stable_id|
+        champs_for_stable_id.sort_by(&:row_id).each.with_index { |c, index| hash[c.id] = index }
+      end
+    end
+
     champs.flat_map do |champ|
       champ.piece_justificative_file_attachments.map.with_index do |attachment, index|
+        row_index = champs_id_row_index[champ.id]
+
         if @export_template
-          @export_template.attachment_and_path(champ.dossier, attachment, index:, row_index: champ.row_index, champ:)
+          @export_template.attachment_and_path(champ.dossier, attachment, index:, row_index:, champ:)
         else
           ActiveStorage::DownloadableFile.pj_and_path(champ.dossier_id, attachment)
         end

spec/services/procedure_export_service_zip_spec.rb

@@ -40,7 +40,7 @@ def attachments(champ) = champ.piece_justificative_file.attachments
               subject
             end
 
-            expect(sql_count).to eq(89)
+            expect(sql_count).to eq(58)
 
             dossier = dossiers.first
 
@@ -58,7 +58,7 @@ def attachments(champ) = champ.piece_justificative_file.attachments
                 "export/dossier-#{dossier.id}/libelle-du-champ-2-#{dossier.id}-1-2.png"
               ]
 
-              expect(files.size).to eq(10 * 6 + 1)
+              expect(files.size).to eq(dossiers.count * 6 + 1)
               expect(structure - files.map(&:filename)).to be_empty
             end
             FileUtils.remove_entry_secure('tmp.zip')