perf(reports): avoid residual category lazy loads (#2255)

* perf(reports): avoid residual category lazy loads

* test(reports): reuse SQL query capture helper

Move the reports SQL capture regression helper into test/support and document the category loading and budget reload choices called out in review.

app/models/budget.rb

@@ -90,7 +90,9 @@ class Budget < ApplicationRecord
   end
 
   def sync_budget_categories
-    current_category_ids = family.categories.pluck(:id).to_set
+    # Category changes can leave the association memoized before this sync runs.
+    current_categories_by_id = family.categories.reload.index_by(&:id)
+    current_category_ids = current_categories_by_id.keys.to_set
     existing_budget_category_ids = budget_categories.pluck(:category_id).to_set
     categories_to_add = current_category_ids - existing_budget_category_ids
     categories_to_remove = existing_budget_category_ids - current_category_ids
@@ -98,7 +100,7 @@ class Budget < ApplicationRecord
     # Create missing categories
     categories_to_add.each do |category_id|
       budget_categories.create!(
-        category_id: category_id,
+        category: current_categories_by_id.fetch(category_id),
         budgeted_spending: 0,
         currency: family.currency
       )

app/models/income_statement.rb

@@ -134,7 +134,8 @@ class IncomeStatement
     NetCategoryTotals = Data.define(:net_expense_categories, :net_income_categories, :total_net_expense, :total_net_income, :currency)
 
     def categories
-      @categories ||= family.categories.all.to_a
+      # Keep Category#subcategory?'s parent-based orphan semantics without lazy loads.
+      @categories ||= family.categories.includes(:parent).to_a
     end
 
     def period_cache_key(period)

test/controllers/reports_controller_test.rb

@@ -193,6 +193,40 @@ class ReportsControllerTest < ActionDispatch::IntegrationTest
     assert_select ".text-center.py-8.text-subdued", { text: /No spending data/, count: 0 }, "Should not show 'No spending data' message when transactions exist"
   end
 
+  test "index avoids residual category lazy loads" do
+    account = accounts(:depository)
+
+    4.times do |idx|
+      parent = @family.categories.create!(
+        name: "Reports Parent #{idx}",
+        color: "#000000",
+        lucide_icon: "folder"
+      )
+      child = @family.categories.create!(
+        name: "Reports Child #{idx}",
+        color: "#111111",
+        lucide_icon: "folder",
+        parent: parent
+      )
+      entry = account.entries.create!(
+        name: "Reports transaction #{idx}",
+        date: Date.current,
+        amount: 10 + idx,
+        currency: "USD",
+        entryable: Transaction.new(
+          category: child,
+          kind: "standard"
+        )
+      )
+      assert entry.persisted?
+    end
+
+    queries = capture_sql_queries { get reports_path(period_type: :monthly) }
+
+    assert_response :ok
+    assert_empty queries.grep(/SELECT "categories"\.\* FROM "categories" WHERE "categories"\."id" = \$1 LIMIT \$2/)
+  end
+
   test "export transactions with API key authentication" do
     # Use an active API key with read permissions
     api_key = api_keys(:active_key)

test/models/income_statement_test.rb

@@ -39,6 +39,17 @@ class IncomeStatementTest < ActiveSupport::TestCase
     assert_equal expected_total_expense, expense_totals.category_totals.find { |ct| ct.category.id == @food_category.id }.total
   end
 
+  test "orphaned categories still count as root category totals" do
+    orphan_category = @family.categories.create! name: "Orphaned Category"
+    orphan_category.update_column(:parent_id, SecureRandom.uuid)
+    create_transaction(account: @checking_account, amount: 123, category: orphan_category)
+
+    expense_totals = IncomeStatement.new(@family).expense_totals(period: Period.last_30_days)
+
+    assert_equal 200 + 300 + 400 + 123, expense_totals.total
+    assert_equal 123, expense_totals.category_totals.find { |ct| ct.category.id == orphan_category.id }.total
+  end
+
   test "memoizes expense and income period totals across repeated calculations" do
     income_statement = IncomeStatement.new(@family)
     period = Period.last_30_days