feat: show counterpart account in transfer transaction list row (#2643)

* Show counterpart account in transfer transaction list row

* feat: show transfer counterpart account with access and nil guards

* - Gate counterpart name behind accessible_accounts check.
- Add nested transfer includes to TransactionsController and
AccountsController to prevent N+1 queries.
- Use precomputed @accessible_account_ids Set for O(1) lookups.

* test: add view tests for transfer counterpart rendering

Cover outflow arrow, inflow arrow, and unmatched transfer fallback
using ActionView::TestCase following existing merged_badge pattern.

* Fix transfer eager loading for polymorphic entryables

* Keep accessible_account_ids as Array to fix mock test expectations

app/controllers/accounts_controller.rb

@@ -57,8 +57,10 @@ class AccountsController < ApplicationController
   def show
     @chart_view = params[:chart_view] || "balance"
     @tab = params[:tab]
+    @accessible_account_ids = Current.user.accessible_accounts.pluck(:id).to_set
     @q = params.fetch(:q, {}).permit(:search, status: [])
     entries = @account.entries.where(excluded: false).search(@q).reverse_chronological.includes(:entryable)
+
     if statement_tab_active?
       build_statement_tab_data
       return render_statement_tab_frame if statement_tab_frame_request?
@@ -69,6 +71,17 @@ class AccountsController < ApplicationController
       limit: safe_per_page,
       params: request.query_parameters.except("tab").merge("tab" => "activity")
     )
+
+    # Preload transfer associations only for Transaction entries
+    txn_entryables = @entries.filter_map { |e| e.entryable if e.entryable_type == "Transaction" }
+    ActiveRecord::Associations::Preloader.new(
+      records: txn_entryables,
+      associations: {
+        transfer_as_outflow: { inflow_transaction: { entry: :account } },
+        transfer_as_inflow: { outflow_transaction: { entry: :account } }
+      }
+    ).call
+
     Transaction::ActivitySecurityPreloader.new(@entries).preload
 
     @activity_feed_data = Account::ActivityFeedData.new(@account, @entries)

app/controllers/transactions_controller.rb

@@ -14,16 +14,17 @@ class TransactionsController < ApplicationController
 
   def index
     @q = search_params
-    accessible_account_ids = Current.user.accessible_accounts.pluck(:id)
-    @search = Transaction::Search.new(Current.family, filters: @q, accessible_account_ids: accessible_account_ids)
+    @accessible_account_ids = Current.user.accessible_accounts.pluck(:id)
+    @search = Transaction::Search.new(Current.family, filters: @q, accessible_account_ids: @accessible_account_ids)
 
     base_scope = @search.transactions_scope
                        .reverse_chronological
                        .includes(
-                         { entry: :account },
-                         :category, :merchant, :tags,
-                         :transfer_as_inflow, :transfer_as_outflow
-                       )
+                          { entry: :account },
+                          :category, :merchant, :tags,
+                          transfer_as_outflow: { inflow_transaction: { entry: :account } },
+                          transfer_as_inflow: { outflow_transaction: { entry: :account } }
+                        )
 
     @pagy, @transactions = pagy(base_scope, limit: safe_per_page)
     Transaction::ActivitySecurityPreloader.new(@transactions).preload

app/views/transactions/_transaction.html.erb

@@ -153,7 +153,21 @@
                 <div class="text-secondary text-xs font-normal">
                   <% if transaction.transfer? %>
                     <span class="text-secondary">
-                      <%= transaction.loan_payment? ? t("transactions.show.loan_payment") : t("transactions.show.transfer") %> • <%= entry.account.name %>
+                      <%= transaction.loan_payment? ? t("transactions.show.loan_payment") : t("transactions.show.transfer") %> •
+                      <% if transaction.transfer.present? %>
+                        <% counterpart = transaction.transfer_as_outflow.present? ? transaction.transfer.to_account : transaction.transfer.from_account %>
+                        <% if counterpart.present? && @accessible_account_ids&.include?(counterpart.id) %>
+                          <% if transaction.transfer_as_outflow.present? %>
+                            <%= entry.account.name %> → <%= counterpart.name %>
+                          <% else %>
+                            <%= entry.account.name %> ← <%= counterpart.name %>
+                          <% end %>
+                        <% else %>
+                          <%= entry.account.name %>
+                        <% end %>
+                      <% else %>
+                        <%= entry.account.name %>
+                      <% end %>
                     </span>
                   <% else %>
                     <% if transaction.merchant&.present? %>

test/views/transactions/transfer_counterpart_view_test.rb

@@ -0,0 +1,85 @@
+require "test_helper"
+
+class Transactions::TransferCounterpartViewTest < ActionView::TestCase
+  setup do
+    @family = families(:dylan_family)
+    @user = users(:family_admin)
+    Current.session = Session.create!(user: @user)
+
+    @checking = accounts(:depository) # "from" account
+    @savings = accounts(:credit_card) # "to" account
+
+    @accessible_account_ids = @user.accessible_accounts.pluck(:id).to_set
+    @split_parent_entry_ids = Set.new
+  end
+
+  test "renders outflow transfer with arrow to destination account" do
+    outflow_tx = Transaction.create!(kind: "funds_movement")
+    outflow_entry = Entry.create!(
+      account: @checking, entryable: outflow_tx,
+      name: "Transfer to Savings", amount: 100, currency: "USD", date: Date.today
+    )
+
+    inflow_tx = Transaction.create!(kind: "funds_movement")
+    inflow_entry = Entry.create!(
+      account: @savings, entryable: inflow_tx,
+      name: "Transfer from Checking", amount: -100, currency: "USD", date: Date.today
+    )
+
+    Transfer.create!(
+      inflow_transaction: inflow_tx,
+      outflow_transaction: outflow_tx,
+      status: "confirmed"
+    )
+
+    html = render(partial: "transactions/transaction", locals: {
+      entry: outflow_entry, balance_trend: nil, view_ctx: "global"
+    })
+
+    assert_includes html, "→"
+    assert_includes html, @savings.name
+  end
+
+  test "renders inflow transfer with arrow from source account" do
+    outflow_tx = Transaction.create!(kind: "funds_movement")
+    outflow_entry = Entry.create!(
+      account: @checking, entryable: outflow_tx,
+      name: "Transfer to Savings", amount: 100, currency: "USD", date: Date.today
+    )
+
+    inflow_tx = Transaction.create!(kind: "funds_movement")
+    inflow_entry = Entry.create!(
+      account: @savings, entryable: inflow_tx,
+      name: "Transfer from Checking", amount: -100, currency: "USD", date: Date.today
+    )
+
+    Transfer.create!(
+      inflow_transaction: inflow_tx,
+      outflow_transaction: outflow_tx,
+      status: "confirmed"
+    )
+
+    html = render(partial: "transactions/transaction", locals: {
+      entry: inflow_entry, balance_trend: nil, view_ctx: "global"
+    })
+
+    assert_includes html, "←"
+    assert_includes html, @checking.name
+  end
+
+  test "falls back to account name when transfer has no counterpart" do
+    tx = Transaction.create!(kind: "funds_movement")
+    entry = Entry.create!(
+      account: @checking, entryable: tx,
+      name: "Unmatched Transfer", amount: 100, currency: "USD", date: Date.today
+    )
+
+    html = render(partial: "transactions/transaction", locals: {
+      entry: entry, balance_trend: nil, view_ctx: "global"
+    })
+
+    assert_includes html, @checking.name
+    assert_not_includes html, "→"
+    assert_not_includes html, "←"
+  end
+end