Deprecate Spree::Payment offsets

core/app/models/spree/order.rb

@@ -572,7 +572,7 @@ def quantity
 
     def has_non_reimbursement_related_refunds?
       refunds.non_reimbursement.exists? ||
-        payments.offset_payment.exists? # how old versions of spree stored refunds
+        payments.where("source_type = 'Spree::Payment' AND amount < 0 AND state = 'completed'").exists? # how old versions of spree stored refunds
     end
 
     def tax_total

core/app/models/spree/payment.rb

@@ -46,7 +46,18 @@ class Payment < Spree::Base
     scope :from_credit_card, -> { where(source_type: 'Spree::CreditCard') }
     scope :with_state, ->(state) { where(state: state.to_s) }
     # "offset" is reserved by activerecord
-    scope :offset_payment, -> { where("source_type = 'Spree::Payment' AND amount < 0 AND state = 'completed'") }
+    # TODO: When removing the method we can also:
+    #   - Remove the `.offsets` association
+    #   - Remove the `#offsets_total` method
+    #   - Remove offsets count from the `#credit_allowed` method
+    #   - Remove offsets check from `Spree::Order#has_non_reimbursement_related_refunds?
+    def self.offset_payment
+      Spree::Deprecation.warn <<~MSG
+        `Spree::Payment offsets` are deprecated. Use the refund system (`Spree::Refund`) instead.
+      MSG
+
+      where("source_type = 'Spree::Payment' AND amount < 0 AND state = 'completed'")
+    end
 
     scope :checkout, -> { with_state('checkout') }
     scope :completed, -> { with_state('completed') }
@@ -101,7 +112,10 @@ def offsets_total
     # @return [BigDecimal] the amount of this payment minus the offsets
     #   (old-style refunds) and refunds
     def credit_allowed
-      amount - (offsets_total.abs + refunds.sum(:amount))
+      amount - (
+        (self.class.where("source_type = 'Spree::Payment' AND amount < 0 AND state = 'completed' AND source_id = ?", id).sum(:amount)).abs +
+        refunds.sum(:amount)
+      )
     end
 
     # @return [Boolean] true when this payment can be credited

core/spec/models/spree/payment_spec.rb

@@ -671,11 +671,18 @@
     # Regression test for https://github.com/spree/spree/issues/4403 and https://github.com/spree/spree/issues/4407
     it "is the difference between offsets total and payment amount" do
       payment.amount = 100
-      allow(payment).to receive(:offsets_total).and_return(0)
       expect(payment.credit_allowed).to eq(100)
-      allow(payment).to receive(:offsets_total).and_return(-80)
+      create(:payment, amount: -80, source: payment, source_type: 'Spree::Payment', state: 'completed', payment_method: create(:check_payment_method))
       expect(payment.credit_allowed).to eq(20)
     end
+
+    it "is the difference between refunds total and payment amount" do
+      payment.amount = 100
+
+      expect {
+        create(:refund, payment: payment, amount: 80)
+      }.to change { payment.credit_allowed }.from(100).to(20)
+    end
   end
 
   describe "#can_credit?" do
@@ -1332,4 +1339,18 @@
       expect(described_class.valid).to be_empty
     end
   end
+
+  describe '::offset_payment' do
+    it 'is deprecated' do
+      expect(Spree::Deprecation).to receive(:warn).with(/offsets` are deprecated/)
+
+      described_class.offset_payment
+    end
+
+    it 'still calls the original method' do
+      Spree::Deprecation.silence do
+        expect(described_class.offset_payment.class.name).to eq('ActiveRecord::Relation')
+      end
+    end
+  end
 end