Guard Function#alias visits for Rails 8.1 compatibility

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## 2.4.0.findy.1      2026-05-13
+* [Findy fork] Guard `visit obj.alias` calls in `MultiTenant::ArelVisitorsDepthFirst` with `respond_to?(:alias)` so the visitor works on Rails 8.1, which removed the `alias` attribute from `Arel::Nodes::Function` (and its `Avg`/`Exists`/`Max`/`Min`/`Sum`/`NamedFunction`/`Count` subclasses). Preserves existing behavior on Rails 6/7/8.0.
+
 ## 2.4.0      2023-09-22
 * Adds citus 12 to test matrix (#210)
 * Adds Support for rails 7.1 (#208)

lib/activerecord-multi-tenant/arel_visitors_depth_first.rb

@@ -39,7 +39,7 @@ def unary(obj)
 
     def function(obj)
       visit obj.expressions
-      visit obj.alias
+      visit obj.alias if obj.respond_to?(:alias)
       visit obj.distinct
     end
     alias visit_Arel_Nodes_Avg    function
@@ -54,12 +54,12 @@ def visit_Arel_Nodes_NamedFunction(obj)
       visit obj.name
       visit obj.expressions
       visit obj.distinct
-      visit obj.alias
+      visit obj.alias if obj.respond_to?(:alias)
     end
 
     def visit_Arel_Nodes_Count(obj)
       visit obj.expressions
-      visit obj.alias
+      visit obj.alias if obj.respond_to?(:alias)
       visit obj.distinct
     end
 

lib/activerecord-multi-tenant/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module MultiTenant
-  VERSION = '2.4.0'
+  VERSION = '2.4.0.findy.1'
 end

spec/activerecord-multi-tenant/arel_visitors_depth_first_spec.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require 'arel'
+require 'activerecord-multi-tenant/arel_visitors_depth_first'
+
+describe MultiTenant::ArelVisitorsDepthFirst do
+  let(:visited) { [] }
+  let(:visitor) { described_class.new(->(node) { visited << node }) }
+  let(:table) { Arel::Table.new(:projects) }
+  let(:expr) { table[:id] }
+
+  describe 'function nodes' do
+    %i[Avg Exists Max Min Sum].each do |const_name|
+      it "traverses Arel::Nodes::#{const_name} without raising" do
+        node = Arel::Nodes.const_get(const_name).new([expr])
+
+        expect { visitor.accept(node) }.not_to raise_error
+        expect(visited).to include(expr)
+      end
+    end
+  end
+
+  describe 'Arel::Nodes::NamedFunction' do
+    it 'traverses the node without raising' do
+      node = Arel::Nodes::NamedFunction.new('coalesce', [expr])
+
+      expect { visitor.accept(node) }.not_to raise_error
+      expect(visited).to include(expr)
+    end
+
+    it 'visits the alias when the node still exposes #alias (Rails <= 8.0)' do
+      node = Arel::Nodes::NamedFunction.new('coalesce', [expr])
+      skip 'Arel::Nodes::NamedFunction#alias was removed in this Rails version' unless node.respond_to?(:alias)
+
+      node.as('id_alias')
+      visitor.accept(node)
+
+      literals = visited.grep(Arel::Nodes::SqlLiteral).map(&:to_s)
+      expect(literals).to include('id_alias')
+    end
+  end
+
+  describe 'Arel::Nodes::Count' do
+    it 'traverses the node without raising' do
+      node = Arel::Nodes::Count.new([expr])
+
+      expect { visitor.accept(node) }.not_to raise_error
+      expect(visited).to include(expr)
+    end
+  end
+end