Merge pull request rails#46864 from palkan/feat/arel-function-tables

Support function table names in Arel Table

Author: rafaelfranca

activerecord/lib/arel/table.rb

@@ -10,11 +10,14 @@ class << self; attr_accessor :engine; end
 
     attr_accessor :name, :table_alias
 
-    # TableAlias and Table both have a #table_name which is the name of the underlying table
-    alias :table_name :name
-
     def initialize(name, as: nil, klass: nil, type_caster: klass&.type_caster)
-      @name = name.to_s
+      @name =
+        case name
+        when Symbol then name.to_s
+        else
+          name
+        end
+
       @klass = klass
       @type_caster = type_caster
 

activerecord/lib/arel/visitors/to_sql.rb

@@ -568,11 +568,17 @@ def visit_Arel_Nodes_Not(o, collector)
         end
 
         def visit_Arel_Table(o, collector)
-          if o.table_alias
-            collector << quote_table_name(o.name) << " " << quote_table_name(o.table_alias)
+          if Arel::Nodes::Node === o.name
+            visit o.name, collector
           else
             collector << quote_table_name(o.name)
           end
+
+          if o.table_alias
+            collector << " " << quote_table_name(o.table_alias)
+          end
+
+          collector
         end
 
         def visit_Arel_Nodes_In(o, collector)

activerecord/test/cases/arel/table_test.rb

@@ -127,6 +127,17 @@ class TableTest < Arel::Spec
         rel = Table.new :users, as: "users"
         _(rel.table_alias).must_be_nil
       end
+
+      it "should accept literal SQL"  do
+        rel = Table.new Arel.sql("generate_series(4, 2)")
+        assert_equal Arel.sql("generate_series(4, 2)"), rel.name
+      end
+
+      it "should accept Arel nodes"  do
+        node = Arel::Nodes::NamedFunction.new("generate_series", [4, 2])
+        rel = Table.new node
+        assert_equal node, rel.name
+      end
     end
 
     describe "order" do
@@ -173,10 +184,6 @@ class TableTest < Arel::Spec
       _(@relation.name).must_equal "users"
     end
 
-    it "should have a table name" do
-      _(@relation.table_name).must_equal "users"
-    end
-
     describe "[]" do
       describe "when given a Symbol" do
         it "manufactures an attribute if the symbol names an attribute within the relation" do

activerecord/test/cases/arel/visitors/to_sql_test.rb

@@ -726,6 +726,31 @@ def dispatch
         end
       end
 
+      describe "Table" do
+        it "should compile node names" do
+          test = Table.new(:users).alias("zomgusers")[:id].eq "3"
+          _(compile(test)).must_be_like %{
+            "zomgusers"."id" = '3'
+          }
+        end
+
+        it "should compile literal SQL"  do
+          test = Table.new Arel.sql("generate_series(4, 2)")
+          _(compile(test)).must_be_like %{ generate_series(4, 2) }
+        end
+
+        it "should compile Arel nodes"  do
+          test = Arel::Nodes::NamedFunction.new("generate_series", [4, 2])
+          _(compile(test)).must_be_like %{ generate_series(4, 2) }
+        end
+
+        it "should compile nodes with bind params" do
+          bp = Nodes::BindParam.new(1)
+          test = Arel::Nodes::NamedFunction.new("generate_series", [4, bp])
+          _(compile(test)).must_be_like %{ generate_series(4, ?) }
+        end
+      end
+
       describe "TableAlias" do
         it "should use the underlying table for checking columns" do
           test = Table.new(:users).alias("zomgusers")[:id].eq "3"