add default scopes to through unions

Author: ezekg

lib/union_of.rb

@@ -218,7 +218,11 @@ def next_chain_scope(scope, reflection, next_reflection)
       table         = klass.arel_table
       foreign_klass = next_reflection.klass
       foreign_table = foreign_klass.arel_table
-      constraints   = []
+
+      # This holds our union's constraints. For example, if we're unioning across 3
+      # tables, then this will hold constraints for all 3 of those tables, so that
+      # the join on our target table mirrors the union of all 3 associations.
+      foreign_constraints = []
 
       reflection.union_sources.each do |union_source|
         union_reflection = foreign_klass.reflect_on_association(union_source)
@@ -231,21 +235,33 @@ def next_chain_scope(scope, reflection, next_reflection)
             through_reflection.name,
           )
 
-          constraints << foreign_table[through_reflection.join_foreign_key].eq(through_table[through_reflection.join_primary_key])
+          foreign_constraints << foreign_table[through_reflection.join_foreign_key].eq(through_table[through_reflection.join_primary_key])
         else
-          constraints << foreign_table[union_reflection.join_foreign_key].eq(table[union_reflection.join_primary_key])
+          foreign_constraints << foreign_table[union_reflection.join_foreign_key].eq(table[union_reflection.join_primary_key])
         end
       end
 
+      # Flatten union constraints and add any default constraints
+      foreign_constraint = unless (where_clause = foreign_klass.default_scoped.where_clause).empty?
+                             where_clause.ast.and(foreign_constraints.reduce(&:or))
+                           else
+                             foreign_constraints.reduce(&:or)
+                           end
+
       scope.joins!(
         Arel::Nodes::InnerJoin.new(
           foreign_table,
           Arel::Nodes::On.new(
-            constraints.reduce(&:or),
+            foreign_constraint,
           ),
         ),
       )
 
+      # FIXME(ezekg) Why is this needed? Should be handled automatically...
+      scope.merge!(
+        scope.default_scoped,
+      )
+
       scope
     end
 
@@ -278,7 +294,7 @@ def join_scope(table, foreign_table, foreign_klass, alias_tracker = nil)
       # This holds our union's constraints. For example, if we're unioning across 3
       # tables, then this will hold constraints for all 3 of those tables, so that
       # the join on our target table mirrors the union of all 3 associations.
-      constraints = []
+      foreign_constraints = []
 
       union_sources.each do |union_source|
         union_reflection = foreign_klass.reflect_on_association(union_source)
@@ -297,29 +313,31 @@ def join_scope(table, foreign_table, foreign_klass, alias_tracker = nil)
           end
 
           # Create base join constraints and add default constraints if available
-          through_constraints = through_table[through_reflection.join_primary_key].eq(
+          through_constraint = through_table[through_reflection.join_primary_key].eq(
             foreign_table[through_reflection.join_foreign_key],
           )
 
           unless (where_clause = through_klass.default_scoped.where_clause).empty?
-            through_constraints = where_clause.ast.and(through_constraints)
+            through_constraint = where_clause.ast.and(through_constraint)
           end
 
           klass_scope.joins!(
             Arel::Nodes::OuterJoin.new(
               through_table,
-              Arel::Nodes::On.new(through_constraints),
+              Arel::Nodes::On.new(through_constraint),
             ),
           )
 
-          constraints << table[source_reflection.join_primary_key].eq(through_table[source_reflection.join_foreign_key])
+          foreign_constraints << table[source_reflection.join_primary_key].eq(through_table[source_reflection.join_foreign_key])
         else
-          constraints << table[union_reflection.join_primary_key].eq(foreign_table[union_reflection.join_foreign_key])
+          foreign_constraints << table[union_reflection.join_primary_key].eq(foreign_table[union_reflection.join_foreign_key])
         end
       end
 
-      unless constraints.empty?
-        klass_scope.where!(constraints.reduce(&:or))
+      unless foreign_constraints.empty?
+        foreign_constraint = foreign_constraints.reduce(&:or)
+
+        klass_scope.where!(foreign_constraint)
       end
 
       unless scope_chain_items.empty?

spec/lib/union_of_spec.rb

@@ -398,6 +398,8 @@
         )
       WHERE
         "licenses"."id" = '#{license.id}'
+      ORDER BY
+        "users"."created_at" ASC
     SQL
   end