Limit tactically eager loading to objects that have the same associat…

…ion reflection

In cases where inheritance is used, a subclass could define an
association with the same name differently than a parent class.
In this case, attempting to eager load may cause problems.

CHANGELOG

@@ -1,5 +1,7 @@
 === master
 
+* Limit tactically eager loading to objects that have the same association reflection (jeremyevans) (#2181)
+
 * Fix race condition in threaded/sharded_threaded connection pools that could cause stalls (jeremyevans)
 
 * Emulate dropping a unique column or a column that is part of an index on SQLite 3.35.0+ (jeremyevans) (#2176)

lib/sequel/plugins/tactical_eager_loading.rb

@@ -158,15 +158,19 @@ def load_associated_objects(opts, dynamic_opts=OPTS, &block)
         end
 
         # Filter the objects used when tactical eager loading.
-        # By default, this removes frozen objects and objects that alreayd have the association loaded
+        # By default, this removes frozen objects and objects that alreayd have the association loaded,
+        # as well as objects where the reflection for the association is not the same as the receiver's
+        # reflection for the association.
         def _filter_tactical_eager_load_objects(opts)
           objects = defined?(super) ? super : retrieved_with.dup
+          name = opts[:name]
           if opts[:eager_reload]
             objects.reject!(&:frozen?)
           else
-            name = opts[:name]
             objects.reject!{|x| x.frozen? || x.associations.include?(name)}
           end
+          reflection = self.class.association_reflection(name)
+          objects.select!{|x| x.class.association_reflection(name).equal?(reflection)}
           objects
         end
       end

spec/extensions/tactical_eager_loading_spec.rb

@@ -179,6 +179,12 @@ class ::TacticalEagerLoadingModel < Sequel::Model(:t)
     sql_match('SELECT * FROM t', 'SELECT * FROM t WHERE (t.id IN (101, 102))')
     objs[0].associations.keys.must_equal [:parent]
     objs[1].associations.keys.must_equal [:parent]
+
+    c.many_to_one :parent, :class=>@c, :key=>:parent_id
+    objs = @c.dataset.with_row_proc(proc{|r| (r[:parent_id] == 101 ? c : @c).call(r)}).all{|x| x.parent if x.is_a?(c)}
+    sql_match('SELECT * FROM t', 'SELECT * FROM t WHERE (t.id IN (101))')
+    objs[0].associations.keys.must_equal [:parent]
+    objs[1].associations.keys.must_equal []
   end
 
   it "association getter methods should not eagerly load the association if an instance is frozen" do