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-rw-r--r--activerecord/lib/active_record/associations.rb6
1 files changed, 4 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index cf3e63b4a3..b1951ce83f 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -149,7 +149,9 @@ module ActiveRecord
class HasOneThroughNestedAssociationsAreReadonly < ThroughNestedAssociationsAreReadonly #:nodoc:
end
- class EagerLoadPolymorphicError < ActiveRecordError #:nodoc:
+ # This error is raised when trying to eager load a poloymorphic association using a JOIN.
+ # Eager loading polymorphic associations is only possible with ActiveRecord::QueryMethods#preload.
+ class EagerLoadPolymorphicError < ActiveRecordError
def initialize(reflection = nil)
if reflection
super("Cannot eagerly load the polymorphic association #{reflection.name.inspect}")
@@ -924,7 +926,7 @@ module ActiveRecord
# For example if all the addressables are either of class Person or Company then a total
# of 3 queries will be executed. The list of addressable types to load is determined on
# the back of the addresses loaded. This is not supported if Active Record has to fallback
- # to the previous implementation of eager loading and will raise <tt>ActiveRecord::EagerLoadPolymorphicError</tt>.
+ # to the previous implementation of eager loading and will raise ActiveRecord::EagerLoadPolymorphicError.
# The reason is that the parent model's type is a column value so its corresponding table
# name cannot be put in the +FROM+/+JOIN+ clauses of that query.
#