Ambiguous reflections are on :through relationships are no longer supported.

For example, you need to change this:

  class Author < ActiveRecord::Base
    has_many :posts
    has_many :taggings, :through => :posts
  end

  class Post < ActiveRecord::Base
    has_one :tagging
    has_many :taggings
  end

  class Tagging < ActiveRecord::Base
  end

To this:

  class Author < ActiveRecord::Base
    has_many :posts
    has_many :taggings, :through => :posts, :source => :tagging
  end

  class Post < ActiveRecord::Base
    has_one :tagging
    has_many :taggings
  end

  class Tagging < ActiveRecord::Base
  end

2 files changed, 2 insertions, 2 deletions

diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
index a96899ae10..af80b1ba42 100644
--- a/activerecord/test/models/author.rb
+++ b/activerecord/test/models/author.rb
@@ -85,7 +85,7 @@ class Author < ActiveRecord::Base
   has_many :author_favorites
   has_many :favorite_authors, -> { order('name') }, :through => :author_favorites
 
-  has_many :taggings,        :through => :posts
+  has_many :taggings,        :through => :posts, :source => :taggings
   has_many :taggings_2,      :through => :posts, :source => :tagging
   has_many :tags,            :through => :posts
   has_many :post_categories, :through => :posts, :source => :categories
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
index dcda62e71d..b988184f34 100644
--- a/activerecord/test/models/company.rb
+++ b/activerecord/test/models/company.rb
@@ -141,7 +141,7 @@ class Client < Company
   belongs_to :firm_with_primary_key_symbols, :class_name => "Firm", :primary_key => :name, :foreign_key => :firm_name
   belongs_to :readonly_firm, -> { readonly }, :class_name => "Firm", :foreign_key => "firm_id"
   belongs_to :bob_firm, -> { where :name => "Bob" }, :class_name => "Firm", :foreign_key => "client_of"
-  has_many :accounts, :through => :firm
+  has_many :accounts, :through => :firm, :source => :accounts
   belongs_to :account
 
   class RaisedOnSave < RuntimeError; end