Destroy associated has_and_belongs_to_many records after all before_destroy callbacks but before destroy. This allows you to act on the habtm association as you please while preserving referential integrity. Closes #2065.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2940 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 16 insertions, 3 deletions

diff --git a/activerecord/test/associations_test.rb b/activerecord/test/associations_test.rb
index fc2afb721f..4ad40f338c 100755
--- a/activerecord/test/associations_test.rb
+++ b/activerecord/test/associations_test.rb
@@ -1246,10 +1246,13 @@ class HasAndBelongsToManyAssociationsTest < Test::Unit::TestCase
   end
 
   def test_removing_associations_on_destroy
-    Developer.find(1).destroy
-    assert Developer.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = 1").empty?
+    david = DeveloperWithBeforeDestroyRaise.find(1)
+    assert !david.projects.empty?
+    assert_nothing_raised { david.destroy }
+    assert david.projects.empty?
+    assert DeveloperWithBeforeDestroyRaise.connection.select_all("SELECT * FROM developers_projects WHERE developer_id = 1").empty?
   end
-  
+
   def test_additional_columns_from_join_table
     # SQL Server doesn't have a separate column type just for dates, 
     # so the time is in the string and incorrectly formatted
diff --git a/activerecord/test/fixtures/developer.rb b/activerecord/test/fixtures/developer.rb
index ce65ff78c0..29555d926a 100644
--- a/activerecord/test/fixtures/developer.rb
+++ b/activerecord/test/fixtures/developer.rb
@@ -28,3 +28,13 @@ class DeveloperWithAggregate < ActiveRecord::Base
   self.table_name = 'developers'
   composed_of :salary, :class_name => 'DeveloperSalary', :mapping => [%w(salary amount)]
 end
+
+class DeveloperWithBeforeDestroyRaise < ActiveRecord::Base
+  self.table_name = 'developers'
+  has_and_belongs_to_many :projects, :join_table => 'developers_projects', :foreign_key => 'developer_id'
+  before_destroy :raise_if_projects_empty!
+
+  def raise_if_projects_empty!
+    raise if projects.empty?
+  end
+end