diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 591433b48c..6dcf02c77f 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Introduce the :readonly option to all associations. Records from the association cannot be saved.  #11084 [miloops]
+
 * Multiparameter attributes for time columns fail over to DateTime when out of range of Time [Geoff Buesing]
 
 * Base#instantiate_time_object uses Time.zone.local() [Geoff Buesing]
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 3ff2d5db6b..4070813ec8 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -669,6 +669,7 @@ module ActiveRecord
       # * <tt>:source_type</tt>: Specifies type of the source association used by <tt>has_many :through</tt> queries where the source
       #   association is a polymorphic +belongs_to+.
       # * <tt>:uniq</tt> - if set to +true+, duplicates will be omitted from the collection. Useful in conjunction with <tt>:through</tt>.
+      # * <tt>:readonly</tt> - if set to +true+, all the associated objects are readonly through the association.
       #
       # Option examples:
       #   has_many :comments, :order => "posted_on"
@@ -677,6 +678,7 @@ module ActiveRecord
       #   has_many :tracks, :order => "position", :dependent => :destroy
       #   has_many :comments, :dependent => :nullify
       #   has_many :tags, :as => :taggable
+      #   has_many :reports, :readonly => true
       #   has_many :subscribers, :through => :subscriptions, :source => :user
       #   has_many :subscribers, :class_name => "Person", :finder_sql =>
       #       'SELECT DISTINCT people.* ' +
@@ -735,13 +737,15 @@ module ActiveRecord
       #   as the default +foreign_key+.
       # * <tt>:include</tt>  - specify second-order associations that should be eager loaded when this object is loaded.
       # * <tt>:as</tt>: Specifies a polymorphic interface (See <tt>#belongs_to</tt>).
-            #
+      # * <tt>:readonly</tt> - if set to +true+, the associated object is readonly through the association.
+      #
       # Option examples:
       #   has_one :credit_card, :dependent => :destroy  # destroys the associated credit card
       #   has_one :credit_card, :dependent => :nullify  # updates the associated records foreign key value to NULL rather than destroying it
       #   has_one :last_comment, :class_name => "Comment", :order => "posted_on"
       #   has_one :project_manager, :class_name => "Person", :conditions => "role = 'project_manager'"
       #   has_one :attachment, :as => :attachable
+      #   has_one :boss, :readonly => :true
       def has_one(association_id, options = {})
         reflection = create_has_one_reflection(association_id, options)
 
@@ -811,6 +815,7 @@ module ActiveRecord
       # * <tt>:polymorphic</tt> - specify this association is a polymorphic association by passing +true+.
       #   Note: If you've enabled the counter cache, then you may want to add the counter cache attribute
       #   to the attr_readonly list in the associated classes (e.g. class Post; attr_readonly :comments_count; end).
+      # * <tt>:readonly</tt> - if set to +true+, the associated object is readonly through the association.
       #
       # Option examples:
       #   belongs_to :firm, :foreign_key => "client_of"
@@ -818,6 +823,7 @@ module ActiveRecord
       #   belongs_to :valid_coupon, :class_name => "Coupon", :foreign_key => "coupon_id",
       #              :conditions => 'discounts > #{payments_count}'
       #   belongs_to :attachable, :polymorphic => true
+      #   belongs_to :project, :readonly => true
       def belongs_to(association_id, options = {})
         reflection = create_belongs_to_reflection(association_id, options)
 
@@ -970,12 +976,14 @@ module ActiveRecord
       # * <tt>:offset</tt>: An integer determining the offset from where the rows should be fetched. So at 5, it would skip the first 4 rows.
       # * <tt>:select</tt>: By default, this is <tt>*</tt> as in <tt>SELECT * FROM</tt>, but can be changed if, for example, you want to do a join
       #   but not include the joined columns.
+      # * <tt>:readonly</tt> - if set to +true+, all the associated objects are readonly through the association.
       #
       # Option examples:
       #   has_and_belongs_to_many :projects
       #   has_and_belongs_to_many :projects, :include => [ :milestones, :manager ]
       #   has_and_belongs_to_many :nations, :class_name => "Country"
       #   has_and_belongs_to_many :categories, :join_table => "prods_cats"
+      #   has_and_belongs_to_many :categories, :readonly => true
       #   has_and_belongs_to_many :active_projects, :join_table => 'developers_projects', :delete_sql =>
       #   'DELETE FROM developers_projects WHERE active=1 AND developer_id = #{id} AND project_id = #{record.id}'
       def has_and_belongs_to_many(association_id, options = {}, &extension)
@@ -1234,7 +1242,7 @@ module ActiveRecord
             :uniq,
             :finder_sql, :counter_sql,
             :before_add, :after_add, :before_remove, :after_remove,
-            :extend
+            :extend, :readonly
           )
 
           options[:extend] = create_extension_modules(association_id, extension, options[:extend])
@@ -1244,7 +1252,7 @@ module ActiveRecord
 
         def create_has_one_reflection(association_id, options)
           options.assert_valid_keys(
-            :class_name, :foreign_key, :remote, :conditions, :order, :include, :dependent, :counter_cache, :extend, :as
+            :class_name, :foreign_key, :remote, :conditions, :order, :include, :dependent, :counter_cache, :extend, :as, :readonly
           )
 
           create_reflection(:has_one, association_id, options, self)
@@ -1253,7 +1261,7 @@ module ActiveRecord
         def create_belongs_to_reflection(association_id, options)
           options.assert_valid_keys(
             :class_name, :foreign_key, :foreign_type, :remote, :conditions, :order, :include, :dependent,
-            :counter_cache, :extend, :polymorphic
+            :counter_cache, :extend, :polymorphic, :readonly
           )
 
           reflection = create_reflection(:belongs_to, association_id, options, self)
@@ -1272,7 +1280,7 @@ module ActiveRecord
             :uniq,
             :finder_sql, :delete_sql, :insert_sql,
             :before_add, :after_add, :before_remove, :after_remove,
-            :extend
+            :extend, :readonly
           )
 
           options[:extend] = create_extension_modules(association_id, extension, options[:extend])
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index d4d3bf7682..9fc0d44a01 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -114,7 +114,8 @@ module ActiveRecord
             :offset  => @reflection.options[:offset],
             :joins   => @reflection.options[:joins],
             :include => @reflection.options[:include],
-            :select  => @reflection.options[:select]
+            :select  => @reflection.options[:select],
+            :readonly  => @reflection.options[:readonly]
           )
         end
 
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
index f5557618c4..9ff3f13592 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -44,7 +44,8 @@ module ActiveRecord
           @reflection.klass.find(
             @owner[@reflection.primary_key_name], 
             :conditions => conditions,
-            :include    => @reflection.options[:include]
+            :include    => @reflection.options[:include],
+            :readonly => @reflection.options[:readonly]
           )
         end
 
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index 312cc1e487..3ff9fe3b9f 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -53,7 +53,8 @@ module ActiveRecord
           @reflection.klass.find(:first, 
             :conditions => @finder_sql, 
             :order      => @reflection.options[:order], 
-            :include    => @reflection.options[:include]
+            :include    => @reflection.options[:include],
+            :readonly    => @reflection.options[:readonly]
           )
         end
 
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
index cfc58ffa10..89b978ad06 100755
--- a/activerecord/test/cases/associations_test.rb
+++ b/activerecord/test/cases/associations_test.rb
@@ -469,6 +469,11 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     end
   end
 
+  def test_cant_save_readonly_association
+    assert_raise(ActiveRecord::ReadOnlyRecord) { companies(:first_firm).readonly_account.save!  }
+    assert companies(:first_firm).readonly_account.readonly?
+  end
+
 end
 
 
@@ -544,6 +549,11 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 2, companies(:first_firm).limited_clients.find_all_by_type('Client', :limit => 9_000).length
   end
 
+  def test_dynamic_find_all_should_respect_readonly_access
+    companies(:first_firm).readonly_clients.find(:all).each { |c| assert_raise(ActiveRecord::ReadOnlyRecord) { c.save!  } }
+    companies(:first_firm).readonly_clients.find(:all).each { |c| assert c.readonly? }
+  end
+
   def test_triple_equality
     assert !(Array === Firm.find(:first).clients)
     assert Firm.find(:first).clients === Array
@@ -1581,6 +1591,11 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal post.author_id, author2.id
   end
 
+  def test_cant_save_readonly_association
+    assert_raise(ActiveRecord::ReadOnlyRecord) { companies(:first_client).readonly_firm.save! }
+    assert companies(:first_client).readonly_firm.readonly?
+  end
+
 end
 
 
@@ -1987,6 +2002,11 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 2, projects(:active_record).limited_developers.find_all_by_name('Jamis', :limit => 9_000).length
   end
 
+  def test_dynamic_find_all_should_respect_readonly_access
+    projects(:active_record).readonly_developers.each { |d| assert_raise(ActiveRecord::ReadOnlyRecord) { d.save!  } if d.valid?}
+    projects(:active_record).readonly_developers.each { |d| d.readonly? }
+  end
+
   def test_new_with_values_in_collection
     jamis = DeveloperForProjectWithAfterCreateHook.find_by_name('Jamis')
     david = DeveloperForProjectWithAfterCreateHook.find_by_name('David')
diff --git a/activerecord/test/cases/reflection_test.rb b/activerecord/test/cases/reflection_test.rb
index c2dedec3ef..c8ee40ea09 100644
--- a/activerecord/test/cases/reflection_test.rb
+++ b/activerecord/test/cases/reflection_test.rb
@@ -159,9 +159,9 @@ class ReflectionTest < ActiveRecord::TestCase
   end
 
   def test_reflection_of_all_associations
-    assert_equal 17, Firm.reflect_on_all_associations.size
-    assert_equal 15, Firm.reflect_on_all_associations(:has_many).size
-    assert_equal 2, Firm.reflect_on_all_associations(:has_one).size
+    assert_equal 19, Firm.reflect_on_all_associations.size
+    assert_equal 16, Firm.reflect_on_all_associations(:has_many).size
+    assert_equal 3, Firm.reflect_on_all_associations(:has_one).size
     assert_equal 0, Firm.reflect_on_all_associations(:belongs_to).size
   end
 
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
index c33f188a02..3d76dfd398 100755
--- a/activerecord/test/models/company.rb
+++ b/activerecord/test/models/company.rb
@@ -40,8 +40,10 @@ class Firm < Company
            :counter_sql => 'SELECT COUNT(*) FROM companies WHERE client_of = 1000'
   has_many :clients_using_finder_sql, :class_name => "Client", :finder_sql => 'SELECT * FROM companies WHERE 1=1'
   has_many :plain_clients, :class_name => 'Client'
+  has_many :readonly_clients, :class_name => 'Client', :readonly => true
 
   has_one :account, :foreign_key => "firm_id", :dependent => :destroy
+  has_one :readonly_account, :foreign_key => "firm_id", :class_name => "Account", :readonly => true
 end
 
 class DependentFirm < Company
@@ -60,6 +62,7 @@ class Client < Company
   belongs_to :firm_with_basic_id, :class_name => "Firm", :foreign_key => "firm_id"
   belongs_to :firm_with_other_name, :class_name => "Firm", :foreign_key => "client_of"
   belongs_to :firm_with_condition, :class_name => "Firm", :foreign_key => "client_of", :conditions => ["1 = ?", 1]
+  belongs_to :readonly_firm, :class_name => "Firm", :foreign_key => "firm_id", :readonly => true
 
   # Record destruction so we can test whether firm.clients.clear has
   # is calling client.destroy, deleting from the database, or setting
diff --git a/activerecord/test/models/project.rb b/activerecord/test/models/project.rb
index b90d2c6fbc..e1ab89eca5 100644
--- a/activerecord/test/models/project.rb
+++ b/activerecord/test/models/project.rb
@@ -1,5 +1,6 @@
 class Project < ActiveRecord::Base
   has_and_belongs_to_many :developers, :uniq => true, :order => 'developers.name desc, developers.id desc'
+  has_and_belongs_to_many :readonly_developers, :class_name => "Developer", :readonly => true
   has_and_belongs_to_many :selected_developers, :class_name => "Developer", :select => "developers.*", :uniq => true
   has_and_belongs_to_many :non_unique_developers, :order => 'developers.name desc, developers.id desc', :class_name => 'Developer'
   has_and_belongs_to_many :limited_developers, :class_name => "Developer", :limit => 1