Merge pull request #7449 from Mik-die/nested-limits

Allow to pass Symbol or Proc into :limit option of #accepts_nested_attributes_for

4 files changed, 49 insertions, 11 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 18b10f1d81..6fb9097809 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Allow to pass Symbol or Proc into :limit option of #accepts_nested_attributes_for
+
+    *Mikhail Dieterle*
+
 *   ActiveRecord::SessionStore has been extracted from Active Record as `activerecord-session_store`
     gem. Please read the `README.md` file on the gem for the usage. *Prem Sichanugrist*
 
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index be013a068c..f91e41b535 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -245,7 +245,8 @@ module ActiveRecord
       #   any value for _destroy.
       # [:limit]
       #   Allows you to specify the maximum number of the associated records that
-      #   can be processed with the nested attributes. If the size of the
+      #   can be processed with the nested attributes. Limit also can be specified as a
+      #   Proc or a Symbol pointing to a method that should return number. If the size of the
       #   nested attributes array exceeds the specified limit, NestedAttributes::TooManyRecords
       #   exception is raised. If omitted, any number associations can be processed.
       #   Note that the :limit option is only applicable to one-to-many associations.
@@ -388,8 +389,17 @@ module ActiveRecord
         raise ArgumentError, "Hash or Array expected, got #{attributes_collection.class.name} (#{attributes_collection.inspect})"
       end
 
-      if options[:limit] && attributes_collection.size > options[:limit]
-        raise TooManyRecords, "Maximum #{options[:limit]} records are allowed. Got #{attributes_collection.size} records instead."
+      limit = case options[:limit]
+      when Symbol
+        send(options[:limit])
+      when Proc
+        options[:limit].call
+      else
+        options[:limit]
+      end
+
+      if limit && attributes_collection.size > limit
+        raise TooManyRecords, "Maximum #{limit} records are allowed. Got #{attributes_collection.size} records instead."
       end
 
       if attributes_collection.is_a? Hash
diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
index 3a234f0cc1..725cff8f01 100644
--- a/activerecord/test/cases/nested_attributes_test.rb
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -846,13 +846,7 @@ class TestNestedAttributesOnAHasAndBelongsToManyAssociation < ActiveRecord::Test
   include NestedAttributesOnACollectionAssociationTests
 end
 
-class TestNestedAttributesLimit < ActiveRecord::TestCase
-  def setup
-    Pirate.accepts_nested_attributes_for :parrots, :limit => 2
-
-    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
-  end
-
+module NestedAttributesLimitTests
   def teardown
     Pirate.accepts_nested_attributes_for :parrots, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? }
   end
@@ -876,6 +870,36 @@ class TestNestedAttributesLimit < ActiveRecord::TestCase
   end
 end
 
+class TestNestedAttributesLimitNumeric < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, :limit => 2
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesLimitSymbol < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, :limit => :parrots_limit
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?", :parrots_limit => 2)
+  end
+
+  include NestedAttributesLimitTests
+end
+
+class TestNestedAttributesLimitProc < ActiveRecord::TestCase
+  def setup
+    Pirate.accepts_nested_attributes_for :parrots, :limit => proc { 2 }
+
+    @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
+  end
+
+  include NestedAttributesLimitTests
+end
+
 class TestNestedAttributesWithNonStandardPrimaryKeys < ActiveRecord::TestCase
   fixtures :owners, :pets
 
diff --git a/activerecord/test/models/pirate.rb b/activerecord/test/models/pirate.rb
index 609b9369a9..170fc2ffe3 100644
--- a/activerecord/test/models/pirate.rb
+++ b/activerecord/test/models/pirate.rb
@@ -53,7 +53,7 @@ class Pirate < ActiveRecord::Base
     attributes.delete('_reject_me_if_new').present? && !persisted?
   end
 
-  attr_accessor :cancel_save_from_callback
+  attr_accessor :cancel_save_from_callback, :parrots_limit
   before_save :cancel_save_callback_method, :if => :cancel_save_from_callback
   def cancel_save_callback_method
     false