Don't use identity map if loading readonly records, this will prevent…

… changing readonly status on already loaded records.

activerecord/lib/active_record/relation.rb

@@ -61,15 +61,22 @@ def respond_to?(method, include_private = false)
     def to_a
       return @records if loaded?
 
-      @records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql, @bind_values)
+      readonly = @readonly_value.nil? ? @implicit_readonly : @readonly_value
+
+      @records = if readonly
+        IdentityMap.without do
+          eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql, @bind_values)
+        end
+      else
+        eager_loading? ? find_with_associations : @klass.find_by_sql(arel.to_sql, @bind_values)
+      end
 
       preload = @preload_values
       preload +=  @includes_values unless eager_loading?
       preload.each {|associations| @klass.send(:preload_associations, @records, associations) }
 
       # @readonly_value is true only if set explicitly. @implicit_readonly is true if there
       # are JOINS and no explicit SELECT.
-      readonly = @readonly_value.nil? ? @implicit_readonly : @readonly_value
       @records.each { |record| record.readonly! } if readonly
 
       @loaded = true

activerecord/test/cases/identity_map_test.rb

@@ -242,12 +242,6 @@ def test_eager_loading_with_conditions_on_string_joined_table_preloads
     assert_equal authors(:david), assert_no_queries { posts[0].author}
   end
 
-  # Second search should not change read only status for collection
-  def test_find_with_joins_option_implies_readonly
-    Developer.joins(', projects').each { |d| assert d.readonly? }
-    Developer.joins(', projects').readonly(false).each { |d| assert d.readonly? }
-  end
-
   def test_reload_object_if_save_failed
     developer = Developer.first
     developer.salary = 0
@@ -305,4 +299,30 @@ def test_associated_object_are_assigned_from_identity_map
       assert_equal post.object_id, comment.post.target.object_id
     end
   end
+
+  def test_find_using_identity_map_respects_readonly_when_loading_associated_object_first
+    author  = Author.first
+    readonly_comment = author.readonly_comments.first
+
+    comment = Comment.first
+    assert !comment.readonly?
+
+    assert readonly_comment.readonly?
+
+    assert_raise(ActiveRecord::ReadOnlyRecord) {readonly_comment.save}
+    assert comment.save
+  end
+
+  def test_find_using_identity_map_respects_readonly
+    comment = Comment.first
+    assert !comment.readonly?
+
+    author  = Author.first
+    readonly_comment = author.readonly_comments.first
+
+    assert readonly_comment.readonly?
+
+    assert_raise(ActiveRecord::ReadOnlyRecord) {readonly_comment.save}
+    assert comment.save
+  end
 end