Added :offset and :limit to the kinds of options that Base.constrain can use...

Added :offset and :limit to the kinds of options that Base.constrain can use (closes #2466) [duane.johnson@gmail.com]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2748 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Added :offset and :limit to the kinds of options that Base.constrain can use #2466 [duane.johnson@gmail.com]
+
 * Fixed handling of nil number columns on Oracle and cleaned up tests for Oracle in general #2555 [schoenm@earthlink.net]
 
 * Added quoted_true and quoted_false methods to db2_adapter and cleaned up tests for DB2 #2493 [maik schmidt]

activerecord/lib/active_record/base.rb

@@ -809,7 +809,8 @@ def silence
       end
       
       # Add constraints to all queries to the same model in the given block.
-      # Currently supported constraints are <tt>:conditions</tt> and <tt>:joins</tt> 
+      # Currently supported constraints are <tt>:conditions</tt>, <tt>:joins</tt>,
+      # <tt>:offset</tt>, and <tt>:limit</tt> 
       #
       #   Article.constrain(:conditions => "blog_id = 1") do
       #     Article.find(1) # => SELECT * from articles WHERE blog_id = 1 AND id = 1
@@ -883,6 +884,8 @@ def construct_finder_sql(options)
         end
 
         def add_limit!(sql, options)
+          options[:limit]  ||= scope_constraints[:limit]  if scope_constraints[:limit]
+          options[:offset] ||= scope_constraints[:offset] if scope_constraints[:offset]
           connection.add_limit_offset!(sql, options)
         end
         

activerecord/test/base_test.rb

@@ -1039,6 +1039,30 @@ def test_interpolate_sql
     assert_nothing_raised { Category.new.send(:interpolate_sql, 'foo bar} baz') }
   end
 
+  def test_constrain_conditions
+    developers = Developer.constrain(:conditions => 'salary > 90000') do
+      Developer.find(:all, :conditions => 'id < 5')
+    end
+    david = Developer.find(1)
+    assert !developers.include?(david) # David's salary is less than 90,000
+    assert_equal 3, developers.size
+  end
+  
+  def test_constrain_limit_offset
+    developers = Developer.constrain(:limit => 3, :offset => 2) do
+      Developer.find(:all, :order => 'id')
+    end    
+    david = Developer.find(1)
+    jamis = Developer.find(1)
+    assert !developers.include?(david) # David has id 1
+    assert !developers.include?(jamis) # Jamis has id 2
+    assert_equal 3, developers.size
+    
+    # Now test without constraints to make sure we get the whole thing
+    developers = Developer.find(:all, :order => 'id')
+    assert_equal 10, developers.size
+  end
+  
   # FIXME: this test ought to run, but it needs to run sandboxed so that it
   # doesn't b0rk the current test environment by undefing everything.
   #