Specify pk factory on Collection.new as a :pk option

lib/mongo/collection.rb

@@ -28,6 +28,9 @@ module Mongo
     # @param [DB] db a MongoDB database instance.
     # @param [String, Symbol] name the name of the collection.
     #
+    # @option options [:create_pk] :pk (BSON::ObjectId) A primary key factory to use
+    #   other than the default BSON::ObjectId.
+    #
     # @option options [Boolean, Hash] :safe (false) Set the default safe-mode options
     #   for insert, update, and remove method called on this Collection instance. If no
     #   value is provided, the default value set on this instance's DB will be used. This
@@ -42,7 +45,7 @@ module Mongo
     # @return [Collection]
     #
     # @core collections constructor_details
-    def initialize(db, name, pk_factory=nil, options={})
+    def initialize(db, name, options={})
       case name
       when Symbol, String
       else
@@ -61,11 +64,21 @@ module Mongo
         raise Mongo::InvalidNSName, "collection names must not start or end with '.'"
       end
 
+      if options.respond_to?(:create_pk) || !options.is_a?(Hash)
+        warn "The method for specifying a primary key factory on a Collection has changed.\n" +
+          "Please specify it as an option (e.g., :pk => PkFactory)."
+        pk_factory = options
+      else
+        pk_factory = nil
+      end
+
       @db, @name  = db, name
       @connection = @db.connection
       @logger     = @connection.logger
-      @pk_factory = pk_factory || BSON::ObjectId
+      unless pk_factory
-      @safe       = options.has_key?(:safe) ? options[:safe] : @db.safe
+        @safe       = options.has_key?(:safe) ? options[:safe] : @db.safe
+      end
+      @pk_factory = pk_factory || options[:pk] || BSON::ObjectId
       @hint = nil
     end
 

lib/mongo/db.rb

@@ -255,13 +255,14 @@ module Mongo
       oh = BSON::OrderedHash.new
       oh[:create] = name
       doc = command(oh.merge(options || {}))
-      return Collection.new(self, name, @pk_factory) if ok?(doc)
+      return Collection.new(self, name, :pk => @pk_factory) if ok?(doc)
       raise MongoDBError, "Error creating collection: #{doc.inspect}"
     end
 
     # Get a collection by name.
     #
     # @param [String] name the collection name.
+    # @param [Hash] options any valid options that can me passed to Collection#new.
     #
     # @raise [MongoDBError] if collection does not already exist and we're in +strict+ mode.
     #
@@ -271,7 +272,8 @@ module Mongo
         raise Mongo::MongoDBError, "Collection #{name} doesn't exist. Currently in strict mode."
       else
         options[:safe] = options.has_key?(:safe) ? options[:safe] : @safe
-        Collection.new(self, name, @pk_factory, options)
+        options.merge!(:pk => @pk_factory) unless options[:pk]
+        Collection.new(self, name, options)
       end
     end
     alias_method :[], :collection

test/collection_test.rb

@@ -26,6 +26,20 @@ class TestCollection < Test::Unit::TestCase
     assert @coll.pk_factory.is_a?(Object)
   end
 
+  class TestPK
+    def self.create_pk
+    end
+  end
+
+  def test_pk_factory_on_collection
+    @coll = Collection.new(@@db, 'foo', TestPK)
+    assert_equal TestPK, @coll.pk_factory
+
+
+    @coll2 = Collection.new(@@db, 'foo', :pk => TestPK)
+    assert_equal TestPK, @coll2.pk_factory
+  end
+
   def test_valid_names
     assert_raise Mongo::InvalidNSName do
       @@db["te$t"]

test/unit/safe_test.rb

@@ -48,7 +48,7 @@ class SafeTest < Test::Unit::TestCase
         col = @db.collection('bar', :safe => false)
         assert_equal false, col.safe
 
-        col = Collection.new(@db, 'bar', nil, :safe => false)
+        col = Collection.new(@db, 'bar', :safe => false)
         assert_equal false, col.safe
       end
     end