Change the defaults_setter plugin do a deep-copy of database default …

…hash/array values and delegates (Fixes #2069)

CHANGELOG

@@ -1,5 +1,7 @@
 === master
 
+* Change the defaults_setter plugin do a deep-copy of database default hash/array values and delegates (jeremyevans) (#2069)
+
 * Add pg_auto_parameterize_in_array extension, for converting IN/NOT IN to = ANY or != ALL for more types (jeremyevans)
 
 * Fix literalization of infinite and NaN float values in PostgreSQL array bound variables (jeremyevans)

lib/sequel/plugins/defaults_setter.rb

@@ -1,5 +1,7 @@
 # frozen-string-literal: true
 
+require 'delegate'
+
 module Sequel
   module Plugins
     # The defaults_setter plugin makes the column getter methods return the default
@@ -106,6 +108,20 @@ def convert_default_value(v)
             lambda{Date.today}
           when Sequel::CURRENT_TIMESTAMP
             lambda{dataset.current_datetime}
+          when Hash, Array
+            v = Marshal.dump(v).freeze
+            lambda{Marshal.load(v)}
+          when Delegator
+            # DelegateClass returns an anonymous case, which cannot be marshalled, so marshal the
+            # underlying object and create a new instance of the class with the unmarshalled object.
+            klass = v.class
+            case o = v.__getobj__
+            when Hash, Array
+              v = Marshal.dump(o).freeze
+              lambda{klass.new(Marshal.load(v))}
+            else
+              v
+            end
           else
             v
           end

spec/extensions/defaults_setter_spec.rb

@@ -1,5 +1,7 @@
 require_relative "spec_helper"
 
+require 'delegate'
+
 describe "Sequel::Plugins::DefaultsSetter" do
   before do
     @db = db = Sequel.mock
@@ -46,6 +48,46 @@ def db.schema(*) [] end
     (t - Time.now).must_be :<,  1
   end
 
+  it "should not reuse the same default hash for multiple objects" do
+    h = {}
+    c = @pr.call(h)
+    c.new.a.must_equal(h)
+    c.new.a.wont_be_same_as c.new.a
+    c.default_values[:a].must_be_kind_of Proc
+  end
+
+  it "should not reuse the same default array for multiple objects" do
+    h = []
+    c = @pr.call(h)
+    c.new.a.must_equal(h)
+    c.new.a.wont_be_same_as c.new.a
+    c.default_values[:a].must_be_kind_of Proc
+  end
+
+  it "should not reuse the same default hash delegate for multiple objects" do
+    h = DelegateClass(Hash).new({})
+    c = @pr.call(h)
+    c.new.a.must_equal(h)
+    c.new.a.wont_be_same_as c.new.a
+    c.default_values[:a].must_be_kind_of Proc
+  end
+
+  it "should not reuse the same default array delegate for multiple objects" do
+    h = DelegateClass(Array).new([])
+    c = @pr.call(h)
+    c.new.a.must_equal(h)
+    c.new.a.wont_be_same_as c.new.a
+    c.default_values[:a].must_be_kind_of Proc
+  end
+
+  it "should use other object delegates as-is" do
+    h = DelegateClass(Integer).new(1)
+    c = @pr.call(h)
+    c.new.a.must_equal(h)
+    c.new.a.object_id.must_equal c.new.a.object_id
+    c.default_values[:a].object_id.must_equal h.object_id
+  end
+
   it "should handle :callable_default values in schema in preference to :ruby_default" do
     @db.define_singleton_method(:schema) do |*|
       [[:id, {:primary_key=>true}],