Fixing issue with required bool fields (#461)

* Fixing issue where a required validation on a bool field would fail if the value was false. Fixes #457

* applying spec cleanup changes

* Removing this box since it's not actually needed for anything

spec/save_operation_spec.cr

@@ -16,6 +16,14 @@ private class SaveUser < User::SaveOperation
   end
 end
 
+private class SaveUserWithFalseValueValidations < User::SaveOperation
+  permit_columns :nickname, :available_for_hire
+
+  before_save do
+    validate_required nickname, available_for_hire
+  end
+end
+
 private class SaveLimitedUser < User::SaveOperation
   permit_columns :name
 end
@@ -428,6 +436,13 @@ describe "Avram::SaveOperation" do
           r.drafted_at.should eq drafted_at
         end
       end
+
+      it "updates with a record that has defaults" do
+        model = ModelWithDefaultValues::SaveOperation.create!
+        record = OverrideDefaults.update!(model, greeting: "Hi")
+        record.greeting.should eq "Hi"
+        record.admin.should eq false
+      end
     end
   end
 
@@ -553,6 +568,20 @@ describe "Avram::SaveOperation" do
         end
       end
     end
+
+    context "when the default is false and the field is required" do
+      it "is valid since 'false' is a valid Boolean value" do
+        user = UserBox.create &.nickname("oopsie").available_for_hire(false)
+        params = Avram::Params.new({"nickname" => "falsey mcfalserson"})
+        SaveUserWithFalseValueValidations.update(user, params) do |operation, record|
+          record.should_not eq nil
+          r = record.not_nil!
+          operation.valid?.should be_true
+          r.nickname.should eq "falsey mcfalserson"
+          r.available_for_hire.should eq false
+        end
+      end
+    end
   end
 
   describe ".update!" do

src/avram/save_operation.cr

@@ -120,10 +120,13 @@ abstract class Avram::SaveOperation(T) < Avram::Operation
       end
 
       private def _{{ attribute[:name] }}
+        record_value = @record.try(&.{{ attribute[:name] }})
+        value = record_value.nil? ? default_value_for_{{ attribute[:name] }} : record_value
+
         @_{{ attribute[:name] }} ||= Avram::Attribute({{ attribute[:type] }}?).new(
           name: :{{ attribute[:name].id }},
           param: permitted_params["{{ attribute[:name] }}"]?,
-          value: @record.try(&.{{ attribute[:name] }}) || default_value_for_{{ attribute[:name] }},
+          value: value,
           param_key: self.class.param_key)
       end