[dm-validations] Make it possible to use callable objects for message…

…s, requires Edge Extlib

This makes it possible to construct complex custom error messages and not add
more and more and more ad hoc error messages to default set

 * ValidationErrors objects are now aware of models they are attached to (#model accessor)
 * For pure Ruby objects, if :message is a callable, model (object) is yielded to it
 * For DM resources, if :message is a callable, model AND property are yielded to it

[#769 state:resolved]

dm-validations/lib/dm-validations.rb

@@ -73,7 +73,7 @@ def save!
     # Return the ValidationErrors
     #
     def errors
-      @errors ||= ValidationErrors.new
+      @errors ||= ValidationErrors.new(self)
     end
 
     # Mark this resource as validatable. When we validate associations of a

dm-validations/lib/dm-validations/validation_errors.rb

@@ -41,6 +41,13 @@ def self.default_error_message(key, field, *values)
         @@default_error_messages[key] % [field, *values].flatten
       end
 
+      attr_reader :model
+
+      def initialize(model)
+        @model  = model
+        @errors = {}
+      end
+
       # Clear existing validation errors.
       def clear!
         errors.clear
@@ -52,6 +59,17 @@ def clear!
       # @param [Symbol] field_name the name of the field that caused the error
       # @param [String] message    the message to add
       def add(field_name, message)
+        # see 6abe8fff in extlib, but don't enforce
+        # it unless Edge version is installed
+        if message.respond_to?(:try_call)
+          # DM model
+          message = if model.class.respond_to?(:properties)
+                      message.try_call(model, model.class.properties[field_name])
+                    else
+                      # pure Ruby object
+                      message.try_call(model)
+                    end
+        end
         (errors[field_name] ||= []) << message
       end
 
@@ -80,7 +98,7 @@ def each
       end
 
       def empty?
-        entries.empty?
+        @errors.empty?
       end
 
       def method_missing(meth, *args, &block)
@@ -89,7 +107,7 @@ def method_missing(meth, *args, &block)
 
       private
       def errors
-        @errors ||= {}
+        @errors
       end
 
     end # class ValidationErrors

dm-validations/spec/integration/confirmation_validator/confirmation_validator_spec.rb

@@ -12,7 +12,8 @@
 
 describe "reservation with mismatched seats number", :shared => true do
   it "has meaningful error message" do
-    @model.errors.on(:number_of_seats).should include("Number of seats does not match the confirmation")
+    # Proc gets expanded here
+    @model.errors.on(:number_of_seats).should include("Reservation requires confirmation for number_of_seats")
   end
 end
 

dm-validations/spec/integration/confirmation_validator/spec_helper.rb

@@ -29,7 +29,9 @@ class Reservation
         #
 
         validates_is_confirmed :person_name,     :allow_nil => false
-        validates_is_confirmed :number_of_seats, :confirm => :seats_confirmation
+        validates_is_confirmed :number_of_seats, :confirm => :seats_confirmation, :message => Proc.new { |model, property|
+          "%s requires confirmation for %s" % [model.class.name.split("::").last, property.name]
+        }
       end # Reservation
     end # Fixtures
   end # Validate

dm-validations/spec/integration/pure_ruby_objects/plain_old_ruby_object_validation_spec.rb

@@ -15,7 +15,9 @@ class Country
     #
 
     validates_present :name,       :when => [:default, :adding_to_encyclopedia]
-    validates_present :population, :when => :adding_to_encyclopedia
+    validates_present :population, :when => :adding_to_encyclopedia, :message => Proc.new { |record|
+      "population really needs to be specified when adding %s to encyclopedia" % [record.class.name]
+    }
 
     validates_length  :name,       :in => (4..50)
 
@@ -64,6 +66,12 @@ def initialize(name, population = nil)
       @model.should_not be_valid(:adding_to_encyclopedia)
       @model.should_not be_valid_for_adding_to_encyclopedia
     end
+
+    it "has a meaningful error message" do
+      # trigger validation => have errors on the object
+      @model.valid_for_adding_to_encyclopedia?
+      @model.errors.on(:population).should == ["population really needs to be specified when adding PureRubyObjects::Country to encyclopedia"]
+    end
   end
 
 
@@ -96,16 +104,16 @@ def initialize(name, population = nil)
       @model.name = "It"
       @model.valid?
     end
-    
+
     it_should_behave_like "object invalid in default context"
 
     it "has errors on name" do
       @model.errors.on(:name).should_not be_blank
     end
-    
+
     it "is valid in encyclopedia context" do
       @model.should be_valid(:adding_to_encyclopedia)
       @model.should be_valid_for_adding_to_encyclopedia
     end
-  end  
+  end
 end

dm-validations/spec/unit/validation_errors/adding_spec.rb

@@ -4,7 +4,7 @@
 
 describe DataMapper::Validate::ValidationErrors do
   before :all do
-    @model = DataMapper::Validate::ValidationErrors.new
+    @model = DataMapper::Validate::ValidationErrors.new(Object.new)
   end
 
   describe "after first error being added" do

dm-validations/spec/unit/validation_errors/emptiness_spec.rb

@@ -4,7 +4,7 @@
 
 describe DataMapper::Validate::ValidationErrors do
   before :all do
-    @model = DataMapper::Validate::ValidationErrors.new
+    @model = DataMapper::Validate::ValidationErrors.new(Object.new)
   end
 
   describe "initially" do

dm-validations/spec/unit/validation_errors/enumerable_spec.rb

@@ -4,7 +4,7 @@
 
 describe DataMapper::Validate::ValidationErrors do
   before :all do
-    @model = DataMapper::Validate::ValidationErrors.new
+    @model = DataMapper::Validate::ValidationErrors.new(Object.new)
     @model.add(:ip_address, "must have valid format")
     @model.add(:full_name, "can't be blank")
   end