ActiveModel types should only cast and not validate

README.md

@@ -230,19 +230,21 @@ expects, and to sanitize any inputs if necessary.
 The gem provides custom ActiveModel::Type::Value objects for complex parameter
 types:
 
-- `MaintenanceTasks::Parameters::IntegerArrayType`: Accepts a comma-delimited
-string of integers and turns it into an array of integers.
-- `MaintenanceTasks::Parameters::StringArrayType`: Accepts an alphanumeric,
-comma-delimited string and turns it into an array of strings.
+- `IntegerArrayType`: Accepts a comma-delimited string of integers and turns it
+into an array of integers.
+- `StringArrayType`: Accepts an alphanumeric, comma-delimited string and turns
+it into an array of strings.
 
-If you use one of these types for a parameter in your Task, the input will be
-validated automatically and typecast appropriately.
+If you use one of these types for a parameter in your Task, your input will be
+coerced appropriately. **You may still want write validations for your input,
+as type coercion is fairly lax. For example, if you input "xyz" for an
+`IntegerArrayType` parameter, it will be cast to `[0]`.**
 
 ```ruby
 # app/tasks/maintenance/update_posts_via_params_task.rb
 module Maintenance
   class UpdatePostsViaParamsTask < MaintenanceTasks::Task
-    attribute :post_ids, MaintenanceTasks::Parameters::IntegerArrayType.new
+    attribute :post_ids, IntegerArrayType.new
     validates :post_ids, presence: true
 
     def collection

app/controllers/maintenance_tasks/tasks_controller.rb

@@ -33,11 +33,11 @@ def run
       redirect_to(task_path(task))
     rescue ActiveRecord::RecordInvalid => error
       redirect_to(task_path(error.record.task_name), alert: error.message)
-    rescue Runner::EnqueuingError => error
-      redirect_to(task_path(error.run.task_name), alert: error.message)
-    rescue ActiveRecord::ValueTooLong, Parameters::TypeError => error
+    rescue ActiveRecord::ValueTooLong => error
       task_name = params.fetch(:id)
       redirect_to(task_path(task_name), alert: error.message)
+    rescue Runner::EnqueuingError => error
+      redirect_to(task_path(error.run.task_name), alert: error.message)
     end
 
     private

app/models/maintenance_tasks/parameters/integer_array_type.rb → app/models/maintenance_tasks/task/integer_array_type.rb

@@ -1,31 +1,18 @@
 # frozen_string_literal: true
 module MaintenanceTasks
-  module Parameters
+  class Task
     # Type class representing an array of integers. Tasks using the Attributes
     # API for parameter support can use this class to turn input from the UI
     # into an array of integers within their Task.
     class IntegerArrayType < ActiveModel::Type::Value
-      # Casts string from form input field to an array of integers after
-      # validating that the input is correct.
+      # Casts string from form input field to an array of integers.
       #
       # @param input [String] the value to cast to an array of integers.
       # @return [Array<Integer>] the data cast as an array of integers.
       def cast(input)
         return unless input.present?
-
-        validate_input(input)
         input.split(",").map(&:to_i)
       end
-
-      private
-
-      def validate_input(input)
-        unless /\A(\s?\d+\s?(,\s?\d+\s?)*\s?)\z/.match?(input)
-          error_message = "#{self.class} expects a " \
-            "comma-delimited string of integers. Input received: #{input}"
-          raise TypeError, error_message
-        end
-      end
     end
   end
 end

app/models/maintenance_tasks/parameters/string_array_type.rb → app/models/maintenance_tasks/task/string_array_type.rb

@@ -1,31 +1,18 @@
 # frozen_string_literal: true
 module MaintenanceTasks
-  module Parameters
+  class Task
     # Type class representing an array of strings. Tasks using the Attributes
     # API for parameter support can use this class to turn input from the UI
     # into an array of strings within their Task.
     class StringArrayType < ActiveModel::Type::Value
-      # Casts string from form input field to an array of strings after
-      # validating that the input is correct.
+      # Casts string from form input field to an array of strings.
       #
       # @param input [String] the value to cast to an array of strings.
       # @return [Array<Integer>] the data cast as an array of strings.
       def cast(input)
         return unless input.present?
-
-        validate_input(input)
         input.split(",")
       end
-
-      private
-
-      def validate_input(input)
-        unless /\A(\s?\w+\s?(,\s?\w+\s?)*)\z/.match?(input)
-          error_message = "#{self.class} expects alphanumeric, "\
-            "comma-delimited string. Input received: #{input}"
-          raise TypeError, error_message
-        end
-      end
     end
   end
 end

test/dummy/app/tasks/maintenance/params_task.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 module Maintenance
   class ParamsTask < MaintenanceTasks::Task
-    attribute :post_ids, MaintenanceTasks::Parameters::IntegerArrayType.new
+    attribute :post_ids, IntegerArrayType.new
     validates :post_ids, presence: true
 
     class << self

test/models/maintenance_tasks/run_test.rb

@@ -315,16 +315,6 @@ class RunTest < ActiveSupport::TestCase
       assert_equal [1, 2, 3], run.task.post_ids
     end
 
-    test "#validate_task_arguments raises if casting arguments to custom parameter value type fails" do
-      run = Run.new(
-        task_name: "Maintenance::ParamsTask",
-        arguments: { post_ids: "xyz" }
-      )
-      assert_raises MaintenanceTasks::Parameters::TypeError do
-        run.validate_task_arguments
-      end
-    end
-
     private
 
     def count_uncached_queries(&block)

test/models/maintenance_tasks/parameters/integer_array_type_test.rb → test/models/maintenance_tasks/task/integer_array_type_test.rb

@@ -2,7 +2,7 @@
 require "test_helper"
 
 module MaintenanceTasks
-  module Parameters
+  class Task
     class IntegerArrayTypeTest < ActiveSupport::TestCase
       test "#cast returns nil if input not present" do
         assert_nil IntegerArrayType.new.cast("")
@@ -16,17 +16,8 @@ class IntegerArrayTypeTest < ActiveSupport::TestCase
         assert_equal [123, 456, 78], IntegerArrayType.new.cast("123 ,456, 78 ")
       end
 
-      test "#cast raises if input is not valid" do
-        input = "abc"
-        error = assert_raises(TypeError) do
-          IntegerArrayType.new.cast(input)
-        end
-
-        expected_error_message = <<~MSG.squish
-          MaintenanceTasks::Parameters::IntegerArrayType expects a
-          comma-delimited string of integers. Input received: #{input}
-        MSG
-        assert_equal(expected_error_message, error.message)
+      test "#cast handles non-integer input" do
+        assert_equal [0], IntegerArrayType.new.cast("abc")
       end
     end
   end

test/models/maintenance_tasks/task/string_array_type_test.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+require "test_helper"
+
+module MaintenanceTasks
+  class Task
+    class StringArrayTypeTest < ActiveSupport::TestCase
+      test "#cast returns nil if input not present" do
+        assert_nil StringArrayType.new.cast("")
+      end
+
+      test "#cast converts string to array of strings" do
+        assert_equal ["abc", "def"], StringArrayType.new.cast("abc,def")
+      end
+    end
+  end
+end

test/system/maintenance_tasks/runs_test.rb

@@ -57,20 +57,6 @@ class RunsTest < ApplicationSystemTestCase
       assert_text alert_text
     end
 
-    test "errors for Task with arguments using custom parameter types shown" do
-      visit maintenance_tasks_path
-
-      click_on("Maintenance::ParamsTask")
-      fill_in("_task_arguments_post_ids", with: "xyz")
-      click_on "Run"
-
-      alert_text = <<~MSG.squish
-        MaintenanceTasks::Parameters::IntegerArrayType expects
-        a comma-delimited string of integers. Input received: xyz
-      MSG
-      assert_text alert_text
-    end
-
     test "download the CSV attached to a run for a CSV Task" do
       visit(maintenance_tasks_path)