Add support for procs and method calls in inclusion validation dropdown resolution

README.md

@@ -485,6 +485,23 @@ to run. Since arguments are specified in the user interface via text area
 inputs, it’s important to check that they conform to the format your Task
 expects, and to sanitize any inputs if necessary.
 
+#### Validating Task Parameters
+
+Task attributes can be validated using Active Model Validations. Attributes are
+validated before a Task is enqueued.
+
+If an attribute uses an inclusion validator with a supported `in:` option, the
+set of values will be used to populate a dropdown in the user interface. The
+following types are supported:
+
+* Arrays
+* Procs and lambdas that optionally accept the Task instance, and return an Array.
+* Callable objects that receive one argument, the Task instance, and return an Array.
+* Methods that return an Array, called on the Task instance.
+
+For enumerables that don't match the supported types, a text field will be
+rendered instead.
+
 ### Custom cursor columns to improve performance
 
 The [job-iteration gem][job-iteration], on which this gem depends, adds an

app/helpers/maintenance_tasks/tasks_helper.rb

@@ -102,29 +102,53 @@ def csv_file_download_path(run)
     end
 
     # Resolves values covered by the inclusion validator for a task attribute.
-    # Only Arrays are supported, option types such as:
-    # Procs, lambdas, symbols, and Range are not supported and return nil.
+    # Supported option types:
+    # - Arrays
+    # - Procs and lambdas that optionally accept the Task instance, and return an Array.
+    # - Callable objects that receive one argument, the Task instance, and return an Array.
+    # - Methods that return an Array, called on the Task instance.
+    #
+    # Other types are not supported and will return nil.
     #
     # Returned values are used to populate a dropdown list of options.
     #
     # @param task_class [Class<Task>] The task class for which the value needs to be resolved.
     # @param parameter_name [String] The parameter name.
     #
     # @return [Array] value of the resolved inclusion option.
-    def resolve_inclusion_value(task_class, parameter_name)
+    def resolve_inclusion_value(task, parameter_name)
+      task_class = task.class
       inclusion_validator = task_class.validators_on(parameter_name).find do |validator|
         validator.kind == :inclusion
       end
       return unless inclusion_validator
 
       in_option = inclusion_validator.options[:in] || inclusion_validator.options[:within]
-      in_option if in_option.is_a?(Array)
+      resolved_in_option = case in_option
+      when Proc
+        if in_option.arity == 0
+          in_option.call
+        else
+          in_option.call(task)
+        end
+      when Symbol
+        method = task.method(in_option)
+        method.call if method.arity.zero?
+      else
+        if in_option.respond_to?(:call)
+          in_option.call(task)
+        else
+          in_option
+        end
+      end
+
+      resolved_in_option if resolved_in_option.is_a?(Array)
     end
 
     # Return the appropriate field tag for the parameter, based on its type.
     # If the parameter has a `validates_inclusion_of` validator, return a dropdown list of options instead.
     def parameter_field(form_builder, parameter_name)
-      inclusion_values = resolve_inclusion_value(form_builder.object.class, parameter_name)
+      inclusion_values = resolve_inclusion_value(form_builder.object, parameter_name)
       return form_builder.select(parameter_name, inclusion_values, prompt: "Select a value") if inclusion_values
 
       case form_builder.object.class.attribute_types[parameter_name]

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

@@ -1,6 +1,14 @@
 # frozen_string_literal: true
 
 module Maintenance
+  class DropdownOptions
+    class << self
+      def call(_task)
+        [100, 200, 300]
+      end
+    end
+  end
+
   class ParamsTask < MaintenanceTasks::Task
     attribute :post_ids, :string
 
@@ -20,24 +28,31 @@ class ParamsTask < MaintenanceTasks::Task
 
     # Dropdown options with supported scenarios
     attribute :integer_dropdown_attr, :integer
+    attribute :integer_dropdown_attr_proc_no_arg, :integer
+    attribute :integer_dropdown_attr_proc_arg, :integer
+    attribute :integer_dropdown_attr_from_method, :integer
+    attribute :integer_dropdown_attr_callable, :integer
     attribute :boolean_dropdown_attr, :boolean
 
     validates_inclusion_of :integer_dropdown_attr, in: [100, 200, 300], allow_nil: true
+    validates_inclusion_of :integer_dropdown_attr_proc_no_arg, in: proc { [100, 200, 300] }, allow_nil: true
+    validates_inclusion_of :integer_dropdown_attr_proc_arg, in: proc { |_task| [100, 200, 300] }, allow_nil: true
+    validates_inclusion_of :integer_dropdown_attr_from_method, in: :dropdown_attr_options, allow_nil: true
+    validates_inclusion_of :integer_dropdown_attr_callable, in: DropdownOptions, allow_nil: true
     validates_inclusion_of :boolean_dropdown_attr, within: [true, false], allow_nil: true
 
     # Dropdown options with unsupported scenarios
-    attribute :text_integer_attr, :integer
-    attribute :text_integer_attr2, :integer
-    attribute :text_integer_attr3, :integer
-
-    validates_inclusion_of :text_integer_attr, in: proc { [100, 200, 300] }, allow_nil: true
-    validates_inclusion_of :text_integer_attr2, in: :undefined_symbol, allow_nil: true
-    validates_inclusion_of :text_integer_attr3, in: (100..), allow_nil: true
+    attribute :text_integer_attr_unbounded_range, :integer
+    validates_inclusion_of :text_integer_attr_unbounded_range, in: (100..), allow_nil: true
 
     class << self
       attr_accessor :fast_task
     end
 
+    def dropdown_attr_options
+      [100, 200, 300]
+    end
+
     def collection
       Post.where(id: post_ids_array)
     end

test/helpers/maintenance_tasks/tasks_helper_test.rb

@@ -92,13 +92,18 @@ class TasksHelperTest < ActionView::TestCase
     end
 
     test "#resolve_inclusion_value resolves inclusion validator for task attributes" do
-      assert_match "Select a value", markup("integer_dropdown_attr").squish
-
-      assert_match "Select a value", markup("boolean_dropdown_attr").squish
-
-      ["text_integer_attr", "text_integer_attr2", "text_integer_attr3"].each do |text_integer_attr|
-        refute_match "Select a value", markup(text_integer_attr).squish
+      [
+        "integer_dropdown_attr",
+        "boolean_dropdown_attr",
+        "integer_dropdown_attr_proc_no_arg",
+        "integer_dropdown_attr_proc_arg",
+        "integer_dropdown_attr_from_method",
+        "integer_dropdown_attr_callable",
+      ].each do |attribute|
+        assert_match "Select a value", markup(attribute).squish
       end
+
+      refute_match "Select a value", markup("text_integer_attr_unbounded_range").squish
     end
 
     test "#parameter_field adds information about datetime fields when Time.zone_default is not set" do

test/models/maintenance_tasks/task_data_show_test.rb

@@ -88,10 +88,12 @@ class TaskDataShowTest < ActiveSupport::TestCase
           "time_attr",
           "boolean_attr",
           "integer_dropdown_attr",
+          "integer_dropdown_attr_proc_no_arg",
+          "integer_dropdown_attr_proc_arg",
+          "integer_dropdown_attr_from_method",
+          "integer_dropdown_attr_callable",
           "boolean_dropdown_attr",
-          "text_integer_attr",
-          "text_integer_attr2",
-          "text_integer_attr3",
+          "text_integer_attr_unbounded_range",
         ],
         TaskDataShow.new("Maintenance::ParamsTask").parameter_names,
       )

test/system/maintenance_tasks/tasks_test.rb

@@ -117,24 +117,24 @@ class TasksTest < ApplicationSystemTestCase
       assert_equal("input", boolean_field.tag_name)
       assert_equal("checkbox", boolean_field[:type])
 
-      integer_dropdown_field = page.find_field("task[integer_dropdown_attr]")
-      assert_equal("select", integer_dropdown_field.tag_name)
-      assert_equal("select-one", integer_dropdown_field[:type])
-      integer_dropdown_field_options = integer_dropdown_field.find_all("option").map { |option| option[:value] }
-      assert_equal(["", "100", "200", "300"], integer_dropdown_field_options)
-
-      boolean_dropdown_field = page.find_field("task[boolean_dropdown_attr]")
-      assert_equal("select", boolean_dropdown_field.tag_name)
-      assert_equal("select-one", boolean_dropdown_field[:type])
-      boolean_dropdown_field_options = boolean_dropdown_field.find_all("option").map { |option| option[:value] }
-      assert_equal(["", "true", "false"], boolean_dropdown_field_options)
-
-      ["text_integer_attr", "text_integer_attr2", "text_integer_attr3"].each do |text_integer_attr|
-        text_integer_dropdown_field = page.find_field("task[#{text_integer_attr}]")
-        assert_equal("input", text_integer_dropdown_field.tag_name)
-        assert_equal("number", text_integer_dropdown_field[:type])
-        assert_empty(text_integer_dropdown_field[:step])
+      [
+        "integer_dropdown_attr",
+        "integer_dropdown_attr_proc_no_arg",
+        "integer_dropdown_attr_proc_arg",
+        "integer_dropdown_attr_from_method",
+        "integer_dropdown_attr_callable",
+      ].each do |dropdown_integer_attr|
+        integer_dropdown_field = page.find_field("task[#{dropdown_integer_attr}]")
+        assert_equal("select", integer_dropdown_field.tag_name)
+        assert_equal("select-one", integer_dropdown_field[:type])
+        integer_dropdown_field_options = integer_dropdown_field.find_all("option").map { |option| option[:value] }
+        assert_equal(["", "100", "200", "300"], integer_dropdown_field_options)
       end
+
+      text_integer_field = page.find_field("task[text_integer_attr_unbounded_range]")
+      assert_equal("input", text_integer_field.tag_name)
+      assert_equal("number", text_integer_field[:type])
+      assert_empty(text_integer_field[:step])
     end
 
     test "view a Task with multiple pages of Runs" do