Add support for bounded enumerables

app/helpers/maintenance_tasks/tasks_helper.rb

@@ -7,6 +7,8 @@ module MaintenanceTasks
   #
   # @api private
   module TasksHelper
+    MAX_INCLUSION_ITEMS = 1000
+
     STATUS_COLOURS = {
       "new" => ["is-primary"],
       "enqueued" => ["is-primary is-light"],
@@ -101,10 +103,21 @@ def csv_file_download_path(run)
       )
     end
 
-    # Resolves values covered by the inclusion validator for a task attribute.
-    # Only Arrays are supported.
-    # Procs and lambdas are also supported, but only if they take no arguments and return an Array.
-    # Option types such as Symbols, and Range are not supported and return nil.
+    # Resolves values covered by the inclusion validator for a task attribute,
+    # but only if it can be resolved to an array in a stateless manner.
+    #
+    # Examples of supported constraints:
+    # - Arrays
+    # - Enumerable that can be converted to an Array
+    # - Procs and lambdas, but only if they take no arguments and return a value meeting the requirements above.
+    #
+    # Examples of unsupported constraints, which would return nil:
+    # - Symbols (which would normally resolve to an instance method)
+    # - Procs and lambdas that take an argument (which would be the instance)
+    # - Unbounded ranges (e.g. `1..`)
+    #
+    # If the resulting Array is larger than #MAX_INCLUSION_ITEMS, the method will return nil.
+    # This is meant to make sure the process does not misbehave if the inclusion range is giant or infinite.
     #
     # Returned values are used to populate a dropdown list of options.
     #
@@ -120,6 +133,12 @@ def resolve_inclusion_value(task_class, parameter_name)
 
       in_option = inclusion_validator.options[:in] || inclusion_validator.options[:within]
       in_option = in_option.call if in_option.is_a?(Proc) && in_option.arity.zero?
+
+      if in_option.is_a?(Enumerable)
+        items = in_option.take(MAX_INCLUSION_ITEMS + 1).to_a
+        in_option = items if items.size <= MAX_INCLUSION_ITEMS
+      end
+
       in_option if in_option.is_a?(Array)
     end
 

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

@@ -30,11 +30,15 @@ class ParamsTask < MaintenanceTasks::Task
     attribute :text_integer_attr_proc_arg, :integer
     attribute :text_integer_attr_undefined_symbol, :integer
     attribute :text_integer_attr_unbounded_range, :integer
+    attribute :text_integer_attr_bounded_range, :integer
+    attribute :text_integer_attr_enumerable, :integer
 
     validates_inclusion_of :text_integer_attr_proc_no_arg, in: proc { [100, 200, 300] }, allow_nil: true
     validates_inclusion_of :text_integer_attr_proc_arg, in: proc { |_task| [100, 200, 300] }, allow_nil: true
     validates_inclusion_of :text_integer_attr_undefined_symbol, in: :undefined_symbol, allow_nil: true
     validates_inclusion_of :text_integer_attr_unbounded_range, in: (100..), allow_nil: true
+    validates_inclusion_of :text_integer_attr_bounded_range, in: (100..120), allow_nil: true
+    validates_inclusion_of :text_integer_attr_enumerable, in: (100..120).step(5), allow_nil: true
 
     class << self
       attr_accessor :fast_task

test/helpers/maintenance_tasks/tasks_helper_test.rb

@@ -96,6 +96,8 @@ class TasksHelperTest < ActionView::TestCase
         "integer_dropdown_attr",
         "boolean_dropdown_attr",
         "text_integer_attr_proc_no_arg",
+        "text_integer_attr_bounded_range",
+        "text_integer_attr_enumerable",
       ].each do |attribute|
         assert_match "Select a value", markup(attribute).squish
       end

test/models/maintenance_tasks/task_data_show_test.rb

@@ -93,6 +93,8 @@ class TaskDataShowTest < ActiveSupport::TestCase
           "text_integer_attr_proc_arg",
           "text_integer_attr_undefined_symbol",
           "text_integer_attr_unbounded_range",
+          "text_integer_attr_bounded_range",
+          "text_integer_attr_enumerable",
         ],
         TaskDataShow.new("Maintenance::ParamsTask").parameter_names,
       )

test/system/maintenance_tasks/tasks_test.rb

@@ -128,6 +128,18 @@ class TasksTest < ApplicationSystemTestCase
       integer_dropdown_field_options = integer_dropdown_field.find_all("option").map { |option| option[:value] }
       assert_equal(["", "100", "200", "300"], integer_dropdown_field_options)
 
+      integer_dropdown_field = page.find_field("task[text_integer_attr_bounded_range]")
+      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..120).to_a.map(&:to_s), integer_dropdown_field_options)
+
+      integer_dropdown_field = page.find_field("task[text_integer_attr_enumerable]")
+      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", "105", "110", "115", "120"], 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])