Expose allowed attribute keys

lib/canvas/validators/schema_attribute.rb

@@ -44,6 +44,12 @@ class SchemaAttribute
 
       attr_reader :attribute, :custom_types, :errors, :additional_reserved_names
 
+      class << self
+        def permitted_keys
+          VALIDATORS.flat_map { |_, validator| validator.new({}).permitted_keys }.uniq
+        end
+      end
+
       def initialize(attribute:, custom_types: [], additional_reserved_names: [])
         @attribute = attribute
         @custom_types = custom_types

lib/canvas/validators/schema_attributes/base.rb

@@ -22,6 +22,10 @@ def validate
             ensure_keys_are_correct_types
         end
 
+        def permitted_keys
+          permitted_schema.keys
+        end
+
         private
 
         # The base keys required for this attribute to be valid and their
@@ -59,7 +63,7 @@ def optional_keys
           }
         end
 
-        def all_permitted_keys
+        def permitted_schema
           required_keys.merge(optional_keys)
         end
 
@@ -72,15 +76,15 @@ def ensure_has_required_keys
         end
 
         def ensure_no_unrecognized_keys
-          unrecognized_keys = attribute.keys - all_permitted_keys.keys
+          unrecognized_keys = attribute.keys - permitted_schema.keys
           return true if unrecognized_keys.empty?
 
           @errors << "Unrecognized keys: #{unrecognized_keys.join(', ')}"
           false
         end
 
         def ensure_keys_are_correct_types
-          all_permitted_keys.each do |key, expected|
+          permitted_schema.each do |key, expected|
             if expected.is_a?(Class)
               if attribute.key?(key) && !attribute[key].is_a?(expected)
                 actual = attribute[key].class.name

lib/canvas/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Canvas
-  VERSION = "3.4.0"
+  VERSION = "3.5.0"
 end

spec/lib/canvas/validators/schema_attribute_spec.rb

@@ -13,6 +13,11 @@
     end
   end
 
+  it "exposes all keys permitted to be in attribute schemas, in the order of validators" do
+    expect(described_class.permitted_keys)
+      .to eq(%w[name type default array label hint group only unit options min max step only_from])
+  end
+
   describe "#validate" do
     context "when the attribute has only required keys" do
       let(:attribute) {

spec/lib/canvas/validators/schema_attributes/base_spec.rb

@@ -5,6 +5,25 @@
     Canvas::Validator::SchemaAttribute::Base.new(attribute)
   }
 
+  describe "#permitted_keys" do
+    let(:attribute) { {} }
+    let(:common_attribute_keys) { %w[name type default array label hint group] }
+
+    it "exposes all common permitted keys" do
+      expect(validator.permitted_keys).to eq(common_attribute_keys)
+    end
+
+    it "exposes all extra optional and required keys for subclassed attributes" do
+      class NewAttribute < described_class
+        private
+        def required_keys = super.merge("requiredkey" => String)
+        def optional_keys = super.merge("optionalkey" => String)
+      end
+
+      expect(NewAttribute.new(attribute).permitted_keys).to match_array(common_attribute_keys + %w[requiredkey optionalkey])
+    end
+  end
+
   describe "#validate" do
     context "when attribute is valid" do
       let(:attribute) {