Ensuring version is set earlier in instantiation

app/services/iiif_print/manifest_builder_service_behavior.rb

@@ -4,12 +4,13 @@ def initialize(*args,
                    version: IiifPrint.config.default_iiif_manifest_version,
                    iiif_manifest_factory: iiif_manifest_factory_for(version),
                    &block)
-      super(*args, iiif_manifest_factory: iiif_manifest_factory, &block)
+      # Ensure we're setting the version before we go any further.
       @version = version.to_i
       @child_works = nil
+      super(*args, iiif_manifest_factory: iiif_manifest_factory, &block)
     end
 
-    attr_reader :child_works
+    attr_reader :child_works, :version
 
     def manifest_for(presenter:)
       @child_works = get_solr_hits(member_ids_for(presenter))

lib/iiif_print/configuration.rb

@@ -44,7 +44,7 @@ def excluded_model_name_solr_field_key
 
     attr_writer :default_iiif_manifest_version
     def default_iiif_manifest_version
-      @default_iiif_manifest_version || 2
+      @default_iiif_manifest_version.presence || 2
     end
 
     attr_writer :metadata_fields

spec/iiif_print/configuration_spec.rb

@@ -64,4 +64,24 @@
         .to("-l esperanto")
     end
   end
+
+  describe '#default_iiif_manifest_version' do
+    subject { config.default_iiif_manifest_version }
+
+    context 'default' do
+      it { is_expected.to eq 2 }
+    end
+
+    context 'when set to empty' do
+      before { config.default_iiif_manifest_version = '' }
+      it { is_expected.to eq 2 }
+    end
+
+    it 'can be set' do
+      expect { config.default_iiif_manifest_version = 3 }
+        .to change(config, :default_iiif_manifest_version)
+        .from(2)
+        .to(3)
+    end
+  end
 end

spec/services/iiif_print/manifest_builder_service_behavior_spec.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+RSpec.describe IiifPrint::ManifestBuilderServiceBehavior do
+  context '#initialize' do
+    it 'uses defaults to set the version' do
+      builder_service = Hyrax::ManifestBuilderService.new
+      expect(builder_service.manifest_factory).to eq(::IIIFManifest::ManifestFactory)
+      expect(builder_service.version).to eq(IiifPrint.config.default_iiif_manifest_version)
+    end
+
+    it 'allows version overrides' do
+      # This in part verifies the expected interaction of the version as a parameter being picked up
+      # by another parameter.
+      builder_service = Hyrax::ManifestBuilderService.new(version: 3)
+      expect(builder_service.manifest_factory).to eq(::IIIFManifest::V3::ManifestFactory)
+      expect(builder_service.version).to eq(3)
+    end
+  end
+end