Fix to raise NameError via configuration and error message check (#221)

.github/workflows/pr-build.yml

@@ -59,6 +59,8 @@ jobs:
         with:
           ruby-version: ${{ matrix.ruby }}
           bundler-cache: true
+          # @see https://github.com/openstreetmap/openstreetmap-website/issues/4364
+          rubygems: latest
 
       - name: Rubocop Check
         if: ${{ github.event_name == 'pull_request' }}

spec/dummy/app/not_autoloaded_models/broken_product.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class BrokenProduct
+  missing_class_method_called
+end

spec/wallaby-core/lib/wallaby/classifier_spec.rb

@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Wallaby::Classifier do
+  describe '.class_name_of' do
+    subject(:class_name) { described_class.class_name_of(object) }
+
+    context 'when object is class' do
+      let(:object) { Class }
+
+      it { is_expected.to eq('Class') }
+
+      context 'when object is anonymous class' do
+        let(:object) { Class.new }
+
+        it { is_expected.to be_nil }
+      end
+    end
+
+    context 'when object is not a class' do
+      context 'when object is string' do
+        let(:object) { 'Class' }
+
+        it { is_expected.to eq('Class') }
+
+        context 'when object is empty string' do
+          let(:object) { '' }
+
+          it { is_expected.to eq('') }
+        end
+      end
+
+      context 'when object is symbol' do
+        let(:object) { :Class }
+
+        it { is_expected.to eq('Class') }
+      end
+
+      context 'when object is integer' do
+        let(:object) { 1 }
+
+        it { is_expected.to eq('1') }
+      end
+
+      context 'when object is nil' do
+        let(:object) { nil }
+
+        it { is_expected.to be_nil }
+      end
+    end
+  end
+
+  describe '.to_class' do
+    subject(:klass) { described_class.to_class(class_name, raising: raising) }
+
+    let(:raising) { false }
+
+    context 'when class exists' do
+      let(:class_name) { 'Product' }
+
+      it { is_expected.to eq(Product) }
+
+      context 'when class has missing method error' do
+        let(:class_name) { 'BrokenProduct' }
+
+        it { expect { subject }.to raise_error(NameError, "undefined local variable or method `missing_class_method_called' for BrokenProduct:Class") }
+      end
+    end
+
+    context 'when class not exists' do
+      let(:class_name) { 'UnknownProduct' }
+
+      it { is_expected.to be_nil }
+
+      context 'when raising is true' do
+        let(:raising) { true }
+
+        it { expect { subject }.to raise_error(NameError, /uninitialized constant/) }
+      end
+    end
+
+    context 'when class name is empty string' do
+      let(:class_name) { '' }
+
+      it { is_expected.to be_nil }
+    end
+  end
+end

spec/wallaby-core/lib/wallaby/configuration_spec.rb

@@ -9,6 +9,12 @@
       :base_controller, ::ApplicationController, ::ActionController::Base
   end
 
+  describe '#raise_on_name_error' do
+    it_behaves_like \
+      'has attribute with default value',
+      :raise_on_name_error, nil, true
+  end
+
   describe '#security' do
     it 'returns the configuration of security' do
       expect(subject.security).to be_a described_class::Security

wallaby-core/lib/wallaby/classifier.rb

@@ -7,24 +7,32 @@ module Classifier
 
     # Convert Class to String. If not Class, unchanged.
     # @param klass [Object]
-    # @return [String] if klass is a Class
-    # @return [Object] if klass is not a Class
+    # @return [String] if klass is not nil
+    # @return [nil] if klass is nil or klass is an anonymous Class
     def class_name_of(klass)
-      klass.try(:name) || klass || nil
+      klass.is_a?(Class) ? klass.try(:name) : klass.try(:to_s)
     end
 
     # Convert String to Class. If not String, unchanged.
     # @param name [Object]
     # @return [Class] if name is a Class
     # @return [Object] if name is not a String
     # @return [nil] if class cannot be found
-    def to_class(name)
-      return name unless name.is_a? String
+    def to_class(name, raising: Wallaby.configuration.raise_on_name_error)
+      return name unless name.is_a?(String)
+      # blank string will lead to NameError `wrong constant name`
+      return if name.blank?
 
-      # NOTE: DO NOT try to use const_defined? and const_get EVER.
-      # This is Rails, use constantize
+      # NOTE: DO NOT try to use `const_defined?` and `const_get` EVER.
+      # Rails does all the class loading magics using `constantize`
       name.constantize
-    rescue NameError
+    rescue NameError => e
+      raise if raising
+
+      uninitialized = e.message.start_with?('uninitialized constant')
+      raise unless uninitialized
+
+      # block to handle this missing constant, e.g. use a default class or log useful instruction
       yield(name) if block_given?
     end
   end

wallaby-core/lib/wallaby/configuration.rb

@@ -6,6 +6,9 @@ module Wallaby
   class Configuration
     include Classifier
 
+    # @!attribute [w] raise_on_name_error
+    attr_accessor :raise_on_name_error
+
     # @!attribute [w] logger
     attr_writer :logger
 
@@ -101,6 +104,7 @@ def models
       Deprecator.alert 'config.models.presence', from: '0.3.0', alternative: <<~INSTRUCTION
         Please use controller_class.models instead.
       INSTRUCTION
+      @models ||= Models.new
     end
 
     # To globally configure the models that Wallaby should handle.