feat: Improved error message for build errors

lib/proscenium/builder.rb

@@ -46,12 +46,17 @@ module Request
     end
 
     class BuildError < StandardError
-      attr_reader :error, :path
+      attr_reader :error
 
-      def initialize(path, error)
-        error = Oj.load(error, mode: :strict).deep_transform_keys(&:underscore)
+      def initialize(error)
+        @error = Oj.load(error, mode: :strict).deep_transform_keys(&:underscore)
 
-        super "Failed to build '#{path}' -- #{error['text']}"
+        msg = @error['text']
+        if (location = @error['location'])
+          msg << " at #{location['file']}:#{location['line']}:#{location['column']}"
+        end
+
+        super msg
       end
     end
 
@@ -86,7 +91,7 @@ def build(path) # rubocop:disable Metrics/AbcSize
                                engines.to_json,
                                Proscenium.config.debug)
 
-        raise BuildError.new(path, result[:response]) unless result[:success]
+        raise BuildError, result[:response] unless result[:success]
 
         result[:response]
       end

lib/proscenium/middleware/esbuild.rb

@@ -20,9 +20,9 @@ def initialize(args)
       end
 
       def attempt
-        render_response Proscenium::Builder.build(path_to_build, root: Rails.root.to_s,
-                                                                 base_url: @request.base_url)
-      rescue Proscenium::Builder::CompileError => e
+        render_response Builder.build(path_to_build, root: Rails.root.to_s,
+                                                     base_url: @request.base_url)
+      rescue Builder::CompileError => e
         raise self.class::CompileError, { file: @request.fullpath, detail: e.message }, caller
       end
     end

lib/proscenium/monkey.rb

@@ -3,6 +3,14 @@
 module Proscenium
   # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
   module Monkey
+    module DebugView
+      def initialize(assigns)
+        paths = [RESCUES_TEMPLATE_PATH, Rails.root.join('lib', 'templates').to_s]
+        lookup_context = ActionView::LookupContext.new(paths)
+        super(lookup_context, assigns, nil)
+      end
+    end
+
     module TemplateRenderer
       private
 

lib/proscenium/railtie.rb

@@ -41,13 +41,17 @@ class Railtie < ::Rails::Engine
     #   end
     config.proscenium.engines = Set.new
 
+    config.action_dispatch.rescue_templates = {
+      'Proscenium::Builder::BuildError' => 'build_error'
+    }
+
     initializer 'proscenium.middleware' do |app|
       app.middleware.insert_after ActionDispatch::Static, Middleware
       # app.middleware.insert_after ActionDispatch::Static, Rack::ETag, 'no-cache'
       # app.middleware.insert_after ActionDispatch::Static, Rack::ConditionalGet
     end
 
-    initializer 'proscenium.monkey_views' do
+    initializer 'proscenium.monkey_patches' do
       ActiveSupport.on_load(:action_view) do
         ActionView::TemplateRenderer.prepend Monkey::TemplateRenderer
         ActionView::PartialRenderer.prepend Monkey::PartialRenderer
@@ -65,3 +69,13 @@ class Railtie < ::Rails::Engine
     end
   end
 end
+
+# Monkey path ActionDispatch::DebugView to use our custom error template on BuildError exceptions.
+class ActionDispatch::DebugView
+  def initialize(assigns)
+    paths = [RESCUES_TEMPLATE_PATH,
+             Proscenium::Railtie.root.join('lib', 'proscenium', 'templates').to_s]
+    lookup_context = ActionView::LookupContext.new(paths)
+    super(lookup_context, assigns, nil)
+  end
+end

lib/proscenium/templates/rescues/build_error.html.erb

@@ -0,0 +1,27 @@
+<header>
+  <h1>
+    <%= @exception.class.to_s %>
+  </h1>
+</header>
+
+<main role="main" id="container">
+  <%= render "rescues/message_and_suggestions", exception: @exception %>
+
+  <% if @exception.error['location'] %>
+    <div class="source">
+      <div class="data">
+<pre>
+
+    <%= @exception.error['location']['file'] %>:<%= @exception.error['location']['line'] %>:<%= @exception.error['location']['column'] %>
+
+<%= @exception.error['location']['line'].to_s.rjust 5 %> │    <%= @exception.error['location']['line_text'] %>
+      │    <%= (@exception.error['location']['length'] > 1 ? "~" * @exception.error['location']['length'] : "^").rjust(@exception.error['location']['column'] + @exception.error['location']['length']) %>
+<%- if @exception.error['location']['suggestion'].present? -%>    + │    <%= @exception.error['location']['suggestion'].rjust(@exception.error['location']['column'] + 1) %>
+<% else %> <%- end -%>
+</pre>
+      </div>
+    </div>
+  <% end %>
+
+  <%= render template: "rescues/_request_and_response" %>
+</main>

test/proscenium/builder.rb

@@ -10,9 +10,9 @@ def before
   with '.build' do
     it 'builds multiple files' do
       expect(subject.build('lib/code_splitting/son.js;lib/code_splitting/daughter.js')).to be == %(
-      lib/code_splitting/son.js::public/assets/lib/code_splitting/son$LAGMAD6O$.js;
-      lib/code_splitting/daughter.js::public/assets/lib/code_splitting/daughter$7JJ2HGHC$.js
-    ).gsub(/[[:space:]]/, '')
+        lib/code_splitting/son.js::public/assets/lib/code_splitting/son$LAGMAD6O$.js;
+        lib/code_splitting/daughter.js::public/assets/lib/code_splitting/daughter$7JJ2HGHC$.js
+      ).gsub(/[[:space:]]/, '')
     end
 
     it 'replaces NODE_ENV and RAILS_ENV' do
@@ -33,7 +33,7 @@ def before
         expect do
           subject.build('unknown.js')
         end.to raise_exception(Proscenium::Builder::BuildError,
-                               message: be == "Failed to build 'unknown.js' -- Could not resolve \"unknown.js\"")
+                               message: be == 'Could not resolve "unknown.js"')
       end
     end
   end