Added custom_compile setting

Provide an easy way to tell webpacker that we have a custom compile
operation, such as used by react on rails.

Author: justin808

lib/install/config/webpacker.yml

@@ -5,6 +5,7 @@ default: &default
   source_entry_path: packs
   public_output_path: packs
   cache_path: tmp/cache/webpacker
+  custom_compile: false
 
   # Additional paths webpack should lookup modules
   # ['app/assets', 'engine/foo/app/assets']

lib/tasks/webpacker/check_binstubs.rake

@@ -1,7 +1,8 @@
 namespace :webpacker do
   desc "Verifies that bin/webpack & bin/webpack-dev-server are present."
   task :check_binstubs do
-    unless File.exist?("bin/webpack") && File.exist?("bin/webpack-dev-server")
+    unless Webpacker.config.custom_compile? ||
+      (File.exist?("bin/webpack") && File.exist?("bin/webpack-dev-server"))
       $stderr.puts "Webpack binstubs not found.\n"\
            "Have you run rails webpacker:install ?\n"\
            "Make sure the bin directory or binstubs are not included in .gitignore\n"\

lib/tasks/webpacker/verify_install.rake

@@ -3,14 +3,16 @@ require "webpacker/configuration"
 namespace :webpacker do
   desc "Verifies if webpacker is installed"
   task verify_install: [:check_node, :check_yarn, :check_binstubs] do
-    if Webpacker.config.config_path.exist?
-      $stdout.puts "Webpacker is installed 🎉 🍰"
-      $stdout.puts "Using #{Webpacker.config.config_path} file for setting up webpack paths"
-    else
-      $stderr.puts "Configuration config/webpacker.yml file not found. \n"\
+    unless Webpacker.config.custom_compile?
+      if Webpacker.config.config_path.exist?
+        $stdout.puts "Webpacker is installed 🎉 🍰"
+        $stdout.puts "Using #{Webpacker.config.config_path} file for setting up webpack paths"
+      else
+        $stderr.puts "Configuration config/webpacker.yml file not found. \n"\
            "Make sure webpacker:install is run successfully before " \
            "running dependent tasks"
-      exit!
+        exit!
+      end
     end
   end
 end

lib/webpacker/configuration.rb

@@ -17,6 +17,10 @@ def compile?
     fetch(:compile)
   end
 
+  def custom_compile?
+    fetch(:custom_compile)
+  end
+
   def source_path
     root_path.join(fetch(:source_path))
   end

lib/webpacker/manifest.rb

@@ -42,7 +42,7 @@ def find(name)
 
     def handle_missing_entry(name)
       raise Webpacker::Manifest::MissingEntryError,
-        "Can't find #{name} in #{config.public_manifest_path}. Manifest contains: #{@data}"
+        "Can't find #{name} in #{config.public_manifest_path}. Manifest contains:\n#{JSON.pretty_generate(@data)}"
     end
 
     def missing_file_from_manifest_error(bundle_name)

test/manifest_test.rb

@@ -9,8 +9,17 @@ def test_lookup_exception
       error = assert_raises Webpacker::Manifest::MissingEntryError do
         Webpacker.manifest.lookup(asset_file)
       end
+      expected = <<-MSG.strip
+Can't find calendar.js in #{manifest_path}. Manifest contains:
+{
+  "bootstrap.css": "/packs/bootstrap-c38deda30895059837cf.css",
+  "application.css": "/packs/application-dd6b1cd38bfa093df600.css",
+  "bootstrap.js": "/packs/bootstrap-300631c4f0e0f9c865bc.js",
+  "application.js": "/packs/application-k344a6d59eef8632c9d1.js"
+}
+      MSG
 
-      assert_equal "Can't find #{asset_file} in #{manifest_path}. Is webpack still compiling?", error.message
+      assert_equal expected, error.message
     end
   end