DEV: Cleanup legacy asset compilation gems and code (#19177)

We now use Ember CLI (core/plugins) and DiscourseJSProcessor (themes) for all Ember and template compilation. This commit removes the remnants of the legacy Sprockets-based Ember compilation system.

Sprockets, and its DiscourseJSProcess-based Babel transformations, is still in use for a few assets. Ideally that will be removed/replaced in the near future.

Gemfile

@@ -63,15 +63,8 @@ gem 'active_model_serializers', '~> 0.8.3'
 
 gem 'http_accept_language', require: false
 
-# Ember related gems need to be pinned cause they control client side
-# behavior, we will push these versions up when upgrading ember
-gem 'discourse-ember-rails', '0.18.6', require: 'ember-rails'
-gem 'discourse-ember-source', '~> 3.12.2'
-gem 'ember-handlebars-template', '0.8.0'
 gem 'discourse-fonts', require: 'discourse_fonts'
 
-gem 'barber'
-
 gem 'message_bus'
 
 gem 'rails_multisite'

Gemfile.lock

@@ -73,9 +73,6 @@ GEM
       aws-sigv4 (~> 1.1)
     aws-sigv4 (1.5.0)
       aws-eventstream (~> 1, >= 1.0.2)
-    barber (0.12.2)
-      ember-source (>= 1.0, < 3.1)
-      execjs (>= 1.2, < 3)
     better_errors (2.9.1)
       coderay (>= 1.0.0)
       erubi (>= 1.0.0)
@@ -119,14 +116,6 @@ GEM
     diff-lcs (1.5.0)
     diffy (3.4.2)
     digest (3.1.0)
-    discourse-ember-rails (0.18.6)
-      active_model_serializers
-      ember-data-source (>= 1.0.0.beta.5)
-      ember-handlebars-template (>= 0.1.1, < 1.0)
-      ember-source (>= 1.1.0)
-      jquery-rails (>= 1.0.17)
-      railties (>= 3.1)
-    discourse-ember-source (3.12.2.3)
     discourse-fonts (0.0.9)
     discourse-seed-fu (2.3.12)
       activerecord (>= 3.1)
@@ -138,12 +127,6 @@ GEM
     ecma-re-validator (0.4.0)
       regexp_parser (~> 2.2)
     email_reply_trimmer (0.1.13)
-    ember-data-source (3.0.2)
-      ember-source (>= 2, < 3.0)
-    ember-handlebars-template (0.8.0)
-      barber (>= 0.11.0)
-      sprockets (>= 3.3, < 4.1)
-    ember-source (2.18.2)
     erubi (1.11.0)
     excon (0.94.0)
     execjs (2.8.1)
@@ -185,10 +168,6 @@ GEM
     image_size (3.2.0)
     in_threads (1.6.0)
     jmespath (1.6.1)
-    jquery-rails (4.5.1)
-      rails-dom-testing (>= 1, < 3)
-      railties (>= 4.2.0)
-      thor (>= 0.14, < 2.0)
     json (2.6.2)
     json-schema (3.0.0)
       addressable (>= 2.8)
@@ -531,7 +510,6 @@ DEPENDENCIES
   annotate
   aws-sdk-s3
   aws-sdk-sns
-  barber
   better_errors
   binding_of_caller
   bootsnap
@@ -546,13 +524,10 @@ DEPENDENCIES
   css_parser
   diffy
   digest
-  discourse-ember-rails (= 0.18.6)
-  discourse-ember-source (~> 3.12.2)
   discourse-fonts
   discourse-seed-fu
   discourse_dev_assets
   email_reply_trimmer
-  ember-handlebars-template (= 0.8.0)
   excon
   execjs
   fabrication

config/application.rb

@@ -172,18 +172,6 @@ module Discourse
     require 'middleware/discourse_public_exceptions'
     config.exceptions_app = Middleware::DiscoursePublicExceptions.new(Rails.public_path)
 
-    # Our templates shouldn't start with 'discourse/app/templates'
-    config.handlebars.templates_root = {
-      'discourse/app/templates' => '',
-      'admin/addon/templates' => 'admin/templates/',
-      'wizard/addon/templates' => 'wizard/templates/',
-      'select-kit/addon/templates' => 'select-kit/templates/'
-    }
-
-    config.handlebars.raw_template_namespace = "__DISCOURSE_RAW_TEMPLATES"
-    Sprockets.register_mime_type 'text/x-handlebars', extensions: ['.hbr']
-    Sprockets.register_transformer 'text/x-handlebars', 'application/javascript', Ember::Handlebars::Template
-
     require 'discourse_js_processor'
     require 'discourse_sourcemapping_url_processor'
 
@@ -211,11 +199,6 @@ module Discourse
     # our setup does not use rack cache and instead defers to nginx
     config.action_dispatch.rack_cache = nil
 
-    # ember stuff only used for asset precompilation, production variant plays up
-    config.ember.variant = :development
-    config.ember.ember_location = "#{Rails.root}/vendor/assets/javascripts/production/ember.js"
-    config.ember.handlebars_location = "#{Rails.root}/vendor/assets/javascripts/handlebars.js"
-
     require 'auth'
 
     if GlobalSetting.relative_url_root.present?

config/cloud/cloud66/files/production.rb

@@ -43,9 +43,6 @@ Discourse::Application.configure do
   # Send deprecation notices to registered listeners
   config.active_support.deprecation = :notify
 
-  # this will cause all handlebars templates to be pre-compiles, making your page faster
-  config.handlebars.precompile = true
-
   # this setting enables rack_cache so it caches various requests in redis
   config.enable_rack_cache = true
 

config/environments/development.rb

@@ -40,8 +40,6 @@ Discourse::Application.configure do
   config.active_record.migration_error = :page_load
   config.watchable_dirs['lib'] = [:rb]
 
-  config.handlebars.precompile = true
-
   # we recommend you use mailhog https://github.com/mailhog/MailHog
   config.action_mailer.smtp_settings = { address: "localhost", port: 1025 }
 

config/environments/production.rb

@@ -52,9 +52,6 @@ Discourse::Application.configure do
   # Send deprecation notices to registered listeners
   config.active_support.deprecation = :notify
 
-  # this will cause all handlebars templates to be pre-compiled, making your page faster
-  config.handlebars.precompile = true
-
   # allows developers to use mini profiler
   config.load_mini_profiler = GlobalSetting.load_mini_profiler
 

config/environments/profile.rb

@@ -35,9 +35,6 @@ Discourse::Application.configure do
   # Send deprecation notices to registered listeners
   config.active_support.deprecation = :notify
 
-  # precompile handlebar assets
-  config.handlebars.precompile = true
-
   # allows users to use mini profiler
   config.load_mini_profiler = false
 

config/environments/test.rb

@@ -40,7 +40,6 @@ Discourse::Application.configure do
 
   # lower iteration count for test
   config.pbkdf2_iterations = 10
-  config.ember.variant = :development
 
   config.assets.compile = true
   config.assets.digest = false

lib/freedom_patches/barber_ember_precompiler.rb

@@ -1,36 +0,0 @@
-# frozen_string_literal: true
-
-# Eventually we aim to move away from using Barber to precompile assets.
-# These overrides unblock us moving to more recent ember versions in the meantime
-
-module BarberEmberPrecompilerFreedomPatch
-  # Use the template compiler JS from node_modules
-  def ember_template_precompiler
-    @ember ||= File.new("app/assets/javascripts/node_modules/ember-source/dist/ember-template-compiler.js")
-  end
-
-  # Apply a couple of extra shims for more recent ember-template-compilers
-  def source_fixes
-    shims = super
-
-    shims << <<~JS
-      module = {exports:{}}
-
-      console = {
-        log: function(){},
-        warn: function(){},
-        error: function(){}
-      };
-    JS
-
-    shims
-  end
-
-  # Recent ember-template-compilers fail if `option` is null
-  def compile(template, options = nil)
-    options = {} if options.nil?
-    super(template, options)
-  end
-end
-
-Barber::Ember::Precompiler.prepend(BarberEmberPrecompilerFreedomPatch)

lib/freedom_patches/ember_handlebars.rb

@@ -1,15 +0,0 @@
-# frozen_string_literal: true
-
-class Ember::Handlebars::Template
-
-  # TODO: Remove this after we move to Ember CLI
-  def template_path(path, config)
-    root = config.templates_root
-
-    config.templates_root.each do |k, v|
-      path = path.sub(/#{Regexp.quote(k)}\//, v)
-    end
-
-    path.split('/').join(config.templates_path_separator)
-  end
-end

lib/freedom_patches/raw_handlebars.rb

@@ -1,141 +0,0 @@
-# frozen_string_literal: true
-
-# barber patches to re-route raw compilation via ember compat handlebars
-
-class Barber::Precompiler
-  def sources
-    [File.open("#{Rails.root}/app/assets/javascripts/node_modules/handlebars/dist/handlebars.js"),
-     precompiler]
-  end
-
-  def precompiler
-    if !@precompiler
-      loader = File.read("#{Rails.root}/app/assets/javascripts/node_modules/loader.js/dist/loader/loader.js")
-      source = File.read("#{Rails.root}/app/assets/javascripts/discourse-common/addon/lib/raw-handlebars.js")
-
-      transpiled = DiscourseJsProcessor.transpile(source, "#{Rails.root}/app/assets/javascripts/", "discourse-common/lib/raw-handlebars")
-
-      @precompiler = StringIO.new <<~JS
-        let __RawHandlebars;
-
-        (function(){
-          #{loader}
-          define("handlebars", ["exports"], function(exports){ exports.default = Handlebars; })
-          #{transpiled}
-          __RawHandlebars = require("discourse-common/lib/raw-handlebars").default;
-        })()
-
-        Barber = {
-          precompile: function(string) {
-            return __RawHandlebars.precompile(string, false).toString();
-          }
-        };
-      JS
-
-    end
-
-    @precompiler
-  end
-end
-
-module Discourse
-  module Ember
-    module Handlebars
-      module Helper
-        def precompile_handlebars(string, input = nil)
-          "requirejs('discourse-common/lib/raw-handlebars').template(#{Barber::Precompiler.compile(string)});"
-        end
-
-        def compile_handlebars(string, input = nil)
-          "requirejs('discourse-common/lib/raw-handlebars').compile(#{indent(string).inspect});"
-        end
-      end
-    end
-  end
-end
-
-class Ember::Handlebars::Template
-  prepend Discourse::Ember::Handlebars::Helper
-
-  def path_for(module_name, config)
-    # We need this for backward-compatibility reasons.
-    # Plugins may not have an app subdirectory.
-    template_path(module_name, config).inspect.gsub('discourse/templates/', '')
-  end
-
-  def global_template_target(namespace, module_name, config)
-    "#{namespace}[#{path_for(module_name, config)}]"
-  end
-
-  def call(input)
-    data = input[:data]
-    filename = input[:filename]
-
-    raw = handlebars?(filename)
-
-    if raw
-      template = data
-    else
-      template = mustache_to_handlebars(filename, data)
-    end
-
-    template_name = input[:name]
-
-    module_name =
-      case config.output_type
-      when :amd
-        amd_template_target(config.amd_namespace, template_name)
-      when :global
-        template_path(template_name, config)
-      else
-        raise "Unsupported `output_type`: #{config.output_type}"
-      end
-
-    meta = meta_supported? ? { moduleName: module_name } : false
-
-    if config.precompile
-      if raw
-        template = precompile_handlebars(template, input)
-      else
-        template = precompile_ember_handlebars(template, config.ember_template, input, meta)
-      end
-    else
-      if raw
-        template = compile_handlebars(data)
-      else
-        template = compile_ember_handlebars(template, config.ember_template, meta)
-      end
-    end
-
-    case config.output_type
-    when :amd
-      "define('#{module_name}', ['exports'], function(__exports__){ __exports__['default'] = #{template} });"
-    when :global
-      if raw
-        return <<~JS
-          var __t = #{template};
-          requirejs('discourse-common/lib/raw-templates').addRawTemplate(#{path_for(template_name, config)}, __t);
-        JS
-      end
-
-      target = global_template_target('Ember.TEMPLATES', template_name, config)
-      "#{target} = #{template}\n"
-    else
-      raise "Unsupported `output_type`: #{config.output_type}"
-    end
-  end
-
-  # FIXME: Previously, ember-handlebars-templates uses the logical path which incorrectly
-  # returned paths with the `.raw` extension and our code is depending on the `.raw`
-  # to find the right template to use.
-  def actual_name(input)
-    actual_name = input[:name]
-    input[:filename].include?('.raw') ? "#{actual_name}.raw" : actual_name
-  end
-
-  private
-
-  def handlebars?(filename)
-    filename.to_s =~ /\.raw\.(handlebars|hjs|hbs)/ || filename.to_s.ends_with?(".hbr") || filename.to_s.ends_with?(".hbr.erb")
-  end
-end

script/compile_hbs.rb

@@ -1,26 +0,0 @@
-# frozen_string_literal: true
-
-ctx = MiniRacer::Context.new(timeout: 15000)
-ctx.eval("var self = this; #{File.read("#{Rails.root}/vendor/assets/javascripts/babel.js")}")
-ctx.eval(File.read(Ember::Source.bundled_path_for('ember-template-compiler.js')))
-ctx.eval("module = {}; exports = {};")
-ctx.attach("rails.logger.info", proc { |err| puts(">> #{err.to_s}") })
-ctx.attach("rails.logger.error", proc { |err| puts(">> #{err.to_s}") })
-ctx.eval <<JS
-console = {
-  prefix: "",
-  log: function(msg){ rails.logger.info(console.prefix + msg); },
-  error: function(msg){ rails.logger.error(console.prefix + msg); }
-}
-
-JS
-source = File.read("#{Rails.root}/lib/javascripts/widget-hbs-compiler.js")
-js_source = ::JSON.generate(source, quirks_mode: true)
-js = ctx.eval("Babel.transform(#{js_source}, { ast: false, plugins: ['check-es2015-constants', 'transform-es2015-arrow-functions', 'transform-es2015-block-scoped-functions', 'transform-es2015-block-scoping', 'transform-es2015-classes', 'transform-es2015-computed-properties', 'transform-es2015-destructuring', 'transform-es2015-duplicate-keys', 'transform-es2015-for-of', 'transform-es2015-function-name', 'transform-es2015-literals', 'transform-es2015-object-super', 'transform-es2015-parameters', 'transform-es2015-shorthand-properties', 'transform-es2015-spread', 'transform-es2015-sticky-regex', 'transform-es2015-template-literals', 'transform-es2015-typeof-symbol', 'transform-es2015-unicode-regex'] }).code")
-ctx.eval(js)
-
-if ARGV[0].present?
-  source = File.read(ARGV[0])
-  js_source = ::JSON.generate(source, quirks_mode: true)
-  puts ctx.eval("exports.compile(#{js_source})")
-end

script/test_hbs_compiler.rb

@@ -1,31 +0,0 @@
-# frozen_string_literal: true
-
-template = <<~HBS
-  {{attach widget="wat" attrs=(hash test="abc" text=(i18n "hello" count=attrs.wat))}}
-  {{action-link action="undo" className="undo" text=(i18n (concat "post.actions.undo." attrs.action))}}
-  {{actions-summary-item attrs=as}}
-  {{attach widget="actions-summary-item" attrs=as}}
-  {{testing value="hello"}}
-  {{date "today"}}
-HBS
-
-ctx = MiniRacer::Context.new(timeout: 15000)
-ctx.eval("var self = this; #{File.read("#{Rails.root}/vendor/assets/javascripts/babel.js")}")
-ctx.eval(File.read(Ember::Source.bundled_path_for('ember-template-compiler.js')))
-ctx.eval("module = {}; exports = {};")
-ctx.attach("rails.logger.info", proc { |err| puts(err.to_s) })
-ctx.attach("rails.logger.error", proc { |err| puts(err.to_s) })
-ctx.eval <<JS
-console = {
-  prefix: "",
-  log: function(msg){ rails.logger.info(console.prefix + msg); },
-  error: function(msg){ rails.logger.error(console.prefix + msg); }
-}
-
-JS
-source = File.read("#{Rails.root}/lib/javascripts/widget-hbs-compiler.js")
-ctx.eval(source)
-
-js_source = ::JSON.generate(template, quirks_mode: true)
-
-puts ctx.eval("exports.compile(#{js_source})")