Merge branch 'enable-webpack-code-splitting' into 'master'

Enable webpack code splitting

Closes #32989

See merge request !12032

15 files changed, 137 insertions, 69 deletions

diff --git a/.eslintrc b/.eslintrc
index 73cd7ecf66d..c72a5e0335b 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -11,6 +11,7 @@
     "gon": false,
     "localStorage": false
   },
+  "parser": "babel-eslint",
   "plugins": [
     "filenames",
     "import",
diff --git a/app/assets/javascripts/awards_handler.js b/app/assets/javascripts/awards_handler.js
index c34d80f0601..18cd04b176a 100644
--- a/app/assets/javascripts/awards_handler.js
+++ b/app/assets/javascripts/awards_handler.js
@@ -2,7 +2,6 @@
 /* global Flash */
 
 import Cookies from 'js-cookie';
-import * as Emoji from './emoji';
 
 const animationEndEventString = 'animationend webkitAnimationEnd MSAnimationEnd oAnimationEnd';
 const transitionEndEventString = 'transitionend webkitTransitionEnd oTransitionEnd MSTransitionEnd';
@@ -24,27 +23,9 @@ const categoryLabelMap = {
   flags: 'Flags',
 };
 
-function renderCategory(name, emojiList, opts = {}) {
-  return `
-    <h5 class="emoji-menu-title">
-      ${name}
-    </h5>
-    <ul class="clearfix emoji-menu-list ${opts.menuListClass || ''}">
-      ${emojiList.map(emojiName => `
-        <li class="emoji-menu-list-item">
-          <button class="emoji-menu-btn text-center js-emoji-btn" type="button">
-            ${Emoji.glEmojiTag(emojiName, {
-              sprite: true,
-            })}
-          </button>
-        </li>
-      `).join('\n')}
-    </ul>
-  `;
-}
-
-export default class AwardsHandler {
-  constructor() {
+class AwardsHandler {
+  constructor(emoji) {
+    this.emoji = emoji;
     this.eventListeners = [];
     // If the user shows intent let's pre-build the menu
     this.registerEventListener('one', $(document), 'mouseenter focus', '.js-add-award', 'mouseenter focus', () => {
@@ -78,10 +59,10 @@ export default class AwardsHandler {
       const $target = $(e.currentTarget);
       const $glEmojiElement = $target.find('gl-emoji');
       const $spriteIconElement = $target.find('.icon');
-      const emoji = ($glEmojiElement.length ? $glEmojiElement : $spriteIconElement).data('name');
+      const emojiName = ($glEmojiElement.length ? $glEmojiElement : $spriteIconElement).data('name');
 
       $target.closest('.js-awards-block').addClass('current');
-      this.addAward(this.getVotesBlock(), this.getAwardUrl(), emoji);
+      this.addAward(this.getVotesBlock(), this.getAwardUrl(), emojiName);
     });
   }
 
@@ -139,16 +120,16 @@ export default class AwardsHandler {
     this.isCreatingEmojiMenu = true;
 
     // Render the first category
-    const categoryMap = Emoji.getEmojiCategoryMap();
+    const categoryMap = this.emoji.getEmojiCategoryMap();
     const categoryNameKey = Object.keys(categoryMap)[0];
     const emojisInCategory = categoryMap[categoryNameKey];
-    const firstCategory = renderCategory(categoryLabelMap[categoryNameKey], emojisInCategory);
+    const firstCategory = this.renderCategory(categoryLabelMap[categoryNameKey], emojisInCategory);
 
     // Render the frequently used
     const frequentlyUsedEmojis = this.getFrequentlyUsedEmojis();
     let frequentlyUsedCatgegory = '';
     if (frequentlyUsedEmojis.length > 0) {
-      frequentlyUsedCatgegory = renderCategory('Frequently used', frequentlyUsedEmojis, {
+      frequentlyUsedCatgegory = this.renderCategory('Frequently used', frequentlyUsedEmojis, {
         menuListClass: 'frequent-emojis',
       });
     }
@@ -179,7 +160,7 @@ export default class AwardsHandler {
     }
     this.isAddingRemainingEmojiMenuCategories = true;
 
-    const categoryMap = Emoji.getEmojiCategoryMap();
+    const categoryMap = this.emoji.getEmojiCategoryMap();
 
     // Avoid the jank and render the remaining categories separately
     // This will take more time, but makes UI more responsive
@@ -191,7 +172,7 @@ export default class AwardsHandler {
         promiseChain.then(() =>
           new Promise((resolve) => {
             const emojisInCategory = categoryMap[categoryNameKey];
-            const categoryMarkup = renderCategory(
+            const categoryMarkup = this.renderCategory(
               categoryLabelMap[categoryNameKey],
               emojisInCategory,
             );
@@ -216,6 +197,25 @@ export default class AwardsHandler {
     });
   }
 
+  renderCategory(name, emojiList, opts = {}) {
+    return `
+      <h5 class="emoji-menu-title">
+        ${name}
+      </h5>
+      <ul class="clearfix emoji-menu-list ${opts.menuListClass || ''}">
+        ${emojiList.map(emojiName => `
+          <li class="emoji-menu-list-item">
+            <button class="emoji-menu-btn text-center js-emoji-btn" type="button">
+              ${this.emoji.glEmojiTag(emojiName, {
+                sprite: true,
+              })}
+            </button>
+          </li>
+        `).join('\n')}
+      </ul>
+    `;
+  }
+
   positionMenu($menu, $addBtn) {
     const position = $addBtn.data('position');
     // The menu could potentially be off-screen or in a hidden overflow element
@@ -234,7 +234,7 @@ export default class AwardsHandler {
   }
 
   addAward(votesBlock, awardUrl, emoji, checkMutuality, callback) {
-    const normalizedEmoji = Emoji.normalizeEmojiName(emoji);
+    const normalizedEmoji = this.emoji.normalizeEmojiName(emoji);
     const $emojiButton = this.findEmojiIcon(votesBlock, normalizedEmoji).parent();
     this.postEmoji($emojiButton, awardUrl, normalizedEmoji, () => {
       this.addAwardToEmojiBar(votesBlock, normalizedEmoji, checkMutuality);
@@ -249,7 +249,7 @@ export default class AwardsHandler {
       this.checkMutuality(votesBlock, emoji);
     }
     this.addEmojiToFrequentlyUsedList(emoji);
-    const normalizedEmoji = Emoji.normalizeEmojiName(emoji);
+    const normalizedEmoji = this.emoji.normalizeEmojiName(emoji);
     const $emojiButton = this.findEmojiIcon(votesBlock, normalizedEmoji).parent();
     if ($emojiButton.length > 0) {
       if (this.isActive($emojiButton)) {
@@ -374,7 +374,7 @@ export default class AwardsHandler {
   createAwardButtonForVotesBlock(votesBlock, emojiName) {
     const buttonHtml = `
       <button class="btn award-control js-emoji-btn has-tooltip active" title="You" data-placement="bottom">
-        ${Emoji.glEmojiTag(emojiName)}
+        ${this.emoji.glEmojiTag(emojiName)}
         <span class="award-control-text js-counter">1</span>
       </button>
     `;
@@ -440,7 +440,7 @@ export default class AwardsHandler {
   }
 
   addEmojiToFrequentlyUsedList(emoji) {
-    if (Emoji.isEmojiNameValid(emoji)) {
+    if (this.emoji.isEmojiNameValid(emoji)) {
       this.frequentlyUsedEmojis = _.uniq(this.getFrequentlyUsedEmojis().concat(emoji));
       Cookies.set('frequently_used_emojis', this.frequentlyUsedEmojis.join(','), { expires: 365 });
     }
@@ -450,7 +450,7 @@ export default class AwardsHandler {
     return this.frequentlyUsedEmojis || (() => {
       const frequentlyUsedEmojis = _.uniq((Cookies.get('frequently_used_emojis') || '').split(','));
       this.frequentlyUsedEmojis = frequentlyUsedEmojis.filter(
-        inputName => Emoji.isEmojiNameValid(inputName),
+        inputName => this.emoji.isEmojiNameValid(inputName),
       );
 
       return this.frequentlyUsedEmojis;
@@ -493,7 +493,7 @@ export default class AwardsHandler {
   }
 
   findMatchingEmojiElements(query) {
-    const emojiMatches = Emoji.filterEmojiNamesByAlias(query);
+    const emojiMatches = this.emoji.filterEmojiNamesByAlias(query);
     const $emojiElements = $('.emoji-menu-list:not(.frequent-emojis) [data-name]');
     const $matchingElements = $emojiElements
       .filter((i, elm) => emojiMatches.indexOf(elm.dataset.name) >= 0);
@@ -507,3 +507,12 @@ export default class AwardsHandler {
     $('.emoji-menu').remove();
   }
 }
+
+let awardsHandlerPromise = null;
+export default function loadAwardsHandler(reload = false) {
+  if (!awardsHandlerPromise || reload) {
+    awardsHandlerPromise = import(/* webpackChunkName: 'emoji' */ './emoji')
+      .then(Emoji => new AwardsHandler(Emoji));
+  }
+  return awardsHandlerPromise;
+}
diff --git a/app/assets/javascripts/behaviors/gl_emoji.js b/app/assets/javascripts/behaviors/gl_emoji.js
index 8156e491a42..7e98e04303a 100644
--- a/app/assets/javascripts/behaviors/gl_emoji.js
+++ b/app/assets/javascripts/behaviors/gl_emoji.js
@@ -1,5 +1,4 @@
 import installCustomElements from 'document-register-element';
-import { emojiImageTag, emojiFallbackImageSrc } from '../emoji';
 import isEmojiUnicodeSupported from '../emoji/support';
 
 installCustomElements(window);
@@ -32,11 +31,19 @@ export default function installGlEmojiElement() {
         // IE 11 doesn't like adding multiple at once :(
         this.classList.add('emoji-icon');
         this.classList.add(fallbackSpriteClass);
-      } else if (hasImageFallback) {
-        this.innerHTML = emojiImageTag(name, fallbackSrc);
       } else {
-        const src = emojiFallbackImageSrc(name);
-        this.innerHTML = emojiImageTag(name, src);
+        import(/* webpackChunkName: 'emoji' */ '../emoji')
+          .then(({ emojiImageTag, emojiFallbackImageSrc }) => {
+            if (hasImageFallback) {
+              this.innerHTML = emojiImageTag(name, fallbackSrc);
+            } else {
+              const src = emojiFallbackImageSrc(name);
+              this.innerHTML = emojiImageTag(name, src);
+            }
+          })
+          .catch(() => {
+            // do nothing
+          });
       }
     }
   };
diff --git a/app/assets/javascripts/gfm_auto_complete.js b/app/assets/javascripts/gfm_auto_complete.js
index 10a64f9032b..2c56b718212 100644
--- a/app/assets/javascripts/gfm_auto_complete.js
+++ b/app/assets/javascripts/gfm_auto_complete.js
@@ -1,4 +1,3 @@
-import { validEmojiNames, glEmojiTag } from './emoji';
 import glRegexp from './lib/utils/regexp';
 import AjaxCache from './lib/utils/ajax_cache';
 
@@ -373,7 +372,12 @@ class GfmAutoComplete {
     if (this.cachedData[at]) {
       this.loadData($input, at, this.cachedData[at]);
     } else if (GfmAutoComplete.atTypeMap[at] === 'emojis') {
-      this.loadData($input, at, validEmojiNames);
+      import(/* webpackChunkName: 'emoji' */ './emoji')
+        .then(({ validEmojiNames, glEmojiTag }) => {
+          this.loadData($input, at, validEmojiNames);
+          GfmAutoComplete.glEmojiTag = glEmojiTag;
+        })
+        .catch(() => { this.isLoadingData[at] = false; });
     } else {
       AjaxCache.retrieve(this.dataSources[GfmAutoComplete.atTypeMap[at]], true)
         .then((data) => {
@@ -428,12 +432,14 @@ GfmAutoComplete.atTypeMap = {
 };
 
 // Emoji
+GfmAutoComplete.glEmojiTag = null;
 GfmAutoComplete.Emoji = {
   templateFunction(name) {
-    return `<li>
-      ${name} ${glEmojiTag(name)}
-    </li>
-    `;
+    // glEmojiTag helper is loaded on-demand in fetchData()
+    if (GfmAutoComplete.glEmojiTag) {
+      return `<li>${name} ${GfmAutoComplete.glEmojiTag(name)}</li>`;
+    }
+    return `<li>${name}</li>`;
   },
 };
 // Team Members
diff --git a/app/assets/javascripts/main.js b/app/assets/javascripts/main.js
index de1b658f602..fe752d95b90 100644
--- a/app/assets/javascripts/main.js
+++ b/app/assets/javascripts/main.js
@@ -70,7 +70,7 @@ import './ajax_loading_spinner';
 import './api';
 import './aside';
 import './autosave';
-import AwardsHandler from './awards_handler';
+import loadAwardsHandler from './awards_handler';
 import './breakpoints';
 import './broadcast_message';
 import './build';
@@ -355,7 +355,7 @@ $(function () {
   $window.off('resize.app').on('resize.app', function () {
     return fitSidebarForSize();
   });
-  gl.awardsHandler = new AwardsHandler();
+  loadAwardsHandler();
   new Aside();
 
   gl.utils.renderTimeago();
diff --git a/app/assets/javascripts/notes.js b/app/assets/javascripts/notes.js
index 194d1730f3d..555b8c8a65c 100644
--- a/app/assets/javascripts/notes.js
+++ b/app/assets/javascripts/notes.js
@@ -18,6 +18,7 @@ import 'vendor/jquery.caret'; // required by jquery.atwho
 import 'vendor/jquery.atwho';
 import AjaxCache from '~/lib/utils/ajax_cache';
 import CommentTypeToggle from './comment_type_toggle';
+import loadAwardsHandler from './awards_handler';
 import './autosave';
 import './dropzone_input';
 import './task_list';
@@ -291,8 +292,13 @@ export default class Notes {
 
       if ('emoji_award' in noteEntity.commands_changes) {
         votesBlock = $('.js-awards-block').eq(0);
-        gl.awardsHandler.addAwardToEmojiBar(votesBlock, noteEntity.commands_changes.emoji_award);
-        return gl.awardsHandler.scrollToAwards();
+
+        loadAwardsHandler().then((awardsHandler) => {
+          awardsHandler.addAwardToEmojiBar(votesBlock, noteEntity.commands_changes.emoji_award);
+          awardsHandler.scrollToAwards();
+        }).catch(() => {
+          // ignore
+        });
       }
     }
   }
diff --git a/app/assets/javascripts/webpack.js b/app/assets/javascripts/webpack.js
new file mode 100644
index 00000000000..9a9cf395fb8
--- /dev/null
+++ b/app/assets/javascripts/webpack.js
@@ -0,0 +1,9 @@
+/**
+ * This is the first script loaded by webpack's runtime. It is used to manually configure
+ * config.output.publicPath to account for relative_url_root or CDN settings which cannot be
+ * baked-in to our webpack bundles.
+ */
+
+if (gon && gon.webpack_public_path) {
+  __webpack_public_path__ = gon.webpack_public_path; // eslint-disable-line
+}
diff --git a/app/helpers/webpack_helper.rb b/app/helpers/webpack_helper.rb
index 6bacda9fe75..0386df22374 100644
--- a/app/helpers/webpack_helper.rb
+++ b/app/helpers/webpack_helper.rb
@@ -11,20 +11,29 @@ module WebpackHelper
 
     paths = Webpack::Rails::Manifest.asset_paths(source)
     if extension
-      paths = paths.select { |p| p.ends_with? ".#{extension}" }
+      paths.select! { |p| p.ends_with? ".#{extension}" }
     end
 
-    # include full webpack-dev-server url for rspec tests running locally
+    force_host = webpack_public_host
+    if force_host
+      paths.map! { |p| "#{force_host}#{p}" }
+    end
+
+    paths
+  end
+
+  def webpack_public_host
     if Rails.env.test? && Rails.configuration.webpack.dev_server.enabled
       host = Rails.configuration.webpack.dev_server.host
       port = Rails.configuration.webpack.dev_server.port
       protocol = Rails.configuration.webpack.dev_server.https ? 'https' : 'http'
-
-      paths.map! do |p|
-        "#{protocol}://#{host}:#{port}#{p}"
-      end
+      "#{protocol}://#{host}:#{port}"
+    else
+      ActionController::Base.asset_host.try(:chomp, '/')
     end
+  end
 
-    paths
+  def webpack_public_path
+    "#{webpack_public_host}/#{Rails.application.config.webpack.public_path}/"
   end
 end
diff --git a/app/views/layouts/_head.html.haml b/app/views/layouts/_head.html.haml
index cc710f4ec7d..abb6dc2e9f3 100644
--- a/app/views/layouts/_head.html.haml
+++ b/app/views/layouts/_head.html.haml
@@ -38,7 +38,7 @@
 
   = Gon::Base.render_data
 
-  = webpack_bundle_tag "runtime"
+  = webpack_bundle_tag "webpack_runtime"
   = webpack_bundle_tag "common"
   = webpack_bundle_tag "locale"
   = webpack_bundle_tag "main"
diff --git a/changelogs/unreleased/enable-webpack-code-splitting.yml b/changelogs/unreleased/enable-webpack-code-splitting.yml
new file mode 100644
index 00000000000..d61c3b97d11
--- /dev/null
+++ b/changelogs/unreleased/enable-webpack-code-splitting.yml
@@ -0,0 +1,5 @@
+---
+title: Enable support for webpack code-splitting by dynamically setting publicPath
+  at runtime
+merge_request: 12032
+author:
diff --git a/config/webpack.config.js b/config/webpack.config.js
index 90ef6a5448b..cbb0a899638 100644
--- a/config/webpack.config.js
+++ b/config/webpack.config.js
@@ -71,6 +71,7 @@ var config = {
     vue_merge_request_widget: './vue_merge_request_widget/index.js',
     test:                 './test.js',
     peek:                 './peek.js',
+    webpack_runtime:      './webpack.js',
   },
 
   output: {
@@ -190,7 +191,7 @@ var config = {
 
     // create cacheable common library bundles
     new webpack.optimize.CommonsChunkPlugin({
-      names: ['main', 'locale', 'common', 'runtime'],
+      names: ['main', 'locale', 'common', 'webpack_runtime'],
     }),
   ],
 
@@ -245,7 +246,6 @@ if (IS_DEV_SERVER) {
     hot: DEV_SERVER_LIVERELOAD,
     inline: DEV_SERVER_LIVERELOAD
   };
-  config.output.publicPath = '//' + DEV_SERVER_HOST + ':' + DEV_SERVER_PORT + config.output.publicPath;
   config.plugins.push(
     // watch node_modules for changes if we encounter a missing module compile error
     new WatchMissingNodeModulesPlugin(path.join(ROOT_PATH, 'node_modules'))
diff --git a/lib/gitlab/gon_helper.rb b/lib/gitlab/gon_helper.rb
index 319633656ff..2d1ae6a5925 100644
--- a/lib/gitlab/gon_helper.rb
+++ b/lib/gitlab/gon_helper.rb
@@ -2,11 +2,14 @@
 
 module Gitlab
   module GonHelper
+    include WebpackHelper
+
     def add_gon_variables
       gon.api_version            = 'v4'
       gon.default_avatar_url     = URI.join(Gitlab.config.gitlab.url, ActionController::Base.helpers.image_path('no_avatar.png')).to_s
       gon.max_file_size          = current_application_settings.max_attachment_size
       gon.asset_host             = ActionController::Base.asset_host
+      gon.webpack_public_path    = webpack_public_path
       gon.relative_url_root      = Gitlab.config.gitlab.relative_url_root
       gon.shortcuts_path         = help_page_path('shortcuts')
       gon.user_color_scheme      = Gitlab::ColorSchemes.for_user(current_user).css_class
diff --git a/package.json b/package.json
index 045f07ee2f9..5a997e813f8 100644
--- a/package.json
+++ b/package.json
@@ -13,6 +13,7 @@
   },
   "dependencies": {
     "babel-core": "^6.22.1",
+    "babel-eslint": "^7.2.1",
     "babel-loader": "^6.2.10",
     "babel-plugin-transform-define": "^1.2.0",
     "babel-preset-latest": "^6.24.0",
diff --git a/spec/javascripts/awards_handler_spec.js b/spec/javascripts/awards_handler_spec.js
index 3fc03324d16..8e056882108 100644
--- a/spec/javascripts/awards_handler_spec.js
+++ b/spec/javascripts/awards_handler_spec.js
@@ -1,7 +1,7 @@
 /* eslint-disable space-before-function-paren, no-var, one-var, one-var-declaration-per-line, no-unused-expressions, comma-dangle, new-parens, no-unused-vars, quotes, jasmine/no-spec-dupes, prefer-template, max-len */
 
 import Cookies from 'js-cookie';
-import AwardsHandler from '~/awards_handler';
+import loadAwardsHandler from '~/awards_handler';
 
 import '~/lib/utils/common_utils';
 
@@ -26,14 +26,13 @@ import '~/lib/utils/common_utils';
 
   describe('AwardsHandler', function() {
     preloadFixtures('issues/issue_with_comment.html.raw');
-    beforeEach(function() {
+    beforeEach(function(done) {
       loadFixtures('issues/issue_with_comment.html.raw');
-      awardsHandler = new AwardsHandler;
-      spyOn(awardsHandler, 'postEmoji').and.callFake((function(_this) {
-        return function(button, url, emoji, cb) {
-          return cb();
-        };
-      })(this));
+      loadAwardsHandler(true).then((obj) => {
+        awardsHandler = obj;
+        spyOn(awardsHandler, 'postEmoji').and.callFake((button, url, emoji, cb) => cb());
+        done();
+      }).catch(fail);
 
       let isEmojiMenuBuilt = false;
       openAndWaitForEmojiMenu = function() {
diff --git a/yarn.lock b/yarn.lock
index b902d5235d0..b04eebe60af 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -265,6 +265,15 @@ babel-core@^6.22.1, babel-core@^6.23.0:
     slash "^1.0.0"
     source-map "^0.5.0"
 
+babel-eslint@^7.2.1:
+  version "7.2.1"
+  resolved "https://registry.yarnpkg.com/babel-eslint/-/babel-eslint-7.2.1.tgz#079422eb73ba811e3ca0865ce87af29327f8c52f"
+  dependencies:
+    babel-code-frame "^6.22.0"
+    babel-traverse "^6.23.1"
+    babel-types "^6.23.0"
+    babylon "^6.16.1"
+
 babel-generator@^6.18.0, babel-generator@^6.23.0:
   version "6.23.0"
   resolved "https://registry.yarnpkg.com/babel-generator/-/babel-generator-6.23.0.tgz#6b8edab956ef3116f79d8c84c5a3c05f32a74bc5"
@@ -816,10 +825,14 @@ babel-types@^6.18.0, babel-types@^6.19.0, babel-types@^6.22.0, babel-types@^6.23
     lodash "^4.2.0"
     to-fast-properties "^1.0.1"
 
-babylon@^6.11.0, babylon@^6.13.0, babylon@^6.15.0:
+babylon@^6.11.0:
   version "6.15.0"
   resolved "https://registry.yarnpkg.com/babylon/-/babylon-6.15.0.tgz#ba65cfa1a80e1759b0e89fb562e27dccae70348e"
 
+babylon@^6.13.0, babylon@^6.15.0, babylon@^6.16.1:
+  version "6.16.1"
+  resolved "https://registry.yarnpkg.com/babylon/-/babylon-6.16.1.tgz#30c5a22f481978a9e7f8cdfdf496b11d94b404d3"
+
 backo2@1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/backo2/-/backo2-1.0.2.tgz#31ab1ac8b129363463e35b3ebb69f4dfcfba7947"