Prebid core & PBS adapter: Feature tags and optional compilation of native support

.eslintrc.js

@@ -21,7 +21,8 @@ module.exports = {
   globals: {
     '$$PREBID_GLOBAL$$': false,
     'BROWSERSTACK_USERNAME': false,
-    'BROWSERSTACK_KEY': false
+    'BROWSERSTACK_KEY': false,
+    'FEATURES': 'readonly',
   },
   // use babel as parser for fancy syntax
   parser: '@babel/eslint-parser',

babelConfig.js

@@ -9,7 +9,8 @@ function useLocal(module) {
   })
 }
 
-module.exports = function (test = false) {
+module.exports = function (options = {}) {
+  const {globalVarName, disableFeatures} = options;
   return {
     'presets': [
       [
@@ -18,12 +19,15 @@ module.exports = function (test = false) {
           'useBuiltIns': 'entry',
           'corejs': '3.13.0',
           // a lot of tests use sinon.stub & others that stopped working on ES6 modules with webpack 5
-          'modules': test ? 'commonjs' : 'auto',
+          'modules': options.test ? 'commonjs' : 'auto',
         }
       ]
     ],
     'plugins': [
-      path.resolve(__dirname, './plugins/pbjsGlobals.js'),
+      [
+        path.resolve(__dirname, './plugins/pbjsGlobals.js'),
+        {globalVarName, disableFeatures}
+      ],
       useLocal('babel-plugin-transform-object-assign'),
     ],
   }

features.json

@@ -0,0 +1,3 @@
+[
+  "NATIVE"
+]

gulpHelpers.js

@@ -169,5 +169,11 @@ module.exports = {
     }
 
     return options;
-  }
+  },
+  getDisabledFeatures() {
+    return (argv.disable || '')
+      .split(',')
+      .map((s) => s.trim())
+      .filter((s) => s);
+  },
 };

gulpfile.js

@@ -35,6 +35,7 @@ var port = 9999;
 const FAKE_SERVER_HOST = argv.host ? argv.host : 'localhost';
 const FAKE_SERVER_PORT = 4444;
 const { spawn } = require('child_process');
+const TerserPlugin = require('terser-webpack-plugin');
 
 // these modules must be explicitly listed in --modules to be included in the build, won't be part of "all" modules
 var explicitModules = [
@@ -132,20 +133,22 @@ function makeDevpackPkg() {
     .pipe(connect.reload());
 }
 
-function makeWebpackPkg() {
-  var cloned = _.cloneDeep(webpackConfig);
+function makeWebpackPkg(extraConfig = {}) {
+  var cloned = _.merge(_.cloneDeep(webpackConfig), (extraConfig || {}));
   delete cloned.devtool;
 
-  var externalModules = helpers.getArgModules();
+  return function buildBundle() {
+    var externalModules = helpers.getArgModules();
 
-  const analyticsSources = helpers.getAnalyticsSources();
-  const moduleSources = helpers.getModulePaths(externalModules);
+    const analyticsSources = helpers.getAnalyticsSources();
+    const moduleSources = helpers.getModulePaths(externalModules);
 
-  return gulp.src([].concat(moduleSources, analyticsSources, 'src/prebid.js'))
-    .pipe(helpers.nameModules(externalModules))
-    .pipe(webpackStream(cloned, webpack))
-    .pipe(gulpif(file => file.basename === 'prebid-core.js', header(banner, { prebid: prebid })))
-    .pipe(gulp.dest('build/dist'));
+    return gulp.src([].concat(moduleSources, analyticsSources, 'src/prebid.js'))
+      .pipe(helpers.nameModules(externalModules))
+      .pipe(webpackStream(cloned, webpack))
+      .pipe(gulpif(file => file.basename === 'prebid-core.js', header(banner, {prebid: prebid})))
+      .pipe(gulp.dest('build/dist'));
+  }
 }
 
 function getModulesListToAddInBanner(modules) {
@@ -224,9 +227,11 @@ function bundle(dev, moduleArr) {
 
 function testTaskMaker(options = {}) {
   ['watch', 'e2e', 'file', 'browserstack', 'notest'].forEach(opt => {
-    options[opt] = options[opt] || argv[opt];
+    options[opt] = options.hasOwnProperty(opt) ? options[opt] : argv[opt];
   })
 
+  options.disableFeatures = options.disableFeatures || helpers.getDisabledFeatures();
+
   return function test(done) {
     if (options.notest) {
       done();
@@ -270,13 +275,15 @@ function testTaskMaker(options = {}) {
           process.exit(1);
         });
     } else {
-      var karmaConf = karmaConfMaker(false, options.browserstack, options.watch, options.file);
+      var karmaConf = karmaConfMaker(false, options.browserstack, options.watch, options.file, options.disableFeatures);
 
       var browserOverride = helpers.parseBrowserArgs(argv);
       if (browserOverride.length > 0) {
         karmaConf.browsers = browserOverride;
       }
-
+      if (options.oneBrowser) {
+        karmaConf.browsers = [karmaConf.browsers.find((b) => b.toLowerCase().includes(options.oneBrowser.toLowerCase())) || karmaConf.browsers[0]]
+      }
       new KarmaServer(karmaConf, newKarmaCallback(done)).start();
     }
   }
@@ -293,9 +300,6 @@ function newKarmaCallback(done) {
       }
     } else {
       done();
-      if (argv.browserstack) {
-        process.exit(exitCode);
-      }
     }
   }
 }
@@ -398,11 +402,30 @@ gulp.task(clean);
 gulp.task(escapePostbidConfig);
 
 gulp.task('build-bundle-dev', gulp.series(makeDevpackPkg, gulpBundle.bind(null, true)));
-gulp.task('build-bundle-prod', gulp.series(makeWebpackPkg, gulpBundle.bind(null, false)));
+gulp.task('build-bundle-prod', gulp.series(makeWebpackPkg(), gulpBundle.bind(null, false)));
+// build-bundle-verbose - prod bundle except names and comments are preserved. Use this to see the effects
+// of dead code elimination.
+gulp.task('build-bundle-verbose', gulp.series(makeWebpackPkg({
+  optimization: {
+    minimizer: [
+      new TerserPlugin({
+        parallel: true,
+        terserOptions: {
+          mangle: false,
+          format: {
+            comments: 'all'
+          }
+        },
+        extractComments: false,
+      }),
+    ],
+  }
+}), gulpBundle.bind(null, false)));
 
 // public tasks (dependencies are needed for each task since they can be ran on their own)
 gulp.task('test-only', test);
-gulp.task('test', gulp.series(clean, lint, 'test-only'));
+gulp.task('test-all-features-disabled', testTaskMaker({disableFeatures: require('./features.json'), oneBrowser: 'chrome', watch: false}))
+gulp.task('test', gulp.series(clean, lint, 'test-all-features-disabled', 'test-only'));
 
 gulp.task('test-coverage', gulp.series(clean, testCoverage));
 gulp.task(viewCoverage);
@@ -417,7 +440,7 @@ gulp.task('serve-fast', gulp.series(clean, gulp.parallel('build-bundle-dev', wat
 gulp.task('serve-and-test', gulp.series(clean, gulp.parallel('build-bundle-dev', watchFast, testTaskMaker({watch: true}))));
 gulp.task('serve-fake', gulp.series(clean, gulp.parallel('build-bundle-dev', watch), injectFakeServerEndpointDev, test, startFakeServer));
 
-gulp.task('default', gulp.series(clean, makeWebpackPkg));
+gulp.task('default', gulp.series(clean, makeWebpackPkg()));
 
 gulp.task('e2e-test', gulp.series(clean, setupE2e, gulp.parallel('build-bundle-prod', watch), injectFakeServerEndpoint, test));
 // other tasks

karma.conf.maker.js

@@ -7,7 +7,7 @@ var _ = require('lodash');
 var webpackConf = require('./webpack.conf.js');
 var karmaConstants = require('karma').constants;
 
-function newWebpackConfig(codeCoverage) {
+function newWebpackConfig(codeCoverage, disableFeatures) {
   // Make a clone here because we plan on mutating this object, and don't want parallel tasks to trample each other.
   var webpackConfig = _.cloneDeep(webpackConf);
 
@@ -22,7 +22,7 @@ function newWebpackConfig(codeCoverage) {
     .flatMap((r) => r.use)
     .filter((use) => use.loader === 'babel-loader')
     .forEach((use) => {
-      use.options = babelConfig(true);
+      use.options = babelConfig({test: true, disableFeatures: disableFeatures});
     });
 
   if (codeCoverage) {
@@ -117,8 +117,8 @@ function setBrowsers(karmaConf, browserstack) {
   }
 }
 
-module.exports = function(codeCoverage, browserstack, watchMode, file) {
-  var webpackConfig = newWebpackConfig(codeCoverage);
+module.exports = function(codeCoverage, browserstack, watchMode, file, disableFeatures) {
+  var webpackConfig = newWebpackConfig(codeCoverage, disableFeatures);
   var plugins = newPluginsArray(browserstack);
 
   var files = file ? ['test/test_deps.js', file] : ['test/test_index.js'];