Issue 5535 - Replace our module system with webpack

webpack.config.js

Index: webpack.config.js
diff --git a/webpack.config.js b/webpack.config.js
new file mode 100644
index 0000000000000000000000000000000000000000..12d023ceaaf8d9eb57ac36ca799dd4e9829a8fbb
--- /dev/null
+++ b/webpack.config.js
@@ -0,0 +1,96 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-present eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+const path = require("path");
+
+let {EXTENSION_PATH, ENTRY_POINTS, OUTPUT_PATH, BUNDLE_NAME,
+     RESOLVE_PATHS, INFO_PATH} = require("process").env;
+
+module.exports = {
+  context: EXTENSION_PATH,
+  devtool: "source-map",
+  entry: ENTRY_POINTS.split(" "),
+  externals: {
+    // Workaround for the fact that adblockplusui attempts to require
+    // "ext_background" (meaning adblockplusui/ext/background.js) if ext is
+    // falsey at bundle time. Once we've gotten rid of ext, or at least
+    // removed those requires from adblockplusui we can remove this.
+    ext_background: "ext"

[Sebastian Noack, 2017/09/24 15:03:38]

adblockplusui attempts to require ext_background only for the legacy Gecko
extension. This require should be removed now. There is no need to turn ext into
a module for the WebExtension, we should rather get rid of it eventually.

[kzar, 2017/09/24 16:02:46]

FWIW This workaround simply avoids webpack replacing require("ext_background")
with anything, which is required since `ext` is falsey at bundle time but not at
runtime for the extension[1]. It doesn't turn ext into a module. 

But of course I agree, if we can remove the require and this workaround then
even better.

[1] For reference in case someone else's reading through this discussion the
line in adblockplusui/messageResponder.js looks like `let ext = global.ext ||
require("ext_background");`.

[Sebastian Noack, 2017/09/24 20:42:15]

You already removed other code from adblockplusui that was necessary for the
legacy Gecko extension to work, but had to be removed for Webpack:
https://hg.adblockplus.org/adblockplusui/rev/2fb191f6a20c

This is the same with require("ext_background"), no reason to go with a
workaround, this time, IMO.

[kzar, 2017/09/25 15:18:27]

Done. (awaiting https://codereview.adblockplus.org/29555744/)

+  },
+  output: {
+    path: OUTPUT_PATH,
+    filename: BUNDLE_NAME
+  },
+  resolve: {
+    modules: RESOLVE_PATHS.split(" "),
+    alias: {
+      info$: INFO_PATH,
+      // Prevent builtin Node.js modules from being used instead of our own when
+      // the names clash. Once relative paths are used this won't be necessary.
+      url$: "url.js",
+      events$: "events.js",
+      punycode$: "punycode.js"
+    },
+    plugins: [
+      function()
+      {
+        // Our old module system in packagerChrome.py used to prefix
+        // module names with the name of their parent directory and an
+        // underscore - but only when that directory wasn't called
+        // "lib". This plugin is for backwards compatability, but can
+        // be removed once use of that deprecated syntax has been
+        // replaced.
+        this.plugin("described-resolve", (request, callback) =>
+        {
+          let target = request.request;
+
+          let prefix_index = target.indexOf("_");
+          if (prefix_index == -1)
+            return callback();
+
+          let prefix = target.substring(0, prefix_index);
+          if (prefix == "lib")
+            return callback();
+
+          let fixed_target = path.join(prefix,
+                                       target.substring(prefix_index + 1));
+          return this.doResolve(
+            "resolve", Object.assign({}, request, {request: fixed_target}),
+            "Changed prefixed path using legacy buildtools syntax from " +
+            target + " to " + fixed_target,
+            callback
+          );
+        });
+      }
+    ]
+  },
+  stats: {
+    assets: false,
+    children: false,
+    chunks: false,
+    errorDetails: true,
+    errors: true,
+    hash: false,
+    modules: false,
+    publicPath: false,
+    reasons: false,
+    source: false,
+    timings: false,
+    version: false,
+    warnings: true
+  }
+};