From 473c59b7ad26289ed308090a904ddad665287654 Mon Sep 17 00:00:00 2001
From: Mark Erikson <mark@isquaredsoftware.com>
Date: Mon, 20 Mar 2023 11:38:53 -0400
Subject: [PATCH] Remove now-obsolete import cleanup plugin

This was added as part of the "Interaction Tracking" work in #13509
back in 2018. That feature was removed in #20037 in 2020, and this
plugin appears to no longer have any effect on the build output.
---
 scripts/rollup/build.js                       |  4 ---
 .../rollup/plugins/strip-unused-imports.js    | 29 -------------------
 2 files changed, 33 deletions(-)
 delete mode 100644 scripts/rollup/plugins/strip-unused-imports.js

diff --git a/scripts/rollup/build.js b/scripts/rollup/build.js
index 46f5ae1a8954c..a0b39dd37f24b 100644
--- a/scripts/rollup/build.js
+++ b/scripts/rollup/build.js
@@ -18,7 +18,6 @@ const Stats = require('./stats');
 const Sync = require('./sync');
 const sizes = require('./plugins/sizes-plugin');
 const useForks = require('./plugins/use-forks-plugin');
-const stripUnusedImports = require('./plugins/strip-unused-imports');
 const dynamicImports = require('./plugins/dynamic-imports');
 const Packaging = require('./packaging');
 const {asyncRimRaf} = require('./utils');
@@ -430,9 +429,6 @@ function getPlugins(
         assume_function_wrapper: !isUMDBundle,
         renaming: !shouldStayReadable,
       }),
-    // HACK to work around the fact that Rollup isn't removing unused, pure-module imports.
-    // Note that this plugin must be called after closure applies DCE.
-    isProduction && stripUnusedImports(pureExternalModules),
     // Add the whitespace back if necessary.
     shouldStayReadable &&
       prettier({
diff --git a/scripts/rollup/plugins/strip-unused-imports.js b/scripts/rollup/plugins/strip-unused-imports.js
deleted file mode 100644
index a8b74142d811f..0000000000000
--- a/scripts/rollup/plugins/strip-unused-imports.js
+++ /dev/null
@@ -1,29 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-'use strict';
-
-module.exports = function stripUnusedImports(pureExternalModules) {
-  return {
-    name: 'scripts/rollup/plugins/strip-unused-imports',
-    renderChunk(code) {
-      pureExternalModules.forEach(module => {
-        // Ideally this would use a negative lookbehind: (?<!= *)
-        // But this isn't supported by the Node <= 8.9.
-        // So instead we try to handle the most common cases:
-        // 1. foo,bar=require("bar"),baz
-        // 2. foo;bar = require('bar');baz
-        // 3.   require('bar');
-        const regExp = new RegExp(
-          `([,;]| {2})require\\(["']${module}["']\\)[,;]`,
-          'g'
-        );
-        code = code.replace(regExp, '$1');
-      });
-      return {code};
-    },
-  };
-};