From d3a103300853880ff1d2df96862e9a68b59b13eb Mon Sep 17 00:00:00 2001
From: Thomas Randolph <trandolph@gitlab.com>
Date: Mon, 4 Jan 2021 12:35:33 -0700
Subject: [PATCH 1/2] Switch to faster PRNG

---
 app/assets/javascripts/diffs/utils/uuids.js |  4 ++--
 jest.config.base.js                         |  2 +-
 package.json                                |  2 +-
 yarn.lock                                   | 10 +++++-----
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/app/assets/javascripts/diffs/utils/uuids.js b/app/assets/javascripts/diffs/utils/uuids.js
index 12448350e62e8b..1fe5f9f6499a43 100644
--- a/app/assets/javascripts/diffs/utils/uuids.js
+++ b/app/assets/javascripts/diffs/utils/uuids.js
@@ -11,7 +11,7 @@
  * @typedef {String} UUIDv4
  */
 
-import MersenneTwister from 'mersenne-twister';
+import { MersenneTwister } from 'fast-mersenne-twister';
 import stringHash from 'string-hash';
 import { isString } from 'lodash';
 import { v4 } from 'uuid';
@@ -49,7 +49,7 @@ function randomValuesForUuid(prng) {
     const buffer = new ArrayBuffer(4);
     const view = new DataView(buffer);
 
-    view.setUint32(0, prng.random_int());
+    view.setUint32(0, prng.randomNumber());
 
     randomValues.push(view.getUint8(0), view.getUint8(1), view.getUint8(2), view.getUint8(3));
   }
diff --git a/jest.config.base.js b/jest.config.base.js
index ffd365b9eaa34b..3ac6aa9091c82c 100644
--- a/jest.config.base.js
+++ b/jest.config.base.js
@@ -91,7 +91,7 @@ module.exports = (path) => {
       '^.+\\.(md|zip|png)$': 'jest-raw-loader',
     },
     transformIgnorePatterns: [
-      'node_modules/(?!(@gitlab/ui|bootstrap-vue|three|monaco-editor|monaco-yaml)/)',
+      'node_modules/(?!(@gitlab/ui|bootstrap-vue|three|monaco-editor|monaco-yaml|fast-mersenne-twister)/)',
     ],
     timers: 'fake',
     testEnvironment: '<rootDir>/spec/frontend/environment.js',
diff --git a/package.json b/package.json
index b33944562f7af3..9dcdd5690961bb 100644
--- a/package.json
+++ b/package.json
@@ -87,6 +87,7 @@
     "emoji-regex": "^7.0.3",
     "emoji-unicode-version": "^0.2.1",
     "exports-loader": "^0.7.0",
+    "fast-mersenne-twister": "1.0.2",
     "file-loader": "^5.1.0",
     "font-awesome": "4.7.0",
     "fuzzaldrin-plus": "^0.6.0",
@@ -110,7 +111,6 @@
     "marked": "^0.3.12",
     "mathjax": "3",
     "mermaid": "^8.5.2",
-    "mersenne-twister": "1.1.0",
     "minimatch": "^3.0.4",
     "miragejs": "^0.1.40",
     "mock-apollo-client": "^0.5.0",
diff --git a/yarn.lock b/yarn.lock
index 6eb8bc1ec735f1..eac1d3462269ef 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5009,6 +5009,11 @@ fast-levenshtein@~2.0.6:
   resolved "https://registry.yarnpkg.com/fast-levenshtein/-/fast-levenshtein-2.0.6.tgz#3d8a5c66883a16a30ca8643e851f19baa7797917"
   integrity sha1-PYpcZog6FqMMqGQ+hR8Zuqd5eRc=
 
+fast-mersenne-twister@1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/fast-mersenne-twister/-/fast-mersenne-twister-1.0.2.tgz#5ead7caf3ace592a5789d11767732bd81cbaaa56"
+  integrity sha512-IaClPxsoBu3MxGpcURyjV8otT5Bj4ARoK0KBCJGnEVnD1A/qclL5eIeYiUuwG/WWJPxL1jlK61HTm2T6SBmvBQ==
+
 fault@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/fault/-/fault-1.0.2.tgz#c3d0fec202f172a3a4d414042ad2bb5e2a3ffbaa"
@@ -8190,11 +8195,6 @@ mermaid@^8.5.2:
     moment-mini "^2.22.1"
     scope-css "^1.2.1"
 
-mersenne-twister@1.1.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/mersenne-twister/-/mersenne-twister-1.1.0.tgz#f916618ee43d7179efcf641bec4531eb9670978a"
-  integrity sha1-+RZhjuQ9cXnvz2Qb7EUx65Zwl4o=
-
 methods@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/methods/-/methods-1.1.2.tgz#5529a4d67654134edcc5266656835b0f851afcee"
-- 
GitLab


From 2a28ff9dd801af3b66442303246208cf55a85ea5 Mon Sep 17 00:00:00 2001
From: Thomas Randolph <trandolph@gitlab.com>
Date: Tue, 5 Jan 2021 02:32:53 -0700
Subject: [PATCH 2/2] Add changelog for swapping the Mersenne Twister in Diffs

---
 changelogs/unreleased/maintenance-fast-mersenne-twister.yml | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 changelogs/unreleased/maintenance-fast-mersenne-twister.yml

diff --git a/changelogs/unreleased/maintenance-fast-mersenne-twister.yml b/changelogs/unreleased/maintenance-fast-mersenne-twister.yml
new file mode 100644
index 00000000000000..1fb389e333b10b
--- /dev/null
+++ b/changelogs/unreleased/maintenance-fast-mersenne-twister.yml
@@ -0,0 +1,5 @@
+---
+title: Switch to 2x faster PRNG
+merge_request: 50811
+author:
+type: performance
-- 
GitLab