[WIP] Study possibility of moving from js-yaml to yaml

packages/yarnpkg-parsers/package.json

@@ -4,11 +4,11 @@
   "license": "BSD-2-Clause",
   "main": "./sources/index.ts",
   "dependencies": {
-    "js-yaml": "^3.10.0",
-    "tslib": "^1.13.0"
+    "tslib": "^1.13.0",
+    "yaml": "^2.0.0-10"
   },
   "devDependencies": {
-    "@types/js-yaml": "^3.11.1",
+    "js-yaml": "^3.10.0",
     "pegjs": "^0.10.0"
   },
   "scripts": {

packages/yarnpkg-parsers/sources/syml.ts

@@ -1,5 +1,4 @@
-import {safeLoad, FAILSAFE_SCHEMA} from 'js-yaml';
-
+import {parse as parseYaml}        from 'yaml';
 import {parse}                     from './grammars/syml';
 
 const simpleStringPattern = /^(?![-?:,\][{}#&*!|>'"%@` \t\r\n]).([ \t]*(?![,\][{}:# \t\r\n]).)*$/;
@@ -141,10 +140,22 @@ function parseViaJsYaml(source: string) {
   if (LEGACY_REGEXP.test(source))
     return parseViaPeg(source);
 
-  const value = safeLoad(source, {
-    schema: FAILSAFE_SCHEMA,
-    json: true,
-  });
+  // js-yaml@3 doesn't parse `key: true` as a boolean, but as a string.
+  // as far as I tested it makes the lock file invalid after install.
+  const reviver = (key: unknown, value: unknown) => {
+    if (value === true) {
+      return 'true';
+    } else if (value === false) {
+      return 'false';
+    }
+    return value;
+  }
+
+  const value = parseYaml(source, reviver, {
+    uniqueKeys: false,
+    schema: 'failsafe',
+    customTags: []
+  })
 
   // Empty files are parsed as `undefined` instead of an empty object
   // Empty files with 2 newlines or more are `null` instead

packages/yarnpkg-parsers/tests/syml.test.js

@@ -1,4 +1,8 @@
-import {parseSyml} from '@yarnpkg/parsers';
+import {parseSyml}                                     from '@yarnpkg/parsers';
+import fs                                              from 'fs';
+import { performance }                                 from 'perf_hooks';
+import {safeLoad as parseWithJsYaml, FAILSAFE_SCHEMA}  from 'js-yaml';
+import {parse as parseWithYaml }                       from 'yaml';
 
 describe(`Syml parser`, () => {
   it(`shouldn't confuse old-style values with new-style keys`, () => {
@@ -21,13 +25,48 @@ describe(`Syml parser`, () => {
 
   it(`should merge duplicates`, () => {
     expect(
-      parseSyml(`    
+      parseSyml(`
       "lodash@npm:^4.17.20":
         version: 4.17.20
-      
+
       "lodash@npm:^4.17.20":
         version: 4.17.20
       `),
     ).toEqual({'lodash@npm:^4.17.20': {version: `4.17.20`}});
   });
 });
+
+describe('Yaml parse comparison (to be removed / reworked)', () => {
+  it(`should parse identically as js-yaml@3`, () => {
+
+    const lock = fs.readFileSync(`${__dirname}/../../../yarn.lock`, `utf8`);
+
+    // js-yaml@3 doesn't parse `key: true` as a boolean, but as a string.
+    // as far as I tested it makes the lock file invalid after install.
+    const reviver = (key, value) => {
+      if (value === true) {
+        return 'true';
+      } else if (value === false) {
+        return 'false';
+      }
+      return value;
+    }
+
+    const startJsYaml = performance.now();
+    const jsYamlParsed = parseWithJsYaml(lock, {schema: FAILSAFE_SCHEMA});
+    const endJsYaml = performance.now();
+    const jsYamlTime = endJsYaml - startJsYaml;
+
+    const startYaml = performance.now();
+    const yamlParsed = parseWithYaml(lock, reviver, {
+      uniqueKeys: false,
+      schema: 'failsafe',
+      customTags: []
+    })
+    const endYaml = performance.now();
+    const yamlTime = endYaml - startYaml;
+
+    expect(yamlParsed).toStrictEqual(jsYamlParsed);
+    expect(yamlTime).toBeLessThan(jsYamlTime);
+  })
+})

yarn.lock

@@ -4287,13 +4287,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/js-yaml@npm:^3.11.1":
-  version: 3.12.5
-  resolution: "@types/js-yaml@npm:3.12.5"
-  checksum: fdc09cda3cc83a0c67d69ce179af9ede6e865f2e54f15b138814c5255b3b279306de2232da7cdea138248d885c960359ebf7f0bd21010e0ecf027f64454ab217
-  languageName: node
-  linkType: hard
-
 "@types/json-patch@npm:0.0.30":
   version: 0.0.30
   resolution: "@types/json-patch@npm:0.0.30"
@@ -5773,10 +5766,10 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@yarnpkg/parsers@workspace:packages/yarnpkg-parsers"
   dependencies:
-    "@types/js-yaml": ^3.11.1
     js-yaml: ^3.10.0
     pegjs: ^0.10.0
     tslib: ^1.13.0
+    yaml: ^2.0.0-10
   languageName: unknown
   linkType: soft
 
@@ -27468,6 +27461,13 @@ typescript@^3.8.3:
   languageName: node
   linkType: hard
 
+"yaml@npm:^2.0.0-10":
+  version: 2.0.0-10
+  resolution: "yaml@npm:2.0.0-10"
+  checksum: 7a0bac2f80225da6008fb8ab887f43166fb2485cc3e1350185c43499c76841ea0ca9d79b40c0970e08ab3943f25ffb184e709fef7fb8b26d73987ed0452a91cc
+  languageName: node
+  linkType: hard
+
 "yargs-parser@npm:^18.1.2":
   version: 18.1.3
   resolution: "yargs-parser@npm:18.1.3"