Infer EOLs from existing file or use OS EOL (#1911)

* When writing lockfile, yarnrc or manifest file, keep line endings as in existing file
* Implemented as proposed by @ahelmberger
* Resolves #1061

__tests__/commands/add.js

@@ -12,6 +12,8 @@ import Config from '../../src/config.js';
 import * as fs from '../../src/util/fs.js';
 import assert from 'assert';
 import semver from 'semver';
+import {promisify} from '../../src/util/promise';
+import fsNode from 'fs';
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 90000;
 
@@ -576,3 +578,29 @@ test.concurrent('add should generate correct integrity file', (): Promise<void>
     expect(allCorrect).toBe(true);
   });
 });
+
+test.concurrent('add infers line endings from existing win32 manifest file', async (): Promise<void> => {
+  await runAdd({}, ['is-online'], 'add-infers-line-endings-from-existing-manifest-file',
+    async (config): Promise<void> => {
+      const lockfile = await promisify(fsNode.readFile)(path.join(config.cwd, 'package.json'), 'utf8');
+      assert(/\r\n/.test(lockfile));
+      assert(!/[^\r]\n/.test(lockfile));
+    },
+    async (cwd): Promise<void> => {
+      const existingLockfile = '{ "dependencies": {} }\r\n';
+      await promisify(fsNode.writeFile)(path.join(cwd, 'package.json'), existingLockfile, 'utf8');
+    });
+});
+
+test.concurrent('add infers line endings from existing unix manifest file', async (): Promise<void> => {
+  await runAdd({}, ['is-online'], 'add-infers-line-endings-from-existing-manifest-file',
+    async (config): Promise<void> => {
+      const lockfile = await promisify(fsNode.readFile)(path.join(config.cwd, 'package.json'), 'utf8');
+      assert(/[^\r]\n/.test(lockfile));
+      assert(!/\r\n/.test(lockfile));
+    },
+    async (cwd): Promise<void> => {
+      const existingLockfile = '{ "dependencies": {} }\n';
+      await promisify(fsNode.writeFile)(path.join(cwd, 'package.json'), existingLockfile, 'utf8');
+    });
+});

__tests__/commands/install.js

@@ -10,6 +10,9 @@ import * as fs from '../../src/util/fs.js';
 import assert from 'assert';
 import semver from 'semver';
 import {getPackageVersion, explodeLockfile, runInstall, createLockfile} from './_install.js';
+import {promisify} from '../../src/util/promise';
+import fsNode from 'fs';
+import os from 'os';
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 90000;
 
@@ -692,3 +695,37 @@ test.concurrent('lockfile should be created when missing even if integrity match
     expect(await fs.exists(path.join(config.cwd, 'yarn.lock')));
   });
 });
+
+test.concurrent('install infers line endings from existing win32 lockfile', async (): Promise<void> => {
+  await runInstall({}, 'install-infers-line-endings-from-existing-lockfile',
+    async (config): Promise<void> => {
+      const lockfile = await promisify(fsNode.readFile)(path.join(config.cwd, 'yarn.lock'), 'utf8');
+      assert(/\r\n/.test(lockfile));
+      assert(!/[^\r]\n/.test(lockfile));
+    },
+    async (cwd): Promise<void> => {
+      const existingLockfile = '# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.\r\n';
+      await promisify(fsNode.writeFile)(path.join(cwd, 'yarn.lock'), existingLockfile, 'utf8');
+    });
+});
+
+test.concurrent('install infers line endings from existing unix lockfile', async (): Promise<void> => {
+  await runInstall({}, 'install-infers-line-endings-from-existing-lockfile',
+    async (config): Promise<void> => {
+      const lockfile = await promisify(fsNode.readFile)(path.join(config.cwd, 'yarn.lock'), 'utf8');
+      assert(/[^\r]\n/.test(lockfile));
+      assert(!/\r\n/.test(lockfile));
+    },
+    async (cwd): Promise<void> => {
+      const existingLockfile = '# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.\n';
+      await promisify(fsNode.writeFile)(path.join(cwd, 'yarn.lock'), existingLockfile, 'utf8');
+    });
+});
+
+test.concurrent('install uses OS line endings when lockfile doesn\'t exist', async (): Promise<void> => {
+  await runInstall({}, 'install-infers-line-endings-from-existing-lockfile',
+    async (config): Promise<void> => {
+      const lockfile = await promisify(fsNode.readFile)(path.join(config.cwd, 'yarn.lock'), 'utf8');
+      assert(lockfile.indexOf(os.EOL) >= 0);
+    });
+});

__tests__/fixtures/install/install-infers-line-endings-from-existing-lockfile/package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "left-pad": "1.1.1"
+  }
+}

src/cli/commands/install.js

@@ -544,7 +544,7 @@ export class Install {
     const loc = path.join(this.config.cwd, constants.LOCKFILE_FILENAME);
 
     // write lockfile
-    await fs.writeFile(loc, lockSource);
+    await fs.writeFilePreservingEol(loc, lockSource);
 
     this._logSuccessSaveLockfile();
   }

src/config.js

@@ -398,7 +398,7 @@ export default class Config {
           return file;
         }
       }
-      
+
       return null;
     });
   }
@@ -484,7 +484,7 @@ export default class Config {
         }
       }
 
-      await fs.writeFile(loc, JSON.stringify(object, null, indent || constants.DEFAULT_INDENT) + '\n');
+      await fs.writeFilePreservingEol(loc, JSON.stringify(object, null, indent || constants.DEFAULT_INDENT) + '\n');
     }
   }
 

src/registries/yarn-registry.js

@@ -114,6 +114,6 @@ export default class YarnRegistry extends NpmRegistry {
       this.homeConfig[key] = config[key];
     }
 
-    await fs.writeFile(this.homeConfigLoc, `${stringify(this.homeConfig)}\n`);
+    await fs.writeFilePreservingEol(this.homeConfigLoc, `${stringify(this.homeConfig)}\n`);
   }
 }

src/util/fs.js

@@ -7,6 +7,7 @@ import map from './map.js';
 
 const path = require('path');
 const fs = require('fs');
+const os = require('os');
 
 export const lockQueue = new BlockingQueue('fs lock');
 
@@ -454,3 +455,32 @@ export async function getFileSizeOnDisk(loc: string): Promise<number> {
 export function normalizeOS(body: string): string {
   return body.replace(/\r\n/g, '\n');
 }
+
+const cr = new Buffer('\r', 'utf8')[0];
+const lf = new Buffer('\n', 'utf8')[0];
+
+async function getEolFromFile(path: string) : Promise<string | void>  {
+  if (!(await exists(path))) {
+    return undefined;
+  }
+
+  const buffer = await readFileBuffer(path);
+
+  for (let i = 0; i < buffer.length; ++i) {
+    if (buffer[i] === cr) {
+      return '\r\n';
+    }
+    if (buffer[i] === lf) {
+      return '\n';
+    }
+  }
+  return undefined;
+}
+
+export async function writeFilePreservingEol(path: string, data: string) : Promise<void> {
+  const eol = (await getEolFromFile(path)) || os.EOL;
+  if (eol !== '\n') {
+    data = data.replace(/\n/g, eol);
+  }
+  await promisify(fs.writeFile)(path, data);
+}