Ability to opt-out of offline mirror

Configs are merged with configs in parent directories, so currently if a .yarnrc in a parent directory enables the offline mirror, all projects in child directories would also use the offline mirror.

This commit allows a child directory to opt-out of the offline mirror in their own .yarnrc with `yarn-offline-mirror false`.

Previously if you specified `false` you'd get an exception as false is parsed as boolean but it expects a string.

Also included tests verifying the existing .yarnrc merging behaviour (previously wasn't covered).

t14078443

__tests__/commands/_helpers.js

@@ -81,9 +81,21 @@ export async function run<T, R>(
 
   let cwd;
   if (fixturesLoc) {
-    const dir = path.join(fixturesLoc, name);
+    let parentDir = name;
+    let childDir = '';
+
+    // if the name is a path, copy the parent dir, then use the child dir as the cwd
+    // there's some existing tests which reference fixtures in a parent dir (../), so excluding those
+    const nameSepIndex = name.indexOf('/');
+    if (nameSepIndex !== -1 && name.indexOf('../') === -1) {
+      parentDir = name.slice(0, nameSepIndex);
+      childDir = name.slice(nameSepIndex);
+    }
+
+    const dir = path.join(fixturesLoc, parentDir);
     cwd = await fs.makeTempDir(path.basename(dir));
     await fs.copy(dir, cwd, reporter);
+    cwd += childDir;
   } else {
     // if fixture loc is not set then CWD is some empty temp dir
     cwd = await fs.makeTempDir();

__tests__/commands/install/integration.js

@@ -6,6 +6,7 @@ import {run as cache} from '../../../src/cli/commands/cache.js';
 import {run as check} from '../../../src/cli/commands/check.js';
 import * as constants from '../../../src/constants.js';
 import * as reporters from '../../../src/reporters/index.js';
+import {parse} from '../../../src/lockfile/wrapper.js';
 import {Install} from '../../../src/cli/commands/install.js';
 import Lockfile from '../../../src/lockfile/wrapper.js';
 import * as fs from '../../../src/util/fs.js';
@@ -809,6 +810,31 @@ test.concurrent('lockfile should be created when missing even if integrity match
   });
 });
 
+test.concurrent('offline mirror can be enabled from parent dir', (): Promise<void> => {
+  return runInstall({}, 'offline-mirror-configuration/enabled-from-parent', async (config, reporter) => {
+    const rawLockfile = await fs.readFile(path.join(config.cwd, 'yarn.lock'));
+    const lockfile = parse(rawLockfile);
+    expect(lockfile['[email protected]'].resolved).toEqual('mime-types-2.1.14.tgz#f7ef7d97583fcaf3b7d282b6f8b5679dab1e94ee');
+  });
+});
+
+test.concurrent('offline mirror can be enabled from parent dir, with merging of own .yarnrc', (): Promise<void> => {
+  return runInstall({}, 'offline-mirror-configuration/enabled-from-parent-merge', async (config, reporter) => {
+    const rawLockfile = await fs.readFile(path.join(config.cwd, 'yarn.lock'));
+    const lockfile = parse(rawLockfile);
+    expect(lockfile['[email protected]'].resolved).toEqual('mime-types-2.1.14.tgz#f7ef7d97583fcaf3b7d282b6f8b5679dab1e94ee');
+  });
+});
+
+test.concurrent('offline mirror can be disabled locally', (): Promise<void> => {
+  return runInstall({}, 'offline-mirror-configuration/disabled-locally', async (config, reporter) => {
+    const rawLockfile = await fs.readFile(path.join(config.cwd, 'yarn.lock'));
+    const lockfile = parse(rawLockfile);
+    expect(lockfile['[email protected]'].resolved)
+      .toEqual('https://registry.yarnpkg.com/mime-types/-/mime-types-2.1.14.tgz#f7ef7d97583fcaf3b7d282b6f8b5679dab1e94ee');
+  });
+});
+
 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> => {

__tests__/fixtures/install/offline-mirror-configuration/.yarnrc

@@ -0,0 +1 @@
+yarn-offline-mirror "./offline-mirror"

__tests__/fixtures/install/offline-mirror-configuration/disabled-locally/.yarnrc

@@ -0,0 +1 @@
+yarn-offline-mirror false

__tests__/fixtures/install/offline-mirror-configuration/disabled-locally/package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "mime-types": "2.1.14"
+  }
+}

__tests__/fixtures/install/offline-mirror-configuration/enabled-from-parent-merge/.yarnrc

@@ -0,0 +1 @@
+something else

__tests__/fixtures/install/offline-mirror-configuration/enabled-from-parent-merge/package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "mime-types": "2.1.14"
+  }
+}

__tests__/fixtures/install/offline-mirror-configuration/enabled-from-parent/package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "mime-types": "2.1.14"
+  }
+}

src/config.js

@@ -368,6 +368,10 @@ export default class Config {
 
       const registryMirrorPath = registry.config['yarn-offline-mirror'];
 
+      if (registryMirrorPath === false) {
+        return null;
+      }
+
       if (registryMirrorPath == null) {
         continue;
       }