feat: Support for yarn berry (#99)

.changeset/cool-actors-visit.md

@@ -0,0 +1,5 @@
+---
+"secco": minor
+---
+
+Support Yarn Berry (currently v3 & v4) by modyfing the .yarnrc.yml file inside the destination before trying to install packages from the local Verdaccio registry

.github/workflows/integration-testing.yml

@@ -9,20 +9,27 @@ jobs:
       matrix:
         pm:
           - name: npm
+            displayName: npm
             version: 10.8.1
           - name: pnpm
+            displayName: pnpm
             version: 9.4.0
           - name: yarn
+            displayName: yarn (classic)
             version: 1.22.22
+          - name: yarn
+            displayName: yarn (berry)
+            version: 4.3.1
           - name: bun
+            displayName: bun
             version: 1.1.17
-    name: ${{ matrix.pm.name }}
+    name: ${{ matrix.pm.displayName }}
     steps:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install dependencies
         uses: ./.github/actions/pnpm-install
-      - name: Install Bun
+      - name: Install Bun (optional)
         uses: oven-sh/setup-bun@v2
         if: ${{ matrix.pm.name == 'bun' }}
       - uses: actions/download-artifact@v4

src/verdaccio/install-packages.ts

@@ -1,4 +1,5 @@
 import process from 'node:process'
+import { execa } from 'execa'
 import { detectPackageManager } from 'nypm'
 import { logger } from '../utils/logger'
 import type { PromisifiedSpawnArgs } from '../utils/promisified-spawn'
@@ -31,13 +32,13 @@ If you have control over the destination, manually add the "packageManager" key
   let externalRegistry = false
   let env: NodeJS.ProcessEnv = {}
 
-  // The combination of name and majorVersion allows us to detect yarn 3
-  if (name === 'yarn' && majorVersion === '3')
+  // Yarn Berry
+  if (name === 'yarn' && (majorVersion === '3' || majorVersion === '4')) {
     externalRegistry = true
-    // TODO(feature): Handle externalRegistry case by detecting yarn 2/3 and modify yarn config
-    // We need to set programatically:
-    // yarn config set npmRegistryServer http://localhost:4873
-    // unsafeHttpWhitelist:\n - "localhost"
+
+    await execa`yarn config set npmRegistryServer ${REGISTRY_URL}`
+    await execa`yarn config set unsafeHttpWhitelist --json ["localhost"]`
+  }
 
   if (name === 'bun') {
     externalRegistry = true