Enable corepack if packageManager is defined

.github/actions/base-setup/action.yml

@@ -73,6 +73,11 @@ runs:
       id: yarn-cache-dir-path
       shell: bash
       run: |
+        # Enable corepack if the project defines packageManager
+        if [ -f package.json ]; then
+          export HAS_PKG_MANAGER=$(grep -e \"packageManager\"\: package.json)
+          if [ ! -z "$HAS_PKG_MANAGER" ]; then corepack enable; fi
+        fi
         CACHE_DIR=$(yarn config get cacheFolder)
         [[ "$CACHE_DIR" == "undefined" ]] && CACHE_DIR=$(yarn cache dir)
         echo "dir=$CACHE_DIR" >> $GITHUB_OUTPUT

.github/workflows/tests.yml

@@ -62,7 +62,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
+      - uses: ./.github/actions/base-setup
       - name: Run Linters
         run: |
           hatch run typing:test
@@ -162,6 +162,9 @@ jobs:
         run: |
           mkdir -p ${TEST_FOLDER}/tests/example.spec.ts-snapshots
           pushd ${TEST_FOLDER}
+
+          # Prevent yarn to look up in the folder hierarchy
+          touch yarn.lock
           yarn init -yp
           yarn add -D @playwright/test
           cat package.json | jq '. += {"scripts": {"start": "echo starting...", "test:update": "yarn playwright test -u"}}' > new_package.json
@@ -205,6 +208,9 @@ jobs:
         run: |
           mkdir -p ${TEST_FOLDER}/tests/example.spec.ts-snapshots
           pushd ${TEST_FOLDER}
+
+          # Prevent yarn to look up in the folder hierarchy
+          touch yarn.lock
           yarn init -yp
           yarn add -D @playwright/test
           cat package.json | jq '. += {"scripts": {"test:update": "yarn playwright test -u"}}' > new_package.json

package.json

@@ -1,5 +1,6 @@
 {
     "name": "@jupyterlab/maintainer-tools",
     "version": "0.25.9",
-    "private": true
+    "private": true,
+    "packageManager": "yarn@3.5.0"
 }