Adding a pre-release workflow to test huggingface_hub (#242)

Since changes to xet-core and hf-xet can break huggingface_hub, we're
adding automation to test the whole cross-platform huggingface_hub test
suite against our RC builds.

This uses the same trick that huggingface_hub uses with the
transformers, datasets, and diffusers libraries. It creates a ci branch
on huggingface_hub which triggers the cross-platform huggingface_hub
test suite.

Author: bpronan

.github/workflows/pre-release-testing.yml

@@ -0,0 +1,81 @@
+name: hf-xet prerelease testing
+# This workflow is triggered when a new pre-release build is triggered by the release workflow. 
+
+on:
+  push:
+    tags:
+      - v*rc*
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "Tag to test (e.g., v1.0.3rc2)"
+        required: true
+jobs:
+  trigger_rc_testing:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        target-repo: ["huggingface_hub"]
+
+    steps:
+      - name: Determine version from tag
+        id: get-version
+        run: |
+          if [[ "${{ github.event_name }}" == "workflow_dispatch" ]]; then
+            echo "VERSION=${{ inputs.tag }}" >> $GITHUB_OUTPUT
+          else
+            echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Checkout target repo
+        uses: actions/checkout@v4
+        with:
+          repository: huggingface/${{ matrix.target-repo }}
+          path: ${{ matrix.target-repo }}
+          token: ${{ secrets.TOKEN_HUGGINGFACE_HUB_AUTO_BY_XET }}
+
+      - name: Configure Git
+        run: |
+          cd ${{ matrix.target-repo }}
+          git config user.name "Hugging Face Bot (Xet RC Testing)"
+          git config user.email "[email protected]"
+
+      - name: Wait for prerelease to be out on PyPI
+        run: |
+          VERSION=${{ steps.get-version.outputs.VERSION }}
+          echo "Waiting for hf_xet==${VERSION} to be available on PyPI"
+          while ! pip install hf_xet==${VERSION}; do
+            echo "hf_xet==${VERSION} not available yet, retrying in 15s"
+            sleep 15
+          done
+
+      - name: Create test branch and update dependencies
+        id: create-pr
+        run: |
+          cd ${{ matrix.target-repo }}
+          VERSION=${{ steps.get-version.outputs.VERSION }}
+          BRANCH_NAME="ci-test-hf-xet-${VERSION}-release"
+
+          # Create and checkout new branch
+          git checkout -b $BRANCH_NAME
+
+          # Update dependencies using sed
+          sed -i -E "s/\"hf_xet>=*\"/\"hf_xet==${VERSION}\"/" setup.py
+          git add setup.py
+
+          # Any line with `uv pip install --prerelease=allow` in the `.github/` folder must be updated with `--prerelease=allow` flag
+          find .github/workflows/ -type f -exec sed -i 's/uv pip install /uv pip install --prerelease=allow /g' {} +
+          git add .github/workflows/
+
+          # Commit and push changes
+          git --no-pager diff --staged
+          git commit -m "Test hfh ${VERSION}"
+          git push --set-upstream origin $BRANCH_NAME
+
+      - name: Print URLs for manual check
+        run: |
+          VERSION=${{ steps.get-version.outputs.VERSION }}
+          echo "https://github.com/xet-core/${{ matrix.target-repo }}/actions"
+          echo "https://github.com/xet-core/${{ matrix.target-repo }}/compare/main...${BRANCH_NAME}"