Test PR Workflow with sparse checkout (typst#1229)

.github/workflows/deploy.yml

@@ -13,7 +13,7 @@ jobs:
     name: Deploy
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           # Download the whole history for the package timestamps
           fetch-depth: 0

.github/workflows/test.yml

@@ -3,14 +3,13 @@ name: Test
 on:
   push:
     branches: ['*', '!main']
-  pull_request: {}
 
 jobs:
   test:
     name: Test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2
         with:

.github/workflows/test_pr.yml

@@ -0,0 +1,51 @@
+name: Test PR
+on:
+  pull_request: {}
+
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Extract package names and versions from changed files
+        id: extract_package
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const { data: files } = await github.rest.pulls.listFiles({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: context.payload.pull_request.number,
+            });
+
+            const packages = new Set();
+            files.forEach(file => {
+              const match = file.filename.match(/^packages\/preview\/([^\/]+)\/([^\/]+)\//);
+              if (match) {
+                packages.add(`${match[1]}/${match[2]}`);
+              }
+            });
+
+            let sparseCheckoutPaths;
+            if (packages.size === 0) {
+              sparseCheckoutPaths = "packages/";
+            } else {
+              sparseCheckoutPaths = Array.from(packages).map(pkg => `packages/preview/${pkg}/`).join('\n');
+            }
+            core.setOutput('sparse_checkout_paths', sparseCheckoutPaths);
+
+      - uses: actions/checkout@v4
+        with:
+          sparse-checkout: |
+            ${{ steps.extract_package.outputs.sparse_checkout_paths }}
+            bundler/
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: bundler
+
+      - name: Build bundler
+        run: cargo build --release --manifest-path bundler/Cargo.toml
+
+      - name: Test packaging
+        run: bundler/target/release/bundler