ci: give generation its own job ahead of the checks

Author: ariesclark

.github/workflows/ci.yaml

@@ -14,10 +14,7 @@ on:
 name: CI
 
 jobs:
-  # Generated once here and handed to the checks below, so they neither repeat
-  # the generation nor disagree about what they are checking. The artifact name
-  # carries the language because a spec run shares one namespace across SDKs.
-  build:
+  generate:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v7
@@ -33,13 +30,33 @@ jobs:
 
       - run: bash ./generate.sh openapi-legacy.yaml
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v7
         with:
           name: generated-java
           path: .
+          include-hidden-files: true
+
+  build:
+    needs: generate
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        java: ['17', '21']
+    steps:
+      - uses: actions/download-artifact@v8
+        with:
+          name: generated-java
+
+      - uses: actions/setup-java@v5.7.0
+        with:
+          java-version: ${{ matrix.java }}
+          distribution: temurin
+          cache: maven
+
+      - run: mvn -B compile --no-transfer-progress
 
-  package:
-    needs: build
+  test:
+    needs: generate
     runs-on: ubuntu-latest
     strategy:
       matrix: