test: simplify CI workflow to minimal version for debugging

Strip down to single echo job to identify what's causing GitHub Actions rejection.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: derrickburns

.github/workflows/ci.yml

@@ -20,210 +20,12 @@ env:
   SBT_OPTS: "-Xms2g -Xmx4g -XX:+UseG1GC -Dsbt.log.noformat=true"
 
 jobs:
-  # Job 0: Linting and Code Style (fast gate)
-  lint:
+  # Job 0: Simple test to verify workflow is accepted
+  test-minimal:
     runs-on: ubuntu-latest
-    name: Lint & Style Check
+    name: Minimal Test
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ env.JAVA_VERSION }}
-          cache: sbt
-      - uses: sbt/setup-sbt@v1
-      - name: Check Formatting and Style
-        run: |
-          sbt ++${{ env.SCALA_213 }} scalafmtCheckAll
-          sbt ++${{ env.SCALA_213 }} scalastyle
+      - name: Echo test
+        run: echo "CI workflow is running successfully"
 
-  # Job 1: Build once (produce 2.12 & 2.13 jars for reuse)
-  build:
-    runs-on: ubuntu-latest
-    needs: lint
-    name: Build JARs (2.12 & 2.13)
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ env.JAVA_VERSION }}
-          cache: sbt
-      - uses: sbt/setup-sbt@v1
-      - name: Package 2.12 (Spark ${{ env.DEFAULT_SPARK }})
-        run: sbt ++${{ env.SCALA_212 }} -Dspark.version=${{ env.DEFAULT_SPARK }} clean package
-      - name: Package 2.13 (Spark ${{ env.DEFAULT_SPARK }})
-        run: sbt ++${{ env.SCALA_213 }} -Dspark.version=${{ env.DEFAULT_SPARK }} clean package
-      - name: Upload JARs
-        uses: actions/upload-artifact@v4
-        with:
-          name: jars
-          path: |
-            target/scala-2.12/*.jar
-            target/scala-2.13/*.jar
-          if-no-files-found: error
-
-  # Job 2: Core JVM tests across matrix (re-compiles per combo; ok)
-  test-jvm:
-    runs-on: ubuntu-latest
-    needs: build
-    strategy:
-      fail-fast: false
-      matrix:
-        scala-version: [ '2.13.14', '2.12.18' ]
-        spark-version: [ '3.4.3', '3.5.1' ]
-        include:
-          # Force Java 17 for Spark 3.5/3.4
-          - java-version: '17'
-        exclude:
-          # Spark 3.4 typically ships with Scala 2.12 artifacts
-          - scala-version: '2.13.14'
-            spark-version: '3.4.3'
-    name: Test (Scala ${{ matrix.scala-version }}, Spark ${{ matrix.spark-version }})
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ matrix.java-version }}
-          cache: sbt
-      - uses: sbt/setup-sbt@v1
-      - name: Run All JVM Tests
-        run: sbt ++${{ matrix.scala-version }} -Dspark.version=${{ matrix.spark-version }} test
-      - name: Preserve test reports
-        if: always()
-        run: |
-          mkdir -p artifacts/test-reports/${{ matrix.scala-version }}_${{ matrix.spark-version }}
-          (test -d target/test-reports && cp -r target/test-reports/* artifacts/test-reports/${{ matrix.scala-version }}_${{ matrix.spark-version }}/) || true
-      - uses: actions/upload-artifact@v4
-        if: always()
-        with:
-          name: test-reports-${{ matrix.scala-version }}-${{ matrix.spark-version }}
-          path: artifacts/test-reports/${{ matrix.scala-version }}_${{ matrix.spark-version }}
-
-  # Job 3: Python smoke test (downloads jar built once; uses non-SE divergence)
-  test-python:
-    runs-on: ubuntu-latest
-    needs: build
-    name: Python Smoke Test (PySpark ${{ env.PYSPARK_PIN }})
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: "3.11"
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ env.JAVA_VERSION }}
-      - name: Download JARs
-        uses: actions/download-artifact@v4
-        with:
-          name: jars
-          path: jars
-      - name: Install PySpark
-        run: python -m pip install --upgrade pip && pip install pyspark==${{ env.PYSPARK_PIN }}
-      - name: Run smoke (local[*], non-SE)
-        run: |
-          JAR_212=$(ls jars/*scala-2.12*.jar | head -n1)
-          test -f "$JAR_212"
-          spark-submit --jars "$JAR_212" python/smoke_test.py
-
-  # Job 4: Run examples via runMain with assertions
-  examples-run:
-    runs-on: ubuntu-latest
-    needs: build
-    name: Examples (runMain)
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ env.JAVA_VERSION }}
-          cache: sbt
-      - uses: sbt/setup-sbt@v1
-      - name: Run examples via runMain
-        run: |
-          sbt ++${{ env.SCALA_213 }} -Dspark.version=${{ env.DEFAULT_SPARK }} "runMain examples.BisectingExample"
-          sbt ++${{ env.SCALA_213 }} -Dspark.version=${{ env.DEFAULT_SPARK }} "runMain examples.XMeansExample"
-          sbt ++${{ env.SCALA_213 }} -Dspark.version=${{ env.DEFAULT_SPARK }} "runMain examples.SoftKMeansExample"
-
-  # Job 5: Cross-version persistence check (save on 3.4, load on 3.5; and reverse)
-  persistence-cross:
-    runs-on: ubuntu-latest
-    needs: build
-    name: Persistence Cross-Version (3.4 ↔ 3.5)
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ env.JAVA_VERSION }}
-          cache: sbt
-      - uses: sbt/setup-sbt@v1
-
-      - name: Save with Spark 3.4.x
-        run: sbt ++${{ env.SCALA_213 }} -Dspark.version=3.4.3 "runMain examples.PersistenceRoundTrip save ./tmp_model_34"
-
-      - name: Load with Spark 3.5.x
-        run: sbt ++${{ env.SCALA_213 }} -Dspark.version=${{ env.DEFAULT_SPARK }} "runMain examples.PersistenceRoundTrip load ./tmp_model_34"
-
-      - name: Save with Spark 3.5.x
-        run: sbt ++${{ env.SCALA_213 }} -Dspark.version=${{ env.DEFAULT_SPARK }} "runMain examples.PersistenceRoundTrip save ./tmp_model_35"
-
-      - name: Load with Spark 3.4.x
-        run: sbt ++${{ env.SCALA_213 }} -Dspark.version=3.4.3 "runMain examples.PersistenceRoundTrip load ./tmp_model_35"
-
-  # Job 6: Perf sanity (SE and non-SE) — logs perf_sanity_seconds=...
-  perf-sanity:
-    runs-on: ubuntu-latest
-    needs: build
-    name: Perf Sanity
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ env.JAVA_VERSION }}
-          cache: sbt
-      - uses: sbt/setup-sbt@v1
-      - name: Run Perf Sanity (SE & KL)
-        run: |
-          sbt ++${{ env.SCALA_213 }} -Dspark.version=${{ env.DEFAULT_SPARK }} "testOnly *PerfSanitySuite"
-      - name: Surface perf metrics
-        run: |
-          grep -E 'perf_sanity_seconds=' target/scala-2.13/test-reports/* || true
-
-  # Job 7: Coverage (unchanged, runs once)
-  coverage:
-    runs-on: ubuntu-latest
-    needs: build
-    name: Code Coverage
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
-        with:
-          distribution: temurin
-          java-version: ${{ env.JAVA_VERSION }}
-          cache: sbt
-      - uses: sbt/setup-sbt@v1
-      - name: Generate Coverage Report
-        run: sbt ++${{ env.SCALA_212 }} -Dspark.version=${{ env.DEFAULT_SPARK }} coverage test coverageReport
-      - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v4
-        with:
-          file: ./target/scala-2.12/scoverage-report/scoverage.xml
-          fail_ci_if_error: false
-
-  # Final gate: only reports success if all validations pass
-  release-ready:
-    runs-on: ubuntu-latest
-    needs:
-      - lint
-      - test-jvm
-      - test-python
-      - examples-run
-      - persistence-cross
-      - perf-sanity
-      - coverage
-    steps:
-      - run: echo "All validations passed."