ci: build each release binary once and run the long pytest jobs as three shards

.github/workflows/integration-cassandra.yml

@@ -99,9 +99,33 @@ jobs:
         env:
           EXTENDDB_TEST_CASSANDRA: required
 
+  # One release build shared by the pytest and rust jobs; see integration.yml.
+  build-cassandra:
+    runs-on: extenddb_ubuntu-2404_4-core
+    timeout-minutes: 40
+    steps:
+      - uses: actions/checkout@v6
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+        with:
+          cache-on-failure: true
+          # Only pushes to main save, so other runs restore main's cache.
+          save-if: ${{ github.ref == 'refs/heads/main' }}
+      - name: Build release (cassandra backend)
+        run: cargo build --release --no-default-features --features cassandra
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02  # v4.6.2
+        with:
+          name: extenddb-cassandra
+          path: target/release/extenddb
+          if-no-files-found: error
+          retention-days: 1
+          # A re-run of a failed job uploads the same name again.
+          overwrite: true
+
   cassandra-pytest:
     runs-on: extenddb_ubuntu-2404_4-core
     timeout-minutes: 45
+    needs: build-cassandra
     services:
       cassandra:
         image: cassandra:4.1
@@ -119,12 +143,6 @@ jobs:
           --health-start-period 60s
     steps:
       - uses: actions/checkout@v6
-      - uses: dtolnay/rust-toolchain@stable
-      - uses: Swatinem/rust-cache@v2
-        with:
-          cache-on-failure: true
-          # Only pushes to main save, so other runs restore main's cache.
-          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Configure Cassandra authentication
         run: |
           docker exec ${{ job.services.cassandra.id }} sed -i \
@@ -147,14 +165,19 @@ jobs:
           python-version: "3.11"
       - name: Install Python dependencies
         run: pip install -r requirements.txt
-      - name: Build release (cassandra backend)
-        run: cargo build --release --no-default-features --features cassandra
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093  # v4.3.0
+        with:
+          name: extenddb-cassandra
+          path: target/release
+      # Artifacts do not keep file modes.
+      - run: chmod +x target/release/extenddb
       - name: Run Cassandra pytest suite
         run: devtools/run-cassandra-tests -- --pytest --comprehensive --parallel
 
   cassandra-rust:
     runs-on: extenddb_ubuntu-2404_4-core
     timeout-minutes: 45
+    needs: build-cassandra
     services:
       cassandra:
         image: cassandra:4.1
@@ -200,8 +223,13 @@ jobs:
           python-version: "3.11"
       - name: Install Python dependencies
         run: pip install -r requirements.txt
-      - name: Build release (cassandra backend)
-        run: cargo build --release --no-default-features --features cassandra
+      # After the cache restore, so a cached target/ cannot replace it.
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093  # v4.3.0
+        with:
+          name: extenddb-cassandra
+          path: target/release
+      # Artifacts do not keep file modes.
+      - run: chmod +x target/release/extenddb
       - name: Run Cassandra rust integration suite
         run: devtools/run-cassandra-tests -- --rust-integration
 

.github/workflows/integration-mongodb.yml

@@ -29,10 +29,8 @@ concurrency:
   cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 jobs:
-  mongodb-pytest:
-    # Dedicated ExtendDB runner group (Ubuntu 24.04, 4 vCPU / 16 GB, capped at
-    # 20 concurrent). ubuntu-latest is an Amazon-wide shared pool where our jobs
-    # waited 10-90 minutes to start (2026-09-29/30); see integration.yml.
+  # One release build shared by the pytest and rust jobs; see integration.yml.
+  build-mongodb:
     runs-on: extenddb_ubuntu-2404_4-core
     timeout-minutes: 40
     steps:
@@ -43,16 +41,59 @@ jobs:
           cache-on-failure: true
           # Only pushes to main save, so other runs restore main's cache.
           save-if: ${{ github.ref == 'refs/heads/main' }}
+      - name: Build release (mongodb backend)
+        run: cargo build --release --no-default-features --features mongodb-test-hooks
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02  # v4.6.2
+        with:
+          name: extenddb-mongodb
+          path: target/release/extenddb
+          if-no-files-found: error
+          retention-days: 1
+          # A re-run of a failed job uploads the same name again.
+          overwrite: true
+
+  mongodb-pytest:
+    # Dedicated ExtendDB runner group (Ubuntu 24.04, 4 vCPU / 16 GB, capped at
+    # 20 concurrent). ubuntu-latest is an Amazon-wide shared pool where our jobs
+    # waited 10-90 minutes to start (2026-09-29/30); see integration.yml.
+    runs-on: extenddb_ubuntu-2404_4-core
+    timeout-minutes: 40
+    needs: build-mongodb
+    # Three shards by test file; mongodb-integration checks that together
+    # they collected every test of the whole suite.
+    strategy:
+      fail-fast: false
+      matrix:
+        shard: [1, 2, 3]
+    env:
+      EXTENDDB_TEST_SHARD: ${{ matrix.shard }}/3
+    steps:
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v5
         with:
           python-version: "3.11"
       - name: Install Python dependencies
         run: pip install -r requirements.txt
-      - name: Build release (mongodb backend)
-        run: cargo build --release --no-default-features --features mongodb-test-hooks
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093  # v4.3.0
+        with:
+          name: extenddb-mongodb
+          path: target/release
+      # Artifacts do not keep file modes.
+      - run: chmod +x target/release/extenddb
       - name: Run MongoDB pytest suite
         run: devtools/run-mongodb-tests -- --pytest --comprehensive --parallel
 
+      # mongodb-integration checks these lists.
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02  # v4.6.2
+        if: always()
+        with:
+          name: shards-mongodb-pytest-${{ matrix.shard }}
+          path: discussions/shards/
+          if-no-files-found: warn
+          retention-days: 1
+          # A re-run of a failed job uploads the same name again.
+          overwrite: true
+
   # SnapshotEngine consistency check against a disposable replica set. The
   # tests build their own per-test scratch databases (snap<uuid>_cat and
   # _data) and drop them; they run in this job because it is the one that
@@ -107,6 +148,7 @@ jobs:
   mongodb-rust:
     runs-on: extenddb_ubuntu-2404_4-core
     timeout-minutes: 40
+    needs: build-mongodb
     steps:
       - uses: actions/checkout@v6
       - uses: dtolnay/rust-toolchain@stable
@@ -120,8 +162,13 @@ jobs:
           python-version: "3.11"
       - name: Install Python dependencies
         run: pip install -r requirements.txt
-      - name: Build release (mongodb backend)
-        run: cargo build --release --no-default-features --features mongodb-test-hooks
+      # After the cache restore, so a cached target/ cannot replace it.
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093  # v4.3.0
+        with:
+          name: extenddb-mongodb
+          path: target/release
+      # Artifacts do not keep file modes.
+      - run: chmod +x target/release/extenddb
       - name: Run MongoDB rust integration suite
         run: devtools/run-mongodb-tests -- --rust --rust-integration
 
@@ -152,3 +199,12 @@ jobs:
              [ "${{ needs.mongodb-snapshot.result }}" != "success" ]; then
             exit 1
           fi
+      # Fails unless the shards together collected every test of the whole
+      # suite exactly once, so a bad split cannot pass.
+      - uses: actions/checkout@v6
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093  # v4.3.0
+        with:
+          pattern: shards-mongodb-pytest-*
+          path: shards/mongodb-pytest
+      - name: Check the shards ran every test
+        run: python3 devtools/test-shards check shards/mongodb-pytest