fix(ci): restore dist cache before artifact builds (#89169)

.github/workflows/ci.yml

@@ -605,7 +605,19 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-build-all-v3-
 
+      - name: Restore dist build cache
+        id: dist_build_cache
+        uses: actions/cache/restore@v5
+        with:
+          path: |
+            dist/
+            dist-runtime/
+            extensions/*/src/host/**/.bundle.hash
+            extensions/*/src/host/**/*.bundle.js
+          key: ${{ runner.os }}-dist-build-${{ needs.preflight.outputs.checkout_revision }}
+
       - name: Build dist
+        if: steps.dist_build_cache.outputs.cache-hit != 'true'
         env:
           NODE_OPTIONS: --max-old-space-size=8192
         run: pnpm build:ci-artifacts
@@ -614,14 +626,6 @@ jobs:
         if: needs.preflight.outputs.run_control_ui_i18n == 'true'
         run: pnpm ui:i18n:check
 
-      - name: Cache dist build
-        uses: actions/cache@v5
-        with:
-          path: |
-            dist/
-            dist-runtime/
-          key: ${{ runner.os }}-dist-build-${{ needs.preflight.outputs.checkout_revision }}
-
       - name: Pack built runtime artifacts
         run: tar --posix -cf dist-runtime-build.tar.zst --use-compress-program zstdmt dist dist-runtime
 
@@ -751,6 +755,18 @@ jobs:
           done
           exit "$failures"
 
+      - name: Save dist build cache
+        if: steps.dist_build_cache.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v5
+        continue-on-error: true
+        with:
+          path: |
+            dist/
+            dist-runtime/
+            extensions/*/src/host/**/.bundle.hash
+            extensions/*/src/host/**/*.bundle.js
+          key: ${{ steps.dist_build_cache.outputs.cache-primary-key }}
+
       - name: Upload gateway watch regression artifacts
         if: always() && needs.preflight.outputs.run_check_additional == 'true'
         uses: actions/upload-artifact@v7

test/scripts/ci-workflow-guards.test.ts

@@ -146,6 +146,35 @@ describe("ci workflow guards", () => {
     expect(buildArtifactSteps.some((step) => step.run === "pnpm ui:build")).toBe(false);
   });
 
+  it("restores the dist build cache before building and saves only cache misses", () => {
+    const workflow = readCiWorkflow();
+    const buildArtifactSteps = workflow.jobs["build-artifacts"].steps;
+    const stepNames = buildArtifactSteps.map((step) => step.name);
+    const restoreStep = buildArtifactSteps.find((step) => step.name === "Restore dist build cache");
+    const buildDistStep = buildArtifactSteps.find((step) => step.name === "Build dist");
+    const saveStep = buildArtifactSteps.find((step) => step.name === "Save dist build cache");
+
+    expect(stepNames.indexOf("Restore dist build cache")).toBeLessThan(
+      stepNames.indexOf("Build dist"),
+    );
+    expect(stepNames.indexOf("Build dist")).toBeLessThan(
+      stepNames.indexOf("Pack built runtime artifacts"),
+    );
+    expect(stepNames.indexOf("Run built artifact checks")).toBeLessThan(
+      stepNames.indexOf("Save dist build cache"),
+    );
+    expect(restoreStep.uses).toBe("actions/cache/restore@v5");
+    expect(buildDistStep.if).toBe("steps.dist_build_cache.outputs.cache-hit != 'true'");
+    expect(saveStep.uses).toBe("actions/cache/save@v5");
+    expect(saveStep.if).toBe("steps.dist_build_cache.outputs.cache-hit != 'true'");
+    expect(saveStep.with.key).toBe("${{ steps.dist_build_cache.outputs.cache-primary-key }}");
+    expect(restoreStep.with.path).toContain("dist/");
+    expect(restoreStep.with.path).toContain("dist-runtime/");
+    expect(restoreStep.with.path).toContain("extensions/*/src/host/**/.bundle.hash");
+    expect(restoreStep.with.path).toContain("extensions/*/src/host/**/*.bundle.js");
+    expect(buildArtifactSteps.map((step) => step.name)).not.toContain("Cache dist build");
+  });
+
   it("gives quiet Node test shards enough no-output runway", () => {
     const workflow = readCiWorkflow();
     const nodeTestJob = workflow.jobs["checks-node-core-test-nondist-shard"];