don't duplicate M2 cache restoration

.github/actions/get-cache-keys/action.yml

@@ -30,7 +30,7 @@ runs:
       id: keys-factory
       run: |
         M2_CACHE_PREFIX='M2'
-        NODE_CACHE_PREFIX='node-modules'
+        NODE_CACHE_PREFIX='bun-store'
         ESLINT_CACHE_PREFIX='eslint'
         CYPRESS_CACHE_PREFIX='cypress'
         WEEK_OF_YEAR=$(/bin/date "+%G-%V")

.github/actions/prepare-frontend/action.yml

@@ -8,6 +8,13 @@ inputs:
     description: "Whether to patch frontend dependencies with patch-package."
     required: true
     default: "true"
+  restore-m2-cache:
+    description: |
+      Whether to restore the M2 (Clojure dependency) cache. Only needed by jobs that run Clojure -- shadow-cljs, for
+      example. Set this to "false" when the job also uses `prepare-backend`, which restores a superset of this cache
+      under the same key; restoring it twice just downloads ~650MB for nothing.
+    required: false
+    default: "true"
 runs:
   using: "composite"
   steps:
@@ -21,6 +28,7 @@ runs:
       id: get-cache-keys
 
     - name: Restore M2 cache
+      if: inputs.restore-m2-cache == 'true'
       uses: actions/cache/restore@v5
       with:
         path: |
@@ -38,29 +46,24 @@ runs:
         echo "dir=$BUN_CACHE_DIR" >> "$GITHUB_OUTPUT"
       shell: bash
 
-    - name: Restore node_modules cache
+    - name: Restore bun store cache
       uses: actions/cache/restore@v5
-      id: node-modules-cache
+      id: bun-store-cache
       with:
-        path: |
-          ${{ steps.bun-cache.outputs.dir }}
-          node_modules
+        path: ${{ steps.bun-cache.outputs.dir }}
         key: ${{ steps.get-cache-keys.outputs.node-cache-key }}
         restore-keys: |
           ${{ steps.get-cache-keys.outputs.node-restore-key }}
 
     # postinstall lifecycle hook can be dangerous in CI so we only run it locally (see package.json)
     # If a job wants to patch packages, it does so explicitly in the CI. This setting is opt-out.
-    # For example, we never want to cache node_modules with patches already applied so cache-generator.yml skips that step.
     - name: Clean install
-      # Remove the restored node_modules before installing. The os-week cache can
-      # carry a stale tree (for example a different React major), and
-      # `--frozen-lockfile` alone does not prune it. Rebuilding from the cached bun
-      # store gives an exact, lockfile-correct node_modules with no extra download.
+      # Always build node_modules from scratch out of the cached bun store to avoid stale dependencies.
       run: |
         rm -rf node_modules
         bun install --frozen-lockfile
       shell: bash
+
     - name: Patch frontend dependencies
       if: inputs.apply-patches == 'true'
       run: bun run patch-package

.github/workflows/backend-cloverage.yml

@@ -42,6 +42,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 
@@ -90,6 +93,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 

.github/workflows/backend.yml

@@ -177,6 +177,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
         with:

.github/workflows/cache-generator.yml

@@ -1,16 +1,18 @@
 # This workflow is the single source of truth for generating and updating various caches used by our CI pipeline.
-# It sets the fresh cache each Monday but provides a manual trigger to update it on-demand.
+# It refreshes the cache every night but provides a manual trigger to update it on-demand.
 #
 # All other jobs only restore from this cache; *they never update it*!
 # They should always use `actions/cache/restore@vX` because `actions/cache@vX` would attempt to save the cache.
 #
 # Our agreed-upon strategy is to use a deterministic cache key based on the week of the year.
 # Jobs can utilize the prior week's cache if the current week's cache is not found.
+# The key only rolls over weekly; the nightly run replaces the contents stored under the current
+# week's key, so a dependency added on Tuesday does not have to wait until Monday to be cached.
 #
 #
 # PRINCIPLES:
 #   - The cache is never wrong!
-#   - Caches are immutable once created.
+#   - Caches are immutable to every job except this one -- only this workflow deletes and rewrites them.
 #   - Caches are for speeding up builds, not for correctness.
 #   - It is faster to download a large cache than to re-resolve missing dependencies.
 #
@@ -30,7 +32,7 @@ name: Cache Generator
 
 on:
   schedule:
-    - cron: "0 3 * * 1" # Mondays at 03:00 UTC
+    - cron: "0 3 * * *" # Daily at 03:00 UTC
   workflow_dispatch: # manually update the cache
 
 concurrency:
@@ -131,12 +133,10 @@ jobs:
           key: ${{ env.M2_CACHE_KEY }}
 
       # Frontend preparation and caches
-      # `prepare-frontend` action (1) prepares Node.js and (2) fetches the node_modules cache if it exists.
-      # It then (3) runs `bun install --frozen-lockfile` which ensures the local cache is fully populated.
-      # IMPORTANT: Caching node_modules after patches are already applied will break any PR that attempts to either:
-      #   - upgrade a patched library
-      #   - change a patch
-      # Hence why we explicitly exclude patches from the cache (controlled by the `apply-patches` action input).
+      # `prepare-frontend` action (1) prepares Node.js and (2) fetches the bun store cache if it exists.
+      # It then (3) runs `bun install --frozen-lockfile` which ensures the local store is fully populated.
+      # Patches are applied to `node_modules`, never to the store, so there is nothing patch-shaped to leak
+      # into the cache -- but we still skip patching here because this job has no use for a patched tree.
       - name: Install front-end dependencies
         uses: ./.github/actions/prepare-frontend
         with:
@@ -157,12 +157,12 @@ jobs:
           bun run cypress verify
         shell: bash
 
-      - name: Update node_modules cache
+      # Only the bun store is cached. `prepare-frontend` rebuilds node_modules from it on every job, so
+      # shipping the tree itself around just costs download and extraction time everywhere it is restored.
+      - name: Update bun store cache
         uses: ./.github/actions/update-cache
         with:
-          path: |
-            ${{ steps.bun-cache.outputs.dir }}
-            node_modules
+          path: ${{ steps.bun-cache.outputs.dir }}
           key: ${{ env.NODE_CACHE_KEY }}
 
       - name: Update Cypress cache

.github/workflows/chromatic.yml

@@ -38,6 +38,9 @@ jobs:
           fetch-depth: 0
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Compile CLJS

.github/workflows/cljs.yml

@@ -36,6 +36,9 @@ jobs:
     - uses: actions/checkout@v6
     - name: Prepare front-end environment
       uses: ./.github/actions/prepare-frontend
+      with:
+        # M2 cache is restored by `prepare-backend`
+        restore-m2-cache: "false"
     - name: Prepare back-end environment
       uses: ./.github/actions/prepare-backend
     - name: Run Cljs tests

.github/workflows/coverage.yml

@@ -14,6 +14,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Run frontend unit tests

.github/workflows/e2e-coverage-manifest.yml

@@ -36,6 +36,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       # build.clj forwards INSTRUMENT_COVERAGE to the rspack build, so only the

.github/workflows/e2e-coverage-shard.yml

@@ -64,6 +64,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Prepare Cypress environment

.github/workflows/e2e-stress-test-flake-fix.yml

@@ -179,6 +179,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 

.github/workflows/e2e-test.yml

@@ -112,6 +112,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 

.github/workflows/embedding-sdk-component-tests.yml

@@ -66,6 +66,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 
@@ -216,6 +219,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 

.github/workflows/embedding-sdk-host-sample-apps-tests.yml

@@ -412,6 +412,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 

.github/workflows/embedding-sdk-package-build.yml

@@ -16,6 +16,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Build Embedding SDK package

.github/workflows/frontend-unit-test-stress-test-flake-fix.yml

@@ -49,6 +49,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Build cljs

.github/workflows/frontend.yml

@@ -47,6 +47,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
 
@@ -78,6 +81,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - run: bun run build-pure:cljs
@@ -101,6 +107,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Resolve current job id

.github/workflows/lint.yml

@@ -46,6 +46,8 @@ jobs:
           needs.files-changed.outputs.yaml == 'true' ||
           needs.files-changed.outputs.openapi == 'true'
         uses: ./.github/actions/prepare-frontend
+        with:
+          restore-m2-cache: "false"
 
       # Always required by whitespace linter, also used by OpenAPI spec validation
       - name: Setup backend env
@@ -99,6 +101,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Install xgettext if necessary

.github/workflows/loki-stress-test-flake-fix.yml

@@ -142,6 +142,9 @@ jobs:
 
       - name: Prepare frontend environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
 
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend

.github/workflows/loki-update.yml

@@ -17,6 +17,9 @@ jobs:
 
       - name: Prepare frontend environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
 
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend

.github/workflows/loki.yml

@@ -44,6 +44,9 @@ jobs:
 
       - name: Prepare frontend environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
 
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend

.github/workflows/pre-release.yml

@@ -186,6 +186,9 @@ jobs:
           snowplow: true
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Compile CLJS

.github/workflows/release-embedding-sdk.yml

@@ -346,6 +346,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
 
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
@@ -369,6 +372,9 @@ jobs:
 
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
 
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend

.github/workflows/run-tests.yml

@@ -105,6 +105,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Compile CLJS
@@ -130,6 +133,9 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: Build static-viz frontend

.github/workflows/translation-update.yml

@@ -28,6 +28,9 @@ jobs:
           token: ${{ secrets.METABASE_AUTOMATION_USER_TOKEN }}
       - name: Prepare front-end environment
         uses: ./.github/actions/prepare-frontend
+        with:
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
       - name: install gettext

.github/workflows/uberjar.yml

@@ -144,6 +144,8 @@ jobs:
         uses: ./.github/actions/prepare-frontend
         with:
           node-version: "${{ needs.get-build-requirements.outputs.node_version || '22' }}"
+          # M2 cache is restored by `prepare-backend`
+          restore-m2-cache: "false"
       - name: Prepare back-end environment
         uses: ./.github/actions/prepare-backend
         with: