From 8b482521e0369c678e2c9aba4b6d50936f70d29c Mon Sep 17 00:00:00 2001
From: "Benjamin R. J. Schwedler" <ben@posit.co>
Date: Tue, 16 Jun 2026 17:04:19 -0500
Subject: [PATCH] Seed CDN cache from matrix job into build jobs

requests-cache uses a filesystem backend at /tmp/bakery_cache/ with
deterministic blake2b keys derived from the request URL. The matrix
job's CDN lookups populate this cache, but each subsequent job runs
on a fresh runner and re-queries the CDN independently.

If the daily CDN updates between the matrix step and a build/merge
step, the resolved version changes and the --image-version filter no
longer matches, producing a "no targets" failure (issue #304).

Upload the populated cache as a run-scoped artifact after the matrix
step and restore it before each bakery invocation that follows. The
restore uses continue-on-error so production builds (no dev versions,
no CDN cache) degrade gracefully rather than failing.
---
 .github/workflows/bakery-build-native.yml | 20 ++++++++++++++++++++
 .github/workflows/bakery-build-pr.yml     | 14 ++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/.github/workflows/bakery-build-native.yml b/.github/workflows/bakery-build-native.yml
index 2a564ee6..114ea044 100644
--- a/.github/workflows/bakery-build-native.yml
+++ b/.github/workflows/bakery-build-native.yml
@@ -188,6 +188,13 @@ jobs:
           echo "platform_matrix=$(echo "$result" | jq --compact-output .)" >> "$GITHUB_OUTPUT"
           echo "image_matrix=$(echo "$result" | jq --compact-output '[.[].image] | unique')" >> "$GITHUB_OUTPUT"
 
+      - name: Upload CDN cache
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: bakery-cdn-cache
+          path: /tmp/bakery_cache/
+          if-no-files-found: ignore
+
   build-test:
     name: "Build/Test ${{ matrix.img.image }}:${{ matrix.img.version }} (${{ matrix.img.platform }})"
     permissions:
@@ -294,6 +301,12 @@ jobs:
           else
             echo "dev-spec=" >> "$GITHUB_OUTPUT"
           fi
+      - name: Restore CDN cache
+        continue-on-error: true
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c  # v8.0.1
+        with:
+          name: bakery-cdn-cache
+          path: /tmp/bakery_cache/
       - name: Build
         env:
           GIT_SHA: ${{ github.sha }}
@@ -474,6 +487,13 @@ jobs:
             echo "dev-spec=" >> "$GITHUB_OUTPUT"
           fi
 
+      - name: Restore CDN cache
+        continue-on-error: true
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c  # v8.0.1
+        with:
+          name: bakery-cdn-cache
+          path: /tmp/bakery_cache/
+
       - name: Publish
         env:
           GIT_SHA: ${{ github.sha }}
diff --git a/.github/workflows/bakery-build-pr.yml b/.github/workflows/bakery-build-pr.yml
index 16f249bc..3889f977 100644
--- a/.github/workflows/bakery-build-pr.yml
+++ b/.github/workflows/bakery-build-pr.yml
@@ -121,6 +121,13 @@ jobs:
           result=$(bakery ci matrix --quiet --dev-versions "$DEV_VERSIONS" --matrix-versions "$MATRIX_VERSIONS" --exclude platform --context "$BAKERY_CONTEXT")
           echo "versions_matrix=$(echo "$result" | jq --compact-output .)" >> "$GITHUB_OUTPUT"
 
+      - name: Upload CDN cache
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: bakery-cdn-cache
+          path: /tmp/bakery_cache/
+          if-no-files-found: ignore
+
   build-test:
     name: "Build/Test ${{ matrix.img.image }}:${{ matrix.img.version }} (${{ matrix.img.platform }})"
     needs:
@@ -180,6 +187,13 @@ jobs:
           PLATFORM=${BUILD_PLATFORM#linux/}
           echo "platform=$PLATFORM" >> "$GITHUB_OUTPUT"
 
+      - name: Restore CDN cache
+        continue-on-error: true
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c  # v8.0.1
+        with:
+          name: bakery-cdn-cache
+          path: /tmp/bakery_cache/
+
       - name: Build
         env:
           IS_FORK: ${{ needs.detect.outputs.is-fork }}