chore(ci): Avoid writing to cache in workflows triggered by the merge queue

.github/workflows/publish.yml

@@ -79,7 +79,8 @@ jobs:
           echo "SDKROOT=$(xcrun -sdk macosx$(sw_vers -productVersion) --show-sdk-path)" >> $GITHUB_ENV
           echo "MACOSX_DEPLOYMENT_TARGET=$(xcrun -sdk macosx$(sw_vers -productVersion) --show-sdk-platform-version)" >> $GITHUB_ENV
 
-      - uses: actions/cache@v3
+      - uses: actions/cache/restore@v3
+        id: restore-cache
         with:
           path: |
             ~/.cargo/bin/
@@ -106,6 +107,12 @@ jobs:
         run: |
           cargo build --package nargo_cli --release --target ${{ matrix.target }} --no-default-features --features plonk_bn254_wasm
 
+      - uses: actions/cache/save@v3
+        if: ${{ github.event_name != 'merge_group' }} # Don't create cache entries for the merge queue.
+        with:
+          path: ${{ steps.restore-cache.inputs.path }}
+          key: ${{ steps.restore-cache.outputs.cache-primary-key }}
+
       - name: Package artifacts
         run: |
           mkdir dist
@@ -161,7 +168,8 @@ jobs:
         with:
           ref: ${{ inputs.tag || env.GITHUB_REF }}
 
-      - uses: actions/cache@v3
+      - uses: actions/cache/restore@v3
+        id: restore-cache
         with:
           path: |
             ~/.cargo/bin/
@@ -189,6 +197,12 @@ jobs:
           cargo install cross --force --git https://github.com/cross-rs/cross
           cross build --package nargo_cli --release --target=${{ matrix.target }} --no-default-features --features plonk_bn254_wasm
 
+      - uses: actions/cache/save@v3
+        if: ${{ github.event_name != 'merge_group' }} # Don't create cache entries for the merge queue.
+        with:
+          path: ${{ steps.restore-cache.inputs.path }}
+          key: ${{ steps.restore-cache.outputs.cache-primary-key }}
+
       - name: Package artifacts
         run: |
           mkdir dist
@@ -237,7 +251,8 @@ jobs:
         with:
           ref: ${{ inputs.tag || env.GITHUB_REF }}
 
-      - uses: actions/cache@v3
+      - uses: actions/cache/restore@v3
+        id: restore-cache
         with:
           path: |
             ~/.cargo/bin/
@@ -264,6 +279,12 @@ jobs:
         run: |
           cargo build --package nargo_cli --release --target ${{ matrix.target }} --no-default-features --features plonk_bn254_wasm
 
+      - uses: actions/cache/save@v3
+        if: ${{ github.event_name != 'merge_group' }} # Don't create cache entries for the merge queue.
+        with:
+          path: ${{ steps.restore-cache.inputs.path }}
+          key: ${{ steps.restore-cache.outputs.cache-primary-key }}
+
       - name: Package artifacts
         run: |
           mkdir dist

.github/workflows/test.yml

@@ -37,15 +37,15 @@ jobs:
           name: barretenberg
 
       - name: Restore nix store cache
-        id: nix-store-cache
-        uses: actions/cache@v3
+        uses: actions/cache/restore@v3
+        id: restore-cache
         with:
           path: /tmp/nix-cache
           key: ${{ runner.os }}-flake-${{ hashFiles('*.lock') }}
 
       # Based on https://github.com/marigold-dev/deku/blob/b5016f0cf4bf6ac48db9111b70dd7fb49b969dfd/.github/workflows/build.yml#L26
       - name: Copy cache into nix store
-        if: steps.nix-store-cache.outputs.cache-hit == 'true'
+        if: steps.restore-cache.outputs.cache-hit == 'true'
         # We don't check the signature because we're the one that created the cache
         run: |
           for narinfo in /tmp/nix-cache/*.narinfo; do
@@ -61,3 +61,10 @@ jobs:
         if: steps.nix-store-cache.outputs.cache-hit != 'true'
         run: |
           nix copy --to "file:///tmp/nix-cache?compression=zstd&parallel-compression=true" .#native-cargo-artifacts
+
+      - uses: actions/cache/save@v3
+        # Write a cache entry even if the tests fail but don't create any for the merge queue.
+        if: ${{ always() && github.event_name != 'merge_group' }}
+        with:
+          path: ${{ steps.restore-cache.inputs.path }}
+          key: ${{ steps.restore-cache.outputs.cache-primary-key }}

.github/workflows/wasm.yml

@@ -54,7 +54,8 @@ jobs:
       - name: Checkout Noir repo
         uses: actions/checkout@v3
 
-      - uses: actions/cache@v3
+      - uses: actions/cache/restore@v3
+        id: restore-cache
         with:
           path: |
             ~/.cargo/bin/
@@ -79,6 +80,12 @@ jobs:
         run: |
           cargo build --package nargo_cli --release --no-default-features --features plonk_bn254_wasm
 
+      - uses: actions/cache/save@v3
+        if: ${{ github.event_name != 'merge_group' }} # Don't create cache entries for the merge queue.
+        with:
+          path: ${{ steps.restore-cache.inputs.path }}
+          key: ${{ steps.restore-cache.outputs.cache-primary-key }}
+
       - name: Package artifacts
         run: |
           mkdir dist