Cache Cargo registry

Cache standalone index and cache to speed up the CI.

https: //doc.rust-lang.org/cargo/guide/cargo-home.html#caching-the-cargo-home-in-ci

Signed-off-by: Mickaël Salaün <mic@digikod.net>

Author: l0kod

.github/workflows/ci.yml

@@ -74,15 +74,51 @@ jobs:
     - name: Check JSON scoped
       run: ./schema/check.sh examples/mini-scoped.json
 
+  cache_cargo_index:
+    runs-on: ubuntu-24.04
+    steps:
+
+    - uses: actions/checkout@v4
+
+    - name: Cache Cargo registry index
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/.cargo/registry/index
+        key: cargo-registry-index-${{ github.sha }}
+        restore-keys: |
+          cargo-registry-index-
+
+    - name: Update Cargo registry
+      run: cargo update
+
   ubuntu_24_rust_msrv:
     runs-on: ubuntu-24.04
-    needs: commit_list
+    needs: commit_list cache_cargo_index
     strategy:
       fail-fast: false
       matrix:
         commit: ${{ fromJSON(needs.commit_list.outputs.commits) }}
     steps:
 
+    - name: Restore Cargo registry index cache
+      uses: actions/cache/restore@v4
+      with:
+        path: |
+          ~/.cargo/registry/index
+        key: cargo-registry-index-${{ github.sha }}
+        restore-keys: |
+          cargo-registry-index-
+
+    - name: Cache Cargo registry MSRV cache
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/.cargo/registry/cache
+        key: cargo-registry-cache-msrv-${{ github.sha }}
+        restore-keys: |
+          cargo-registry-cache-msrv-
+
     - name: Install cargo-c
       run: sudo apt install cargo-c
 
@@ -117,13 +153,31 @@ jobs:
 
   ubuntu_24_rust_stable:
     runs-on: ubuntu-24.04
-    needs: commit_list
+    needs: commit_list cache_cargo_index
     strategy:
       fail-fast: false
       matrix:
         commit: ${{ fromJSON(needs.commit_list.outputs.commits) }}
     steps:
 
+    - name: Restore Cargo registry index cache
+      uses: actions/cache/restore@v4
+      with:
+        path: |
+          ~/.cargo/registry/index
+        key: cargo-registry-index-${{ github.sha }}
+        restore-keys: |
+          cargo-registry-index-
+
+    - name: Cache Cargo registry stable cache
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/.cargo/registry/cache
+        key: cargo-registry-cache-stable-${{ github.sha }}
+        restore-keys: |
+          cargo-registry-cache-stable-
+
     - name: Install cargo-c
       run: sudo apt install cargo-c