CI: optimize build performance

- Add toolchain-specific and shared cache keys for better cache utilization
- Enable incremental compilation and optimize RUSTFLAGS for faster builds
- Add manual cache refresh capability via workflow dispatch
- Include optional nextest installation for faster test execution
- Improve cache efficiency with conditional saving on main branches

Mostly inspired from o1-labs/proof-systems

Author: dannywillems

.github/actions/setup-build-deps/action.yml

@@ -5,6 +5,10 @@ inputs:
     description: 'Include SQLite3 in the installation'
     required: false
     default: 'false'
+  install-nextest:
+    description: 'Install cargo-nextest for faster test execution'
+    required: false
+    default: 'false'
 runs:
   using: 'composite'
   steps:
@@ -23,4 +27,10 @@ runs:
       if: runner.os == 'macOS'
       shell: bash
       run: |
-        brew install protobuf
+        brew install protobuf
+
+    - name: Install cargo-nextest
+      if: inputs.install-nextest == 'true'
+      uses: taiki-e/install-action@v2
+      with:
+        tool: nextest

.github/actions/setup-rust/action.yml

@@ -30,4 +30,6 @@ runs:
       if: inputs.enable-cache == 'true'
       uses: Swatinem/rust-cache@v2
       with:
-        prefix-key: ${{ inputs.cache-prefix }}
+        prefix-key: ${{ inputs.cache-prefix }}-${{ inputs.toolchain }}
+        shared-key: shared-${{ inputs.toolchain }}
+        save-if: ${{ github.ref == 'refs/heads/develop' || github.ref == 'refs/heads/main' }}

.github/workflows/ci.yaml

@@ -5,17 +5,38 @@ on:
   pull_request:
     paths-ignore: [ "frontend" ]
   workflow_dispatch:
+    inputs:
+      refresh_cache:
+        description: 'Refresh cargo cache'
+        required: false
+        type: boolean
+        default: false
 
 env:
   CARGO_TERM_COLOR: always
   RUST_BACKTRACE: full
   OPENMINA_PANIC_ON_BUG: true
+  CARGO_INCREMENTAL: 1
+  RUSTFLAGS: "-C overflow-checks=off -C debug-assertions=off"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true
 
 jobs:
+  refresh-cache:
+    if: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.refresh_cache == 'true' }}
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v5
+      - name: Setup Rust
+        uses: ./.github/actions/setup-rust
+        with:
+          toolchain: 1.84
+          enable-cache: false
+      - name: Clean cargo cache
+        run: cargo clean
+
   ledger-tests:
     timeout-minutes: 20
     runs-on: ubuntu-24.04