Update Actions CI with improved workflow

.github/workflows/ci.yml

@@ -3,40 +3,6 @@ name: CI checks
 on: [push, pull_request]
 
 jobs:
-  lint:
-    name: Lint
-    runs-on: ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v1
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: 1.44.1
-          override: true
-
-      # cargo fmt does not build the code, and running it in a fresh clone of
-      # the codebase will fail because the protobuf code has not been generated.
-      - name: cargo build
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --all
-
-      # Ensure all code has been formatted with rustfmt
-      - run: rustup component add rustfmt
-      - name: Check formatting
-        uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check --color always
-
-      # Build benchmarks to prevent bitrot
-      - name: Build benchmarks
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --all --benches
-
   test:
     name: Test on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
@@ -45,7 +11,7 @@ jobs:
         os: [ubuntu-latest, windows-latest, macOS-latest]
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: 1.44.1
@@ -65,15 +31,6 @@ jobs:
         working-directory: ./zcash_proofs
         run: cargo run --release --example download-params --features download-params
 
-      - name: cargo fetch
-        uses: actions-rs/cargo@v1
-        with:
-          command: fetch
-      - name: Build tests
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --all-features --verbose --release --all --tests
       - name: Run tests
         uses: actions-rs/cargo@v1
         with:
@@ -95,7 +52,7 @@ jobs:
           - wasm32-wasi
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: 1.44.1
@@ -109,13 +66,71 @@ jobs:
       - name: Build zcash_proofs for target
         working-directory: ./zcash_proofs
         run: cargo build --verbose --no-default-features --target ${{ matrix.target }}
+      - name: Build zcash_client_backend for target
+        working-directory: ./zcash_client_backend
+        run: cargo build --verbose --no-default-features --target ${{ matrix.target }}
+
+  bitrot:
+    name: Bitrot check
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: 1.44.1
+          override: true
+      # Build benchmarks to prevent bitrot
+      - name: Build benchmarks
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --all --benches
+
+  clippy:
+    name: Clippy (1.44.1)
+    timeout-minutes: 30
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: 1.44.1
+          components: clippy
+          override: true
+      - name: Run clippy
+        uses: actions-rs/clippy-check@v1
+        with:
+          name: Clippy (1.44.1)
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --all-features --all-targets -- -D warnings
+
+  clippy-nightly:
+    name: Clippy (nightly)
+    timeout-minutes: 30
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+          components: clippy
+          override: true
+      - name: Run Clippy (nightly)
+        uses: actions-rs/clippy-check@v1
+        continue-on-error: true
+        with:
+          name: Clippy (nightly)
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --all-features --all-targets
 
   codecov:
     name: Code coverage
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2
       # Use stable for this to ensure that cargo-tarpaulin can be built.
       - uses: actions-rs/toolchain@v1
         with:
@@ -147,16 +162,16 @@ jobs:
           command: tarpaulin
           args: --all-features --release --timeout 600 --out Xml
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v1.0.3
+        uses: codecov/codecov-action@v1
         with:
           token: ${{secrets.CODECOV_TOKEN}}
 
   doc-links:
-    name: Nightly lint
+    name: Intra-doc links
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: nightly
@@ -173,3 +188,30 @@ jobs:
         with:
           command: doc
           args: --all --document-private-items
+
+  fmt:
+    name: Rustfmt
+    timeout-minutes: 30
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: 1.44.1
+          override: true
+
+      # cargo fmt does not build the code, and running it in a fresh clone of
+      # the codebase will fail because the protobuf code has not been generated.
+      - name: cargo build
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --all
+
+      # Ensure all code has been formatted with rustfmt
+      - run: rustup component add rustfmt
+      - name: Check formatting
+        uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check