ci: Work around CI cache corruption on macOS (#249)

Author: Swatinem

.github/workflows/ci.yml

@@ -1,3 +1,9 @@
+# Notes on Caching:
+#
+# Caches are keyed by OS, rustc version, job and Cargo.toml hash.
+# We additionally cache the `Cargo.lock` file, as that is not being committed
+# directly to git.
+
 name: CI
 
 on:
@@ -11,6 +17,8 @@ jobs:
   lints:
     name: Lints
     runs-on: ubuntu-latest
+    env:
+      cache-name: lints
     steps:
       - name: Checkout sources
         uses: actions/checkout@v2
@@ -30,9 +38,10 @@ jobs:
             ~/.cargo/registry
             ~/.cargo/git
             target
-          key: ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-lints-${{ hashFiles('**/Cargo.toml') }}
+            Cargo.lock
+          key: ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}-${{ hashFiles('**/Cargo.toml') }}
           restore-keys: |
-            ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-lints-
+            ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}-
 
       - name: Run cargo fmt
         uses: actions-rs/cargo@v1
@@ -56,6 +65,8 @@ jobs:
     name: checkall using ${{ matrix.rust }} on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
 
+    env:
+      cache-name: check
     steps:
       - name: Checkout sources
         uses: actions/checkout@v2
@@ -68,15 +79,23 @@ jobs:
           toolchain: ${{ matrix.rust }}
           override: true
 
+      # workaround for: https://github.com/actions/cache/issues/403
+      - name: Install GNU tar (macOS)
+        if: runner.os == 'macOS'
+        run: |
+          brew install gnu-tar
+          echo "::add-path::/usr/local/opt/gnu-tar/libexec/gnubin"
+
       - uses: actions/cache@v2
         with:
           path: |
             ~/.cargo/registry
             ~/.cargo/git
             target
-          key: ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-check-${{ hashFiles('**/Cargo.toml') }}
+            Cargo.lock
+          key: ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}-${{ hashFiles('**/Cargo.toml') }}
           restore-keys: |
-            ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-check-
+            ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}-
 
       - run: make checkall
 
@@ -90,6 +109,8 @@ jobs:
     name: testall using ${{ matrix.rust }} on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
 
+    env:
+      cache-name: test
     steps:
       - name: Checkout sources
         uses: actions/checkout@v2
@@ -102,15 +123,23 @@ jobs:
           toolchain: ${{ matrix.rust }}
           override: true
 
+      # workaround for: https://github.com/actions/cache/issues/403
+      - name: Install GNU tar (macOS)
+        if: runner.os == 'macOS'
+        run: |
+          brew install gnu-tar
+          echo "::add-path::/usr/local/opt/gnu-tar/libexec/gnubin"
+
       - uses: actions/cache@v2
         with:
           path: |
             ~/.cargo/registry
             ~/.cargo/git
             target
-          key: ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-test-${{ hashFiles('**/Cargo.toml') }}
+            Cargo.lock
+          key: ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}-${{ hashFiles('**/Cargo.toml') }}
           restore-keys: |
-            ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-test-
+            ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}-
 
       - name: Run cargo test
         uses: actions-rs/cargo@v1
@@ -128,11 +157,14 @@ jobs:
     name: checkfast/testfast using ${{ matrix.rust }} on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
 
+    env:
+      cache-name: fast-MSRV
     steps:
       - name: Checkout sources
         uses: actions/checkout@v2
 
       - name: Install rust toolchain
+        id: toolchain
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -145,7 +177,10 @@ jobs:
             ~/.cargo/registry
             ~/.cargo/git
             target
-          key: ${{ runner.os }}-fast-msrv-${{ hashFiles('**/Cargo.toml') }}
+            Cargo.lock
+          key: ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}-${{ hashFiles('**/Cargo.toml') }}
+          restore-keys: |
+            ${{ runner.os }}-${{ steps.toolchain.outputs.rustc_hash }}-${{ env.cache-name }}
 
       - run: make checkfast