ci: check build with MSRV

Author: bavshin-f5

.github/workflows/ci.yaml

@@ -8,9 +8,29 @@ env:
   RUSTDOCFLAGS: '-Dwarnings'
 
 jobs:
+  rust-version:
+    name: Minimal supported Rust version
+    outputs:
+      version: ${{ steps.read_version.outputs.msrv }}
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - id: read_version
+        run: |
+          awk -F '=' \
+            '/^rust-version[[:space:]]*=/ { gsub(/([" ]|#.*)/,"",$2); print ("msrv=" $2) }' \
+            Cargo.toml \
+          | tee -a "$GITHUB_OUTPUT"
+
   test-linux:
     name: Test (Linux)
+    needs: rust-version
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust-version:
+          - ${{ needs.rust-version.outputs.version }}
+          - stable
     steps:
       - name: checkout source
         uses: actions/checkout@v4
@@ -24,8 +44,8 @@ jobs:
             ~/.cargo/registry/cache/
             ~/.cargo/git/db/
             target/
-          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: ${{ runner.os }}-cargo-
+          key: ${{ runner.os }}-cargo-${{ matrix.rust-version}}-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ${{ runner.os }}-cargo-${{ matrix.rust-version }}-
       - name: set up nginx deps cache
         uses: actions/cache@v4
         continue-on-error: false
@@ -38,24 +58,29 @@ jobs:
             .cache/*.tar.sig
           key:  ${{ runner.os }}-deps-${{ hashFiles('**/nginx-sys/build.rs') }}
           restore-keys: ${{ runner.os }}-deps-
-      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: dtolnay/rust-toolchain@master
         with:
           components: rustfmt, clippy
+          toolchain: ${{ matrix.rust-version }}
 
       - name: build
         id: build
         run: cargo build --workspace --all-targets --all-features
 
       - name: run clippy
-        if: ${{ !cancelled() && steps.build.outcome == 'success' }}  # always run if build succeeds
+        # always run if build succeeds
+        if: ${{ !cancelled() && steps.build.outcome == 'success' }}
         run: cargo clippy --workspace --all-targets --all-features -- -Dwarnings
 
       - name: run tests
-        if: ${{ !cancelled() && steps.build.outcome == 'success' }}  # always run if build succeeds
+        # always run if build succeeds
+        if: ${{ !cancelled() && steps.build.outcome == 'success' }}
         run: cargo test --workspace --all-features
 
       - name: rustdoc
-        if: ${{ !cancelled() && steps.build.outcome == 'success' }}  # always run if build succeeds
+        # always run if build succeeds
+        if: ${{ !cancelled() && steps.build.outcome == 'success' }}
         run: cargo doc --no-deps
 
   examples-linux: