Run CI for the msrv and latest rust version (#37)

Author: leighmcculloch

.github/workflows/rust.yml

@@ -5,9 +5,6 @@ on:
     branches: [main]
   pull_request:
 
-env:
-  RUSTFLAGS: -D warnings
-
 jobs:
 
   complete:
@@ -35,12 +32,27 @@ jobs:
       run: rustup run nightly rust-analyzer analysis-stats . 2>&1 | (! grep ERROR)
 
   build-and-test:
+    strategy:
+      matrix:
+        rust: [msrv, latest]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
     - uses: stellar/actions/rust-cache@main
+    - name: Use the minimum supported Rust version
+      if: matrix.rust == 'msrv'
+      run: |
+        msrv="$(cargo metadata --format-version 1 --no-deps | jq -r '.packages | map(.rust_version) | map(values) | min')"
+        rustup override set $msrv
+        rustup component add clippy --toolchain $msrv
+    - name: Error on warnings and clippy checks
+      # Only error on warnings and checks for the msrv, because new versions of
+      # Rust will frequently add new warnings and checks.
+      if: matrix.rust == 'msrv'
+      run: echo RUSTFLAGS='-Dwarnings' >> $GITHUB_ENV
     - run: rustup update
-    - run: cargo build
+    - run: cargo version
+    - run: cargo clippy
     - run: cargo test
 
   docs:

Cargo.toml

@@ -8,7 +8,7 @@ readme = "README.md"
 license = "Apache-2.0"
 version = "0.0.5"
 edition = "2021"
-rust-version = "1.66"
+rust-version = "1.66.0"
 
 [lib]
 proc-macro = true