Add MSRV verification jobs to the CI. (#523)

* Update dependencies.

* Add `Cargo.lock`.

* Add MSRV verification jobs to the CI.

* Add MSRV acronym for easier searching.

* Add `--locked` to all cargo commands that support it.

* Add a brief rationale for MSRV job design.

* Adjust MSRV sync notice in `Cargo.toml`.

.github/workflows/ci.yml

@@ -4,6 +4,14 @@ env:
   # come automatically. If the version specified here is no longer the latest stable version,
   # then please feel free to submit a PR that adjusts it along with the potential clippy fixes.
   RUST_STABLE_VER: "1.76" # In quotes because otherwise (e.g.) 1.70 would be interpreted as 1.7
+  # The purpose of checking with the minimum supported Rust toolchain is to detect its staleness.
+  # If the compilation fails, then the version specified here needs to be bumped up to reality.
+  # Be sure to also update the rust-version property in the workspace Cargo.toml file,
+  # plus all the README.md files of the affected packages.
+  RUST_MIN_VER: "1.75"
+  # List of packages that will be checked with the minimum supported Rust version.
+  # This should be limited to packages that are intended for publishing.
+  RUST_MIN_VER_PKGS: "-p vello -p vello_encoding -p vello_shaders"
 
 
 # Rationale
@@ -31,6 +39,9 @@ env:
 # This explicit dependency can be switched back to macos-latest once it points to macos-14,
 # which is expected to happen sometime in Q2 FY24 (April – June 2024).
 # https://github.blog/changelog/2024-01-30-github-actions-macos-14-sonoma-is-now-available/
+#
+# The MSRV jobs run only cargo check because different clippy versions can disagree on goals and
+# running tests introduces dev dependencies which may require a higher MSRV than the bare package.
 
 name: CI
 
@@ -90,10 +101,10 @@ jobs:
         run: sudo apt-get update; sudo apt-get install --no-install-recommends libasound2-dev libudev-dev
 
       - name: cargo clippy
-        run: cargo hack clippy --workspace --each-feature --optional-deps -- -D warnings
+        run: cargo hack clippy --workspace --locked --each-feature --optional-deps -- -D warnings
 
       - name: cargo clippy (auxiliary)
-        run: cargo hack clippy --workspace --each-feature --optional-deps --tests --benches --examples -- -D warnings
+        run: cargo hack clippy --workspace --locked --each-feature --optional-deps --tests --benches --examples -- -D warnings
 
   clippy-stable-wasm:
     name: cargo clippy (wasm32)
@@ -117,10 +128,10 @@ jobs:
           tool: cargo-hack
 
       - name: cargo clippy
-        run: cargo hack clippy --workspace --target wasm32-unknown-unknown --each-feature --optional-deps -- -D warnings
+        run: cargo hack clippy --workspace --locked --target wasm32-unknown-unknown --each-feature --optional-deps -- -D warnings
 
       - name: cargo clippy (auxiliary)
-        run: cargo hack clippy --workspace --target wasm32-unknown-unknown --each-feature --optional-deps --tests --benches --examples -- -D warnings
+        run: cargo hack clippy --workspace --locked --target wasm32-unknown-unknown --each-feature --optional-deps --tests --benches --examples -- -D warnings
 
   test-stable:
     name: cargo test
@@ -164,7 +175,7 @@ jobs:
           sudo apt install -y xvfb libegl1-mesa libgl1-mesa-dri libxcb-xfixes0-dev mesa-vulkan-drivers
 
       - name: cargo test
-        run: cargo test --workspace --all-features
+        run: cargo test --workspace --locked --all-features
         env:
           VELLO_CI_GPU_SUPPORT: ${{ matrix.gpu }}
 
@@ -186,7 +197,7 @@ jobs:
 
       # TODO: Find a way to make tests work. Until then the tests are merely compiled.
       - name: cargo test compile
-        run: cargo test --workspace --target wasm32-unknown-unknown --all-features --no-run
+        run: cargo test --workspace --locked --target wasm32-unknown-unknown --all-features --no-run
 
   check-stable-android:
     name: cargo check (aarch64-android)
@@ -212,6 +223,58 @@ jobs:
           # This is a bit of a hack, but cargo apk doesn't seem to allow customising this
           RUSTFLAGS: '-D warnings'
 
+  check-msrv:
+    name: cargo check (msrv)
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [windows-latest, macos-14, ubuntu-latest]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: restore cache
+        uses: Swatinem/rust-cache@v2
+
+      - name: install msrv toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ env.RUST_MIN_VER }}
+
+      - name: install cargo-hack
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-hack
+
+      - name: install native dependencies
+        if: matrix.os == 'ubuntu-latest'
+        run: sudo apt-get update; sudo apt-get install --no-install-recommends libasound2-dev libudev-dev
+
+      - name: cargo check
+        run: cargo hack check ${{ env.RUST_MIN_VER_PKGS }} --locked --each-feature --optional-deps
+
+  check-msrv-wasm:
+    name: cargo check (msrv) (wasm32)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: restore cache
+        uses: Swatinem/rust-cache@v2
+
+      - name: install msrv toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ env.RUST_MIN_VER }}
+          targets: wasm32-unknown-unknown
+
+      - name: install cargo-hack
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-hack
+
+      - name: cargo check
+        run: cargo hack check ${{ env.RUST_MIN_VER_PKGS }} --locked --target wasm32-unknown-unknown --each-feature --optional-deps
+
   doc:
     name: cargo doc
     # NOTE: We don't have any platform specific docs in this workspace, so we only run on Ubuntu.
@@ -228,4 +291,4 @@ jobs:
 
       # We test documentation using nightly to match docs.rs. This prevents potential breakages
       - name: cargo doc
-        run: cargo doc --workspace --all-features --no-deps --document-private-items -Zunstable-options -Zrustdoc-scrape-examples
+        run: cargo doc --workspace --locked --all-features --no-deps --document-private-items -Zunstable-options -Zrustdoc-scrape-examples

.gitignore

@@ -1,5 +1,4 @@
 /target
-Cargo.lock
 /trace.json
 .DS_Store