Improvements to CI and the Justfile. (#119)

In CI, I have added workflows and jobs to:

* run `cargo machete`
* ensure the lockfile doesn't change
* share a Rust cache

I've also aligned the justfile with CI, and fixed the `just dev` target.

.github/workflows/build.yaml

@@ -18,7 +18,27 @@ jobs:
           rustup show
 
       - uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: "build" # share the cache across jobs
 
       - name: build
         run: |
           cargo build --release --all-targets --all-features
+
+      # Sadly, `cargo build --locked` isn't enough to check that the lockfile
+      # is up to date, as it will happily run even if there are extra entries in
+      # there.
+      #
+      # It does, however, make sure that the file is not updated, which is quite
+      # unhelpful.
+      - name: ensure lockfile hasn't changed
+        run: |
+          if [[ -n "$(git status --porcelain Cargo.lock)" ]]; then
+            echo 'The Cargo.lock file was changed!'
+            git diff Cargo.lock
+            exit 1
+          fi
+
+      - name: clippy
+        run: |
+          cargo clippy --release --all-targets --all-features

.github/workflows/format.yaml

@@ -0,0 +1,22 @@
+name: format
+
+on:
+  push:
+
+jobs:
+  cargo-fmt:
+    name: check formatting with cargo fmt
+    runs-on: ubuntu-latest
+    env:
+      CARGO_NET_GIT_FETCH_WITH_CLI: "true"
+      RUSTFLAGS: "-D warnings" # fail on warnings
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: install tools
+        run: |
+          rustup show
+
+      - name: check formatting
+        run: |
+          cargo fmt --all --check

.github/workflows/machete.yaml

@@ -0,0 +1,28 @@
+name: find unused dependencies
+
+on:
+  push:
+
+jobs:
+  cargo-machete:
+    name: find unused dependencies with cargo machete
+    runs-on: ubuntu-latest
+    env:
+      CARGO_NET_GIT_FETCH_WITH_CLI: "true"
+      RUSTFLAGS: "-D warnings" # fail on warnings
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: install tools
+        run: |
+          rustup show
+          cargo install cargo-machete
+
+      - uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: "build" # share the cache across jobs
+          save-if: false
+
+      - name: find unused dependencies
+        run: |
+          cargo machete --with-metadata

.github/workflows/test.yaml

@@ -18,6 +18,9 @@ jobs:
           rustup show
 
       - uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: "build" # share the cache across jobs
+          save-if: false
 
       - name: run tests
-        run: cargo test
+        run: cargo test --release --all-targets --all-features

.gitignore

@@ -3,3 +3,6 @@
 
 # direnv
 /.direnv
+
+# testing
+/tmp/empty