build: Add CI and Task for formatting R and Rust code

.github/workflows/format.yml

@@ -0,0 +1,30 @@
+name: format
+
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref }}
+  cancel-in-progress: true
+
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Rust
+        run: rustup component add rustfmt
+
+      - name: Install `air`
+        run: curl -LsSf https://github.com/posit-dev/air/releases/latest/download/air-installer.sh | sh
+
+      - name: Check formatting in R
+        run: air format . --check
+
+      - name: Check formatting in Rust
+        run: cargo fmt --all --check --manifest-path src/rust/Cargo.toml

Taskfile.yml

@@ -158,3 +158,20 @@ tasks:
     desc: Accept all test snapshots. (Shortcut to accept snapshots after running tests)
     cmds:
       - Rscript -e 'testthat::snapshot_accept()'
+
+  install-air:
+    desc: Install Air to format R code.
+    cmds:
+      - curl -LsSf https://github.com/posit-dev/air/releases/latest/download/air-installer.sh | sh
+
+  fmt:
+    desc: Format all R and Rust code.
+    sources:
+      - "{{.R_SOURCE}}"
+      - "{{.RUST_SOURCE}}"
+      - tests/**/*
+    deps:
+      - install-air
+    cmds:
+      - air format .
+      - cargo fmt --all --manifest-path src/rust/Cargo.toml

air.toml

@@ -0,0 +1,7 @@
+[format]
+line-width = 80
+indent-width = 2
+indent-style = "space"
+line-ending = "auto"
+persistent-line-breaks = true
+exclude = ["R/000-wrappers.R"]