chore: migrate to justfile, and make CI use it

.github/workflows/ci.yml

@@ -0,0 +1,64 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  release:
+    types: [ published ]
+  workflow_dispatch:
+
+defaults:
+  run:
+    shell: bash
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  test:
+    name: Test
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ ubuntu-latest, macos-15 ]
+    steps:
+      - uses: actions/checkout@v4
+      - if: github.event_name != 'release' && github.event_name != 'workflow_dispatch'
+        uses: Swatinem/rust-cache@v2
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: taiki-e/install-action@v2
+        with: { tool: just }
+      - run: just ci-test
+
+  test-msrv:
+    name: Test MSRV
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ ubuntu-latest, macos-15 ]
+    steps:
+      - uses: actions/checkout@v4
+      - if: github.event_name != 'release' && github.event_name != 'workflow_dispatch'
+        uses: Swatinem/rust-cache@v2
+      - uses: taiki-e/install-action@v2
+        with: { tool: just }
+      - name: Read MSRV
+        id: msrv
+        run: echo "value=$(just get-msrv)" >> $GITHUB_OUTPUT
+      - name: Install MSRV Rust ${{ steps.msrv.outputs.value }}
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: ${{ steps.msrv.outputs.value }}
+      - run: just ci_mode=0 ci-test-msrv  # Ignore warnings in MSRV
+
+  # This job checks if any of the previous jobs failed or were canceled.
+  # This approach also allows some jobs to be skipped if they are not needed.
+  ci-passed:
+    needs: [ test, test-msrv ]
+    if: always()
+    runs-on: ubuntu-latest
+    steps:
+      - if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+        run: exit 1

README.md

@@ -59,16 +59,17 @@ The library is completely safe.
 
 There are no `unsafe` in this library and in most of its dependencies (excluding `bytemuck`).
 
-## Developer documents
-
-For notes on the backporting process of HarfBuzz code, see [docs/backporting.md](docs/backporting.md).
-
-For notes on generating state machine using `ragel`, see [docs/ragel.md](docs/ragel.md).
-
-The following HarfBuzz _studies_ are relevant to HarfRust development:
-
-- 2025 - [Introducing HarfRust][2]
-- 2025 – [Caching][1]
+## Development
+
+* This project is easier to develop with [just](https://github.com/casey/just#readme), a modern alternative to `make`.
+  Install it with `cargo install just`.
+  * To get a list of available commands, run `just`.
+  * To run tests, use `just test`.
+* For notes on the backporting process of HarfBuzz code, see [docs/backporting.md](docs/backporting.md).
+* For notes on generating state machine using `ragel`, see [docs/ragel.md](docs/ragel.md).
+* The following HarfBuzz _studies_ are relevant to HarfRust development:
+  - 2025 - [Introducing HarfRust][2]
+  - 2025 – [Caching][1]
 
 ## License
 

justfile

@@ -0,0 +1,150 @@
+#!/usr/bin/env just --justfile
+
+main_crate := 'harfrust'
+features_flag := '--all-features'
+
+# if running in CI, treat warnings as errors by setting RUSTFLAGS and RUSTDOCFLAGS to '-D warnings' unless they are already set
+# Use `CI=true just ci-test` to run the same tests as in GitHub CI.
+# Use `just env-info` to see the current values of RUSTFLAGS and RUSTDOCFLAGS
+ci_mode := if env('CI', '') != '' {'1'} else {''}
+export RUSTFLAGS := env('RUSTFLAGS', if ci_mode == '1' {'-D warnings'} else {''})
+export RUSTDOCFLAGS := env('RUSTDOCFLAGS', if ci_mode == '1' {'-D warnings'} else {''})
+export RUST_BACKTRACE := env('RUST_BACKTRACE', if ci_mode == '1' {'1'} else {''})
+
+@_default:
+    {{just_executable()}} --list
+
+# Build the project
+build: build-lib build-lib-no-std
+    cargo build --workspace --all-targets {{features_flag}}
+
+# Build just the core lib
+build-lib:
+    cargo build --lib --package {{main_crate}} {{features_flag}}
+
+# Build just the core lib with no_std
+build-lib-no-std:
+    cargo build --lib --package {{main_crate}} --no-default-features
+
+# Quick compile without building a binary
+check:
+    cargo check --workspace --all-targets {{features_flag}}
+    cargo check --lib --package {{main_crate}} {{features_flag}}
+    cargo check --lib --package {{main_crate}} --no-default-features
+
+# Generate code coverage report to upload to codecov.io
+ci-coverage: env-info && \
+            (coverage '--codecov --output-path target/llvm-cov/codecov.info')
+    # ATTENTION: the full file path above is used in the CI workflow
+    mkdir -p target/llvm-cov
+
+# Run all tests as expected by CI
+ci-test: env-info test-fmt build test test-doc clippy && assert-git-is-clean
+
+# Run minimal subset of tests to ensure compatibility with MSRV
+ci-test-msrv: env-info build-lib build-lib-no-std
+
+# Clean all build artifacts
+clean:
+    cargo clean
+    rm -f Cargo.lock
+
+# Run cargo clippy to lint the code
+clippy *args:
+    cargo clippy --workspace --all-targets {{features_flag}} {{args}}
+
+# Generate code coverage report. Will install `cargo llvm-cov` if missing.
+coverage *args='--no-clean --open':  (cargo-install 'cargo-llvm-cov')
+    cargo llvm-cov --workspace --all-targets {{features_flag}} --include-build-script {{args}}
+
+# Build and open code documentation
+docs *args='--open':
+    DOCS_RS=1 cargo doc --no-deps {{args}} --workspace {{features_flag}}
+
+# Print environment info
+env-info:
+    @echo "Running {{if ci_mode == '1' {'in CI mode'} else {'in dev mode'} }} on {{os()}} / {{arch()}}"
+    {{just_executable()}} --version
+    rustc --version
+    cargo --version
+    rustup --version
+    @echo "RUSTFLAGS='$RUSTFLAGS'"
+    @echo "RUSTDOCFLAGS='$RUSTDOCFLAGS'"
+    @echo "RUST_BACKTRACE='$RUST_BACKTRACE'"
+
+# Reformat all code `cargo fmt`.
+fmt:
+    cargo fmt --all
+
+# Get any package's field from the metadata
+get-crate-field field package=main_crate:  (assert-cmd 'jq')
+    cargo metadata --format-version 1 | jq -e -r '.packages | map(select(.name == "{{package}}")) | first | .{{field}} | select(. != null)'
+
+# Get the minimum supported Rust version (MSRV) for the crate
+get-msrv package=main_crate:  (get-crate-field 'rust_version' package)
+
+# Find the minimum supported Rust version (MSRV) using cargo-msrv extension, and update Cargo.toml
+msrv:  (cargo-install 'cargo-msrv')
+    cargo msrv find --write-msrv --ignore-lockfile {{features_flag}}
+
+release *args='':  (cargo-install 'release-plz')
+    release-plz {{args}}
+
+# Check semver compatibility with prior published version. Install it with `cargo install cargo-semver-checks`
+semver *args:  (cargo-install 'cargo-semver-checks')
+    cargo semver-checks {{features_flag}} {{args}}
+
+# Run all unit and integration tests
+test:
+    cargo test --workspace --all-targets {{features_flag}}
+    cargo test --workspace --doc {{features_flag}}
+
+# Test documentation generation
+test-doc:  (docs '')
+
+# Test code formatting
+test-fmt:
+    cargo fmt --all -- --check
+
+# Find unused dependencies. Install it with `cargo install cargo-udeps`
+udeps:  (cargo-install 'cargo-udeps')
+    cargo +nightly udeps --workspace --all-targets {{features_flag}}
+
+# Update all dependencies, including breaking changes. Requires nightly toolchain (install with `rustup install nightly`)
+update:
+    cargo +nightly -Z unstable-options update --breaking
+    cargo update
+
+# Ensure that a certain command is available
+[private]
+assert-cmd command:
+    @if ! type {{command}} > /dev/null; then \
+        echo "Command '{{command}}' could not be found. Please make sure it has been installed on your computer." ;\
+        exit 1 ;\
+    fi
+
+# Make sure the git repo has no uncommitted changes
+[private]
+assert-git-is-clean:
+    @if [ -n "$(git status --untracked-files --porcelain)" ]; then \
+      >&2 echo "ERROR: git repo is no longer clean. Make sure compilation and tests artifacts are in the .gitignore, and no repo files are modified." ;\
+      >&2 echo "######### git status ##########" ;\
+      git status ;\
+      git --no-pager diff ;\
+      exit 1 ;\
+    fi
+
+# Check if a certain Cargo command is installed, and install it if needed
+[private]
+cargo-install $COMMAND $INSTALL_CMD='' *args='':
+    #!/usr/bin/env bash
+    set -euo pipefail
+    if ! command -v $COMMAND > /dev/null; then
+        if ! command -v cargo-binstall > /dev/null; then
+            echo "$COMMAND could not be found. Installing it with    cargo install ${INSTALL_CMD:-$COMMAND} --locked {{args}}"
+            cargo install ${INSTALL_CMD:-$COMMAND} --locked {{args}}
+        else
+            echo "$COMMAND could not be found. Installing it with    cargo binstall ${INSTALL_CMD:-$COMMAND} --locked {{args}}"
+            cargo binstall ${INSTALL_CMD:-$COMMAND} --locked {{args}}
+        fi
+    fi