Setup pre-commit (#28)

.editorconfig

@@ -0,0 +1,20 @@
+# Check http://editorconfig.org for more information
+# This is the main config file for this project:
+root = true
+
+[*]
+charset = utf-8
+trim_trailing_whitespace = true
+end_of_line = lf
+indent_style = space
+insert_final_newline = true
+indent_size = 2
+
+[*.{rs,py,pyi}]
+indent_size = 4
+
+[*.md]
+max_line_length = 100
+
+[*.toml]
+indent_size = 4

.markdownlint.yaml

@@ -0,0 +1,31 @@
+# default to true for all rules
+default: true
+
+# MD007/unordered-list-indent
+MD007:
+  indent: 4
+
+# MD033/no-inline-html
+MD033: false
+
+# MD041/first-line-h1
+MD041: false
+
+# MD013/line-length
+MD013: false
+
+# MD014/commands-show-output
+MD014: false
+
+# MD024/no-duplicate-heading
+MD024:
+  # Allow when nested under different parents e.g. CHANGELOG.md
+  siblings_only: true
+
+# MD046/code-block-style
+#
+# Ignore this because it conflicts with the code block style used in content
+# tabs of mkdocs-material which is to add a blank line after the content title.
+#
+# Ref: https://github.com/astral-sh/ruff/pull/15011#issuecomment-2544790854
+MD046: false

.pre-commit-config.yaml

@@ -0,0 +1,75 @@
+fail_fast: false
+
+exclude: |
+  (?x)^(
+    .github/workflows/release.yml|
+    ruff/.*|
+  )$
+
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: check-merge-conflict
+
+  - repo: https://github.com/abravalheri/validate-pyproject
+    rev: v0.24.1
+    hooks:
+      - id: validate-pyproject
+
+  - repo: https://github.com/executablebooks/mdformat
+    rev: 0.7.22
+    hooks:
+      - id: mdformat
+        additional_dependencies:
+          - mdformat-mkdocs==4.0.0
+          - mdformat-footnote==0.1.1
+
+  - repo: https://github.com/igorshubovych/markdownlint-cli
+    rev: v0.44.0
+    hooks:
+      - id: markdownlint-fix
+
+  - repo: https://github.com/crate-ci/typos
+    rev: v1.32.0
+    hooks:
+      - id: typos
+
+  # Prettier
+  - repo: https://github.com/rbubley/mirrors-prettier
+    rev: v3.5.3
+    hooks:
+      - id: prettier
+        types: [yaml]
+
+  # zizmor detects security vulnerabilities in GitHub Actions workflows.
+  # Additional configuration for the tool is found in `.github/zizmor.yml`
+  - repo: https://github.com/woodruffw/zizmor-pre-commit
+    rev: v1.6.0
+    hooks:
+      - id: zizmor
+
+  - repo: https://github.com/python-jsonschema/check-jsonschema
+    rev: 0.33.0
+    hooks:
+      - id: check-github-workflows
+
+  # `actionlint` hook, for verifying correct syntax in GitHub Actions workflows.
+  # Some additional configuration for `actionlint` can be found in `.github/actionlint.yaml`.
+  - repo: https://github.com/rhysd/actionlint
+    rev: v1.7.7
+    hooks:
+      - id: actionlint
+        stages:
+          # This hook is disabled by default, since it's quite slow.
+          # To run all hooks *including* this hook, use `uvx pre-commit run -a --hook-stage=manual`.
+          # To run *just* this hook, use `uvx pre-commit run -a actionlint --hook-stage=manual`.
+          - manual
+        args:
+          - "-ignore=SC2129" # ignorable stylistic lint from shellcheck
+          - "-ignore=SC2016" # another shellcheck lint: seems to have false positives?
+        additional_dependencies:
+          # actionlint has a shellcheck integration which extracts shell scripts in `run:` steps from GitHub Actions
+          # and checks these with shellcheck. This is arguably its most useful feature,
+          # but the integration only works if shellcheck is installed
+          - "github.com/wasilibs/go-shellcheck/cmd/shellcheck@v0.10.0"

CONTRIBUTING.md

@@ -17,21 +17,34 @@ The ty repository only includes code relevant to distributing the ty project.
 
 Clone the repository:
 
-```
+```bash
 git clone https://github.com/astral-sh/ty.git
 ```
 
 Then, ensure the submodule is initialized:
 
-```
+```bash
 git submodule update --init --recursive
 ```
 
+### Prerequisites
+
+You'll need [uv](https://docs.astral.sh/uv/getting-started/installation/) (or `pipx` and `pip`) to
+run Python utility commands.
+
+You can optionally install pre-commit hooks to automatically run the validation checks
+when making a commit:
+
+```shell
+uv tool install pre-commit
+pre-commit install
+```
+
 ## Building the Python package
 
 The Python package can be built with any Python build frontend (Maturin is used as a backend), e.g.:
 
-```
+```bash
 uv build
 ```
 
@@ -39,19 +52,19 @@ uv build
 
 To update the Ruff submodule to the latest commit:
 
-```
+```bash
 git -C ruff pull origin main
 ```
 
 Or, to update the Ruff submodule to a specific commit:
 
-```
+```bash
 git -C ruff checkout <commit>
 ```
 
 To commit the changes:
 
-```
+```bash
 commit=$(git -C ruff rev-parse --short HEAD)
 git switch -c "sync/ruff-${commit}"
 git add ruff