ci: Add Pre-commit hooks (#221)

https://pre-commit.com/

Author: holtskinner

.github/actions/spelling/excludes.txt

@@ -88,3 +88,4 @@
 CHANGELOG.md
 noxfile.py
 ^src/a2a/grpc/
+.pre-commit-config.yaml

.pre-commit-config.yaml

@@ -0,0 +1,62 @@
+---
+repos:
+  # ===============================================
+  # Pre-commit standard hooks (general file cleanup)
+  # ===============================================
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.6.0
+    hooks:
+      - id: trailing-whitespace  # Removes extra whitespace at the end of lines
+      - id: end-of-file-fixer  # Ensures files end with a newline
+      - id: check-yaml  # Checks YAML file syntax (before formatting)
+      - id: check-toml  # Checks TOML file syntax (before formatting)
+      - id: check-added-large-files  # Prevents committing large files
+        args: [--maxkb=500]  # Example: Limit to 500KB
+      - id: check-merge-conflict  # Checks for merge conflict strings
+      - id: detect-private-key  # Detects accidental private key commits
+
+  # Formatter and linter for TOML files
+  - repo: https://github.com/ComPWA/taplo-pre-commit
+    rev: v0.9.3
+    hooks:
+      - id: taplo-format
+      - id: taplo-lint
+
+  # YAML files
+  - repo: https://github.com/lyz-code/yamlfix
+    rev: 1.16.1
+    hooks:
+      - id: yamlfix
+
+  # ===============================================
+  # Python Hooks
+  # ===============================================
+  # no_implicit_optional for ensuring explicit Optional types
+  - repo: https://github.com/hauntsaninja/no_implicit_optional
+    rev: '1.4'
+    hooks:
+      - id: no_implicit_optional
+        args: [--use-union-or]
+
+  # Pyupgrade for upgrading Python syntax to newer versions
+  - repo: https://github.com/asottile/pyupgrade
+    rev: v3.20.0
+    hooks:
+      - id: pyupgrade
+        args: [--py310-plus]  # Target Python 3.10+ syntax, matching project's target
+
+  # Autoflake for removing unused imports and variables
+  - repo: https://github.com/pycqa/autoflake
+    rev: v2.3.1
+    hooks:
+      - id: autoflake
+        args: [--in-place, --remove-all-unused-imports]
+
+  # Ruff for linting and formatting
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.12.0
+    hooks:
+      - id: ruff  # Linter: applies auto-fixable linting rules
+        args: [--fix, --exit-zero]  # Apply fixes, and exit with 0 even if files were modified
+      - id: ruff-format  # Formatter: similar to Black, handles consistent code style
+        args: []  # Check formatting, but do not auto-fix during commit; fail if not formatted

.ruff.toml

@@ -4,7 +4,7 @@
 #
 # This file follows the standards in Google Python Style Guide
 # https://google.github.io/styleguide/pyguide.html
-#  
+#
 
 line-length = 80 # Google Style Guide §3.2: 80 columns
 indent-width = 4 # Google Style Guide §3.4: 4 spaces
@@ -102,7 +102,6 @@ lines-between-types = 1
 [lint.pydocstyle]
 convention = "google"
 ignore-decorators = ["typing.overload", "abc.abstractmethod"]
-ignore-var-parameters = true
 
 [lint.flake8-annotations]
 mypy-init-return = true

pyproject.toml

@@ -82,6 +82,7 @@ dev = [
   "uv-dynamic-versioning>=0.8.2",
   "types-protobuf",
   "types-requests",
+  "pre-commit",
 ]
 
 [[tool.uv.index]]