feat: add ty type checker alongside mypy (#77)

Add Astral's ty type checker (written in Rust, 10-100x faster than mypy)
as a second type checking layer. Both run in pre-commit and CI.

Fixed type issues caught by ty:
- config.py: explicit Host constructor to avoid dict unpacking issues
- executor.py: wrap subprocess.run in closure for asyncio.to_thread
- api.py: use getattr for Jinja TemplateModule macro access
- test files: fix playwright driver_path tuple handling, pytest rootpath typing

.github/check_readme_commands.py

@@ -24,7 +24,7 @@ def get_all_commands(typer_app: typer.Typer, prefix: str = "cf") -> set[str]:
             continue
         name = command.name
         if not name and command.callback:
-            name = command.callback.__name__
+            name = getattr(command.callback, "__name__", None)
         if name:
             commands.add(f"{prefix} {name}")
 

.pre-commit-config.yaml

@@ -25,13 +25,18 @@ repos:
         args: [--fix]
       - id: ruff-format
 
-  - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.14.0
+  - repo: local
     hooks:
       - id: mypy
-        exclude: ^docs/demos/
-        additional_dependencies:
-          - pydantic>=2.0.0
-          - typer>=0.9.0
-          - asyncssh>=2.14.0
-          - types-PyYAML
+        name: mypy (type checker)
+        entry: uv run mypy src tests
+        language: system
+        types: [python]
+        pass_filenames: false
+
+      - id: ty
+        name: ty (type checker)
+        entry: uv run ty check
+        language: system
+        types: [python]
+        pass_filenames: false

pyproject.toml

@@ -164,9 +164,19 @@ exclude_lines = [
     'if __name__ == "__main__":',
 ]
 
+[tool.ty.environment]
+python-version = "3.11"
+
+[tool.ty.src]
+exclude = [
+    "hatch_build.py",  # Build-time only, hatchling not in dev deps
+    "docs/demos/**",   # Demo scripts with local conftest imports
+]
+
 [dependency-groups]
 dev = [
     "mypy>=1.19.0",
+    "ty>=0.0.1a13",
     "pre-commit>=4.5.0",
     "pytest>=9.0.2",
     "pytest-asyncio>=1.3.0",

src/compose_farm/config.py

@@ -122,7 +122,11 @@ def _parse_hosts(raw_hosts: dict[str, str | dict[str, str | int]]) -> dict[str,
             hosts[name] = Host(address=value)
         else:
             # Full form: hostname: {address: ..., user: ..., port: ...}
-            hosts[name] = Host(**value)
+            hosts[name] = Host(
+                address=str(value.get("address", "")),
+                user=str(value["user"]) if "user" in value else getpass.getuser(),
+                port=int(value["port"]) if "port" in value else 22,
+            )
     return hosts
 
 

src/compose_farm/executor.py

@@ -238,9 +238,13 @@ async def _run_ssh_command(
     if raw:
         # Use native ssh with TTY for proper progress bar rendering
         ssh_args = build_ssh_command(host, command, tty=True)
+
+        def run_ssh() -> subprocess.CompletedProcess[bytes]:
+            return subprocess.run(ssh_args, check=False, env=get_ssh_env())
+
         # Run in thread to avoid blocking the event loop
         # Use get_ssh_env() to auto-detect SSH agent socket
-        result = await asyncio.to_thread(subprocess.run, ssh_args, check=False, env=get_ssh_env())
+        result = await asyncio.to_thread(run_ssh)
         return CommandResult(
             service=service,
             exit_code=result.returncode,

src/compose_farm/web/routes/api.py

@@ -8,7 +8,10 @@ import json
 import shlex
 from datetime import UTC, datetime
 from pathlib import Path
-from typing import Annotated, Any
+from typing import TYPE_CHECKING, Annotated, Any
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
 
 import asyncssh
 import yaml
@@ -175,8 +178,9 @@ def _render_containers(
     templates = get_templates()
     template = templates.env.get_template("partials/containers.html")
     module = template.make_module()
-    result: str = module.host_containers(service, host, containers, show_header=show_header)
-    return result
+    # TemplateModule exports macros as attributes; getattr keeps type checkers happy
+    host_containers: Callable[..., str] = getattr(module, "host_containers")  # noqa: B009
+    return host_containers(service, host, containers, show_header=show_header)
 
 
 @router.get("/service/{name}/containers", response_class=HTMLResponse)

tests/test_cli_lifecycle.py

@@ -16,7 +16,9 @@ def _make_config(tmp_path: Path, services: dict[str, str] | None = None) -> Conf
     compose_dir = tmp_path / "compose"
     compose_dir.mkdir()
 
-    svc_dict = services or {"svc1": "host1", "svc2": "host2"}
+    svc_dict: dict[str, str | list[str]] = (
+        dict(services) if services else {"svc1": "host1", "svc2": "host2"}
+    )
     for svc in svc_dict:
         svc_dir = compose_dir / svc
         svc_dir.mkdir()

tests/web/test_htmx_browser.py

@@ -44,7 +44,9 @@ def _browser_available() -> bool:
     try:
         from playwright._impl._driver import compute_driver_executable
 
-        driver_path = compute_driver_executable()
+        driver_info = compute_driver_executable()
+        # compute_driver_executable returns (driver_path, browser_path) tuple
+        driver_path = driver_info[0] if isinstance(driver_info, tuple) else driver_info
         return Path(driver_path).exists()
     except Exception:
         return False
@@ -63,7 +65,7 @@ pytestmark = [
 @pytest.fixture(scope="session")
 def vendor_cache(request: pytest.FixtureRequest) -> Path:
     """Download CDN assets once and cache to disk for faster tests."""
-    cache_dir = Path(request.config.rootdir) / ".pytest_cache" / "vendor"
+    cache_dir = Path(request.config.rootpath) / ".pytest_cache" / "vendor"
     return ensure_vendor_cache(cache_dir)
 
 

uv.lock

@@ -260,6 +260,7 @@ dev = [
     { name = "pytest-playwright" },
     { name = "pytest-xdist" },
     { name = "ruff" },
+    { name = "ty" },
     { name = "types-pyyaml" },
     { name = "uvicorn", extra = ["standard"] },
     { name = "websockets" },
@@ -292,6 +293,7 @@ dev = [
     { name = "pytest-playwright", specifier = ">=0.7.0" },
     { name = "pytest-xdist", specifier = ">=3.0.0" },
     { name = "ruff", specifier = ">=0.14.8" },
+    { name = "ty", specifier = ">=0.0.1a13" },
     { name = "types-pyyaml", specifier = ">=6.0.12.20250915" },
     { name = "uvicorn", extras = ["standard"], specifier = ">=0.27.0" },
     { name = "websockets", specifier = ">=12.0" },
@@ -1685,6 +1687,31 @@ wheels = [
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 ]
 
+[[package]]
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+wheels = [
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 name = "typer"
 version = "0.20.0"