Add ty type checking and fix typing issues

.github/workflows/ci.yml

@@ -36,6 +36,8 @@ jobs:
       run: ruff format --check
     - name: Check lints
       run: ruff check
+    - name: Check types
+      run: uv run --group dev ty check clr_loader
 
   test:
     runs-on: ${{ matrix.os.instance }}

.gitignore

@@ -64,10 +64,8 @@ target/
 # pyenv
 .python-version
 
-# mypy
-.mypy_cache/
-.dmypy.json
-dmypy.json
+# ty
+.ty_cache/
 
 # Pyre type checker
 .pyre/

Justfile

@@ -13,13 +13,15 @@ test:
 lint:
     uv run ruff check
 
+typecheck:
+    uv run ty check clr_loader
+
 format:
     uv run ruff format
 
-check: lint test
+check: lint typecheck test
     uv run ruff format --check
 
 docs output="doc/html/":
     uv run --group doc sphinx-build doc/ doc/html/
 
-

clr_loader/ffi/__init__.py

@@ -72,7 +72,8 @@ def _path_to_version(path: Path) -> tuple[int, int, int]:
         # Handle pre-release versions like "10.0.0-rc.1" by taking only the version part
         version_part = name.split("-")[0]
         res = list(map(int, version_part.split(".")))
-        return tuple(res + [0, 0, 0])[:3]
+        v = (res + [0, 0, 0])[:3]
+        return (v[0], v[1], v[2])
     except Exception:  # noqa
         return (0, 0, 0)
 

clr_loader/hostfxr.py

@@ -1,6 +1,7 @@
 import sys
 from collections.abc import Generator
 from pathlib import Path
+from typing import Any
 
 from .ffi import ffi, load_hostfxr
 from .types import Runtime, RuntimeInfo, StrOrPath
@@ -144,7 +145,7 @@ def info(self):
 def _get_handle_for_runtime_config(
     dll, dotnet_root: StrOrPath, runtime_config: StrOrPath
 ):
-    params = ffi.new("hostfxr_initialize_parameters*")
+    params: Any = ffi.new("hostfxr_initialize_parameters*")
     params.size = ffi.sizeof("hostfxr_initialize_parameters")
     # params.host_path = ffi.new("char_t[]", encode(sys.executable))
     params.host_path = ffi.NULL
@@ -164,7 +165,7 @@ def _get_handle_for_runtime_config(
 def _get_handle_for_dotnet_command_line(
     dll, dotnet_root: StrOrPath, entry_dll: StrOrPath
 ):
-    params = ffi.new("hostfxr_initialize_parameters*")
+    params: Any = ffi.new("hostfxr_initialize_parameters*")
     params.size = ffi.sizeof("hostfxr_initialize_parameters")
     params.host_path = ffi.NULL
     dotnet_root_p = ffi.new("char_t[]", encode(str(Path(dotnet_root))))
@@ -209,4 +210,7 @@ def encode(string: str):
         return string.encode("utf8")
 
     def decode(char_ptr) -> str:
-        return ffi.string(char_ptr).decode("utf8")
+        res = ffi.string(char_ptr)
+        if isinstance(res, bytes):
+            return res.decode("utf8")
+        return str(res)

clr_loader/mono.py

@@ -186,7 +186,12 @@ def initialize(
 
     build = _MONO.mono_get_runtime_build_info()
     _check_result(build, "Failed to get Mono version")
-    ver_str = ffi.string(build).decode("utf8")  # e.g. '6.12.0.122 (tarball)'
+    build_bytes = ffi.string(build)
+    ver_str = (
+        build_bytes.decode("utf8")
+        if isinstance(build_bytes, bytes)
+        else str(build_bytes)
+    )  # e.g. '6.12.0.122 (tarball)'
 
     ver = re.match(r"^(?P<major>\d+)\.(?P<minor>\d+)\.[\d.]+", ver_str)
     if ver is not None:

clr_loader/netfx.py

@@ -10,15 +10,16 @@
 
 class NetFx(Runtime):
     def __init__(self, domain: str | None = None, config_file: Path | None = None):
-        self._domain: str | None = None
+        self._domain: Any = None
 
         initialize()
+        config_file_s: Any
         if config_file is not None:
             config_file_s = str(config_file).encode("utf8")
         else:
             config_file_s = ffi.NULL
 
-        domain_s = domain.encode("utf8") if domain else ffi.NULL
+        domain_s: Any = domain.encode("utf8") if domain else ffi.NULL
 
         self._domain_name: str | None = domain
         self._config_file: Path | None = config_file

clr_loader/util/find.py

@@ -161,31 +161,31 @@ def _find_mono_unix(
         if candidate.exists():
             return candidate
 
-    if res := find_library(unix_name):
-        return Path(res)
+    if lib_path := find_library(unix_name):
+        return Path(lib_path)
 
     if macos:
-        res = (
+        candidate = (
             Path("/Library/Frameworks/Mono.framework/Versions/Current/lib")
             / lib_filename
         )
-        if res.exists():
-            return res
+        if candidate.exists():
+            return candidate
 
         # Use HOMEBREW_PREFIX environment variable if available
         if homebrew_prefix := os.environ.get("HOMEBREW_PREFIX"):
-            res = Path(homebrew_prefix) / "opt/mono/lib" / lib_filename
-            if res.exists():
-                return res
+            candidate = Path(homebrew_prefix) / "opt/mono/lib" / lib_filename
+            if candidate.exists():
+                return candidate
 
         # Check for native Apple Silicon (arm64)
         if platform.machine() == "arm64":
-            res = Path("/opt/homebrew/opt/mono/lib") / lib_filename
-            if res.exists():
-                return res
+            candidate = Path("/opt/homebrew/opt/mono/lib") / lib_filename
+            if candidate.exists():
+                return candidate
         else:
-            res = Path("/usr/local/opt/mono/lib") / lib_filename
-            if res.exists():
-                return res
+            candidate = Path("/usr/local/opt/mono/lib") / lib_filename
+            if candidate.exists():
+                return candidate
 
     raise RuntimeError("Could not find libmono")

pyproject.toml

@@ -33,8 +33,10 @@ Documentation = "https://pythonnet.github.io/clr-loader/"
 
 [dependency-groups]
 dev = [
+    "ty >=0.0.1",
     "pytest >=9.0, <10.0",
     "ruff >=0.15",
+    "types-cffi",
 ]
 doc = ["furo >=2025.0", "sphinx >=9.0, <10.0"]