Add arguments to type hints (#56)

* Add arguments to type hints

* Add pr link

* Use T consistently as instance of a config class

CHANGELOG.md

@@ -18,6 +18,12 @@ Whenever there is a need to break compatibility, it is announced here in the cha
 
 ## [Unreleased](https://github.com/hynek/environ-config/compare/23.1.0...HEAD)
 
+### Fixed
+
+- Type hints for `environ.config()` now allow for arguments (e.g. `@environ.config(prefix="")`).
+  [#56](https://github.com/hynek/environ-config/issues/56)
+
+
 ## [23.1.0](https://github.com/hynek/environ-config/compare/22.1.0...23.1.0) - 2023-01-27
 
 ### Backwards-incompatible Changes

src/environ/_environ_config.py

@@ -17,7 +17,7 @@
 import logging
 import os
 
-from typing import Any, Callable, TypeVar
+from typing import Any, Callable, TypeVar, overload
 
 import attr
 
@@ -60,13 +60,30 @@ class Raise:
 T = TypeVar("T")
 
 
+@overload
+def config(
+    *,
+    prefix: str | Sentinel = PREFIX_NOT_SET,
+    from_environ: str = "from_environ",
+    generate_help: str = "generate_help",
+    frozen: bool = False,
+) -> Callable[[type[T]], type[T]]:
+    ...
+
+
+@overload
+def config(maybe_cls: type[T]) -> type[T]:
+    ...
+
+
 def config(
     maybe_cls: type[T] | None = None,
+    *,
     prefix: str | Sentinel = PREFIX_NOT_SET,
     from_environ: str = "from_environ",
     generate_help: str = "generate_help",
     frozen: bool = False,
-) -> T:
+) -> type[T] | Callable[[type[T]], type[T]]:
     """
     Make a class a configuration class.
 

typing_examples.py

@@ -58,3 +58,13 @@ def takes_sub(s: Config.Sub) -> int:
 ds: str = cfg.d_secret
 vs: str = cfg.v_secret
 as_: str = cfg.a_secret
+
+
+@environ.config(prefix="")
+class ConfigNoPrefix:
+    test_var = environ.var()
+
+
+@environ.config()
+class ConfigEmptyParens:
+    test_var = environ.var()