feat: allow @staticmethod to be used with @corgyparser

corgy/_corgy.py

@@ -598,6 +598,9 @@ def corgyparser(var_name: str) -> Callable[[Callable[[str], Any]], _CorgyParser]
         This decorator is only available on Python 3.9 or higher.
 
     To use a custom function for parsing an argument with `Corgy`, use this decorator.
+    Parsing functions must be static, and should only accept a single string argument.
+    Decorating the function with `@staticmethod` is optional, but prevents type errors.
+    `@corgyparser` must be the final decorator in the decorator chain.
 
     Args:
         var_name: The argument associated with the decorated parser.
@@ -607,8 +610,10 @@ def corgyparser(var_name: str) -> Callable[[Callable[[str], Any]], _CorgyParser]
         class A(Corgy):
             time: tuple[int, int, int]
             @corgyparser("time")
+            @staticmethod
             def parse_time(s):
                 return tuple(map(int, s.split(":")))
+
     """
     if not isinstance(var_name, str):
         raise TypeError(
@@ -617,6 +622,10 @@ def parse_time(s):
         )
 
     def wrapper(var_name, fparse):
+        if isinstance(fparse, staticmethod):
+            fparse = fparse.__func__
+        if not callable(fparse):
+            raise TypeError("corgyparser can only decorate static functions")
         return _CorgyParser(var_name, fparse)
 
     return partial(wrapper, var_name)

docs/corgy.md

@@ -277,6 +277,9 @@ Decorate a function as a custom parser for a variable.
 **NOTE**: This decorator is only available on Python 3.9 or higher.
 
 To use a custom function for parsing an argument with `Corgy`, use this decorator.
+Parsing functions must be static, and should only accept a single string argument.
+Decorating the function with `@staticmethod` is optional, but prevents type errors.
+`@corgyparser` must be the final decorator in the decorator chain.
 
 
 * **Parameters**
@@ -290,6 +293,7 @@ Example:
 class A(Corgy):
     time: tuple[int, int, int]
     @corgyparser("time")
+    @staticmethod
     def parse_time(s):
         return tuple(map(int, s.split(":")))
 ```

tests/test_corgy.py

@@ -723,8 +723,6 @@ class C(Corgy):
 class TestCorgyCustomParsers(unittest.TestCase):
     """Tests to check usage of the @corgyparser decorator."""
 
-    # pylint: disable=no-self-argument, unused-variable
-
     def test_corgyparser_raises_if_not_passed_name(self):
         with self.assertRaises(TypeError):
 
@@ -735,19 +733,19 @@ def spam():
     def test_corgy_raises_if_corgyparser_target_invalid(self):
         with self.assertRaises(TypeError):
 
-            class A(Corgy):
+            class _(Corgy):
                 x: int
 
                 @corgyparser("y")
-                def parsex(s: str):  # type: ignore
+                def parsex(s: str):  # type: ignore # pylint: disable=no-self-argument
                     return 0
 
     def test_add_args_handles_corgyparser(self):
         class C(Corgy):
             x: Annotated[int, "x"]
 
             @corgyparser("x")
-            def parsex(s: str):  # type: ignore
+            def parsex(s: str):  # type: ignore # pylint: disable=no-self-argument
                 return 0
 
         parser = argparse.ArgumentParser()
@@ -762,7 +760,7 @@ class C(Corgy):
             x: int = 1
 
             @corgyparser("x")
-            def parsex(s: str):  # type: ignore
+            def parsex(s: str):  # type: ignore # pylint: disable=no-self-argument
                 return 0
 
         parser = argparse.ArgumentParser()
@@ -777,7 +775,7 @@ class C(Corgy):
             x: int
 
             @corgyparser("x")
-            def parsex(s: str):  # type: ignore
+            def parsex(s: str):  # type: ignore # pylint: disable=no-self-argument
                 return 0
 
         getattr(C, "__parsers")["x"] = MagicMock()
@@ -793,7 +791,7 @@ class C(Corgy):
             x: int
 
             @corgyparser("x")
-            def parsex(s: str):  # type: ignore
+            def parsex(s: str):  # type: ignore # pylint: disable=no-self-argument
                 return -1
 
         parser = argparse.ArgumentParser()
@@ -802,3 +800,30 @@ def parsex(s: str):  # type: ignore
 
         args = C.parse_from_cmdline(parser)
         self.assertEqual(args.x, -1)
+
+    def test_corgyparser_allows_decorating_staticmethod(self):
+        class C(Corgy):
+            x: int
+
+            @corgyparser("x")
+            @staticmethod
+            def parsex(s: str):
+                return 0
+
+        parser = argparse.ArgumentParser()
+        orig_parse_args = argparse.ArgumentParser.parse_args
+        parser.parse_args = lambda: orig_parse_args(parser, ["--x", "test"])
+
+        c = C.parse_from_cmdline(parser)
+        self.assertEqual(c.x, 0)
+
+    def test_corgyparser_raises_if_decorating_non_staticmethod(self):
+        with self.assertRaises(TypeError):
+
+            class _(Corgy):
+                x: int
+
+                @corgyparser("x")
+                @classmethod
+                def parsex(cls, s: str):
+                    return 0