Don't let Resolver forget function_name

Author: wesselb

plum/function.py

@@ -88,7 +88,7 @@ def __init__(self, f: Callable, owner: Optional[str] = None) -> None:
 
         # Initialise pending and resolved methods.
         self._pending: List[Tuple[Callable, Optional[Signature], int]] = []
-        self._resolver = Resolver(function_name=self.__name__)
+        self._resolver = Resolver(self.__name__)
         self._resolved: List[Tuple[Callable, Signature, int]] = []
 
     @property
@@ -233,7 +233,7 @@ def clear_cache(self, reregister: bool = True) -> None:
 
             # Clear resolved.
             self._resolved = []
-            self._resolver = Resolver()
+            self._resolver = Resolver(self._resolver.function_name)
 
     def register(
         self, f: Callable, signature: Optional[Signature] = None, precedence=0

tests/test_function.py

@@ -612,3 +612,17 @@ def do(self, x: int):
     # Also test that `invoke` is wrapped, like above.
     assert A().do.invoke(int).__doc__ == "Docs"
     assert A.do.invoke(A, int).__doc__ == "Docs"
+
+
+def test_name_after_clearing_cache():
+    dispatch = Dispatcher()
+
+    @dispatch
+    def some_function_name(x: int):
+        pass
+
+    assert some_function_name._resolver.function_name == "some_function_name"
+
+    some_function_name.clear_cache()
+
+    assert some_function_name._resolver.function_name == "some_function_name"