stubgen.py: handle method aliases similarly to function aliases (#735)

Author: wojdyr

docs/changelog.rst

@@ -34,6 +34,10 @@ Version TBD (unreleased)
   <https://github.com/wjakob/nanobind/pull/939>`__, `#940
   <https://github.com/wjakob/nanobind/pull/940>`__).
 
+- The stub generator now detects method aliases and preserves this information
+  instead of duplicating the definition. (PR `#735
+  <https://github.com/wjakob/nanobind/pull/735>`__).
+
 - Added support for binding functions that accept a ``std::variant<...>`` that
   is not default-constructible (because its first alternative isn't). (PR `#987
   <https://github.com/wjakob/nanobind/pull/987>`__).

ext/robin_map

@@ -395,19 +395,19 @@ def put_function(self, fn: Callable[..., Any], name: Optional[str] = None, paren
             self.write_ln(f"{name} = {fn_name}\n")
             return
 
+        # Special handling for nanobind functions with overloads
+        if type(fn).__module__ == "nanobind":
+            fn = cast(NbFunction, fn)
+            self.put_nb_func(fn, name)
+            return
+
         if isinstance(fn, staticmethod):
             self.write_ln("@staticmethod")
             fn = fn.__func__
         elif isinstance(fn, classmethod):
             self.write_ln("@classmethod")
             fn = fn.__func__
 
-        # Special handling for nanobind functions with overloads
-        if type(fn).__module__ == "nanobind":
-            fn = cast(NbFunction, fn)
-            self.put_nb_func(fn, name)
-            return
-
         if name is None:
             name = fn.__name__
             assert name
@@ -859,7 +859,7 @@ def put(self, value: object, name: Optional[str] = None, parent: Optional[object
             elif tp_mod == "nanobind":
                 if tp_name == "nb_method":
                     value = cast(NbFunction, value)
-                    self.put_nb_func(value, name)
+                    self.put_function(value, name)
                 elif tp_name == "nb_static_property":
                     value = cast(NbStaticProperty, value)
                     self.put_nb_static_property(name, value)

src/stubgen.py

@@ -60,6 +60,7 @@ NB_MODULE(test_typing_ext, m) {
     // Aliases to local functoins and types
     m.attr("FooAlias") = m.attr("Foo");
     m.attr("f_alias") = m.attr("f");
+    nb::type<Foo>().attr("lt_alias") = nb::type<Foo>().attr("__lt__");
 
     // Custom signature generation for classes and methods
     struct CustomSignature { int value; };

tests/test_typing.cpp

@@ -17,6 +17,8 @@ class Foo:
 
     def __ge__(self, arg: Foo, /) -> bool: ...
 
+    lt_alias = __lt__
+
 def f() -> None: ...
 
 def makeNestedClass() -> py_stub_test.AClass.NestedClass: ...