Remove incorrect qualification from function parameters (#55971)

Summary:
Pull Request resolved: #55971

Changelog: [Internal]

Doxygen incorrectly transforms parameter names to references if they match a member. This diff strips the resulting invalid qualification from the type.

Reviewed By: cipolleschi

Differential Revision: D95548542

fbshipit-source-id: c1e475f10e07af6a4076336cab0d3cbe0da342e5

Author: j-piasecki

scripts/cxx-api/parser/utils/argument_parsing.py

@@ -297,6 +297,13 @@ def _parse_single_argument(arg: str) -> Argument:
             )
         ):
             return (qualifiers, base_arg, None, default_value)
+        # C++ parameter names cannot contain "::". Doxygen may
+        # incorrectly cross-reference a parameter name to a member
+        # variable, producing a qualified path (e.g. "bool
+        # ns::Class::isActive" instead of "bool isActive"). Strip
+        # the namespace prefix to recover the original name.
+        if "::" in potential_name:
+            potential_name = potential_name.rsplit("::", 1)[-1]
         return (qualifiers, prefix, potential_name, default_value)
     else:
         return (qualifiers, base_arg, None, default_value)

scripts/cxx-api/tests/snapshots/should_not_qualify_parameter_names_in_function_types/snapshot.api

@@ -0,0 +1,5 @@
+class test::Tracer {
+  public bool isActive;
+  public uint32_t subscribe(test::Tracer::StateCallback callback);
+  public using StateCallback = void(*)(bool isActive);
+}

scripts/cxx-api/tests/snapshots/should_not_qualify_parameter_names_in_function_types/test.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+namespace test {
+
+class Tracer {
+ public:
+  bool isActive;
+  using StateCallback = void (*)(bool isActive);
+  uint32_t subscribe(StateCallback callback);
+};
+
+} // namespace test

scripts/cxx-api/tests/test_parse_arg_string.py

@@ -374,6 +374,33 @@ def test_full_complex_signature(self):
         self.assertTrue(mods.is_noexcept)
         self.assertTrue(mods.is_override)
 
+    # =========================================================================
+    # Qualified parameter names (Doxygen cross-reference cleanup)
+    # =========================================================================
+
+    def test_qualified_parameter_name_stripped(self):
+        """Parameter names containing '::' should be stripped to base name.
+
+        Doxygen may incorrectly cross-reference parameter names to member
+        variables, producing qualified paths like 'ns::Class::paramName'.
+        C++ parameter names cannot contain '::', so the qualification must
+        be stripped to just the base name.
+        """
+        args, mods = parse_arg_string(
+            "(bool facebook::react::PerformanceTracer::isTracing)"
+        )
+        self.assertEqual(args, [(None, "bool", "isTracing", None)])
+
+    def test_qualified_parameter_name_simple(self):
+        """Simple qualified parameter name: test::Foo::value"""
+        args, mods = parse_arg_string("(int test::Foo::value)")
+        self.assertEqual(args, [(None, "int", "value", None)])
+
+    def test_unqualified_parameter_name_unchanged(self):
+        """Regular parameter names without '::' should not be affected."""
+        args, mods = parse_arg_string("(bool isActive)")
+        self.assertEqual(args, [(None, "bool", "isActive", None)])
+
 
 if __name__ == "__main__":
     unittest.main()