Fix function pointer param args being qualified to outer class (#56217)

Summary:
Pull Request resolved: #56217

Changelog: [Internal]

Doxygen may incorrectly cross-reference parameter names inside function
pointer types to member variables of the enclosing class. For example,
`void (*cb)(const void* data)` inside a class that has a `data` member
would produce `const void* Class::data` instead of
`const void* data` in the snapshot. This diff addresses two issues:

1. In `get_doxygen_params`, re-parse function pointer type strings
   through `parse_type_with_argstrings` which delegates to
   `_parse_single_argument` that already strips "::" from parameter
   names.
2. In `parse_type_with_argstrings`, recognize complex declarator groups
   starting with `*` or `&` (e.g. `*(*fp)(int)`) as non-argument-list
   parenthesized sections, preventing incorrect name extraction from
   nested function pointer declarators.

Reviewed By: cipolleschi

Differential Revision: D98118629

fbshipit-source-id: a8532e2adaec1dd2b50be8a20eae1068ac49d548

Author: j-piasecki

scripts/cxx-api/parser/builders.py

@@ -41,7 +41,12 @@
     resolve_linked_text_name,
     split_specialization,
 )
-from .utils.argument_parsing import _find_matching_angle, _split_arguments
+from .utils.argument_parsing import (
+    _find_matching_angle,
+    _split_arguments,
+    format_parsed_type,
+    parse_type_with_argstrings,
+)
 
 
 @dataclass
@@ -307,6 +312,16 @@ def get_doxygen_params(
             if param.get_type()
             else ""
         )
+
+        # Doxygen may incorrectly cross-reference parameter names inside
+        # inline function pointer types to member variables of the enclosing
+        # class, producing qualified paths like "const void*
+        # ns::Class::data" instead of "const void* data".  Re-parse the
+        # type through parse_type_with_argstrings which delegates to
+        # _parse_single_argument — that already strips "::" from names.
+        segments = parse_type_with_argstrings(param_type)
+        if len(segments) > 1:
+            param_type = format_parsed_type(segments)
         param_name = param.declname or param.defname or None
         param_default = (
             resolve_linked_text_name(param.defval)[0].strip() if param.defval else None

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

@@ -530,6 +530,14 @@ def parse_type_with_argstrings(
                 i = close + 1
                 continue
 
+            # Complex declarator starting with * or &, e.g. *(*fp)(int)
+            # in "int(*(*fp)(int))(double)".  Argument lists never start
+            # with pointer/reference characters.
+            if stripped and stripped[0] in ("*", "&"):
+                current_text.append(type_str[i : close + 1])
+                i = close + 1
+                continue
+
             # Try to parse as a function argument list
             args: list[Argument] = []
             if stripped:

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

@@ -0,0 +1,4 @@
+class test::Runtime {
+  public int data;
+  public virtual void getStringData(void* ctx, void(*)(void* ctx, bool ascii, const void* data, size_t num) cb);
+}

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

@@ -0,0 +1,18 @@
+/*
+ * 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 Runtime {
+ public:
+  int data;
+  virtual void getStringData(void *ctx, void (*cb)(void *ctx, bool ascii, const void *data, size_t num));
+};
+
+} // namespace test