Ignore anonymous namespaces in the snapshot (#55844)

Summary:
Pull Request resolved: #55844

Changelog: [Internal]

Updates the C++ API snapshot generator not to include anonymous namespaces in the snapshot since those have internal linkage.

Reviewed By: cipolleschi

Differential Revision: D94901508

fbshipit-source-id: f025f69e4d9cc6cc42fa99974d596eb223e8da1c

Author: j-piasecki

scripts/cxx-api/parser/main.py

@@ -526,6 +526,11 @@ def build_snapshot(xml_dir: str) -> Snapshot:
                             f"Unknown class visibility: {visibility} in {compound_object.location.file}"
                         )
             elif compound_object.kind == "namespace":
+                # Skip anonymous namespaces (internal linkage, not public API).
+                # Doxygen encodes them with a '@' prefix in the compound name.
+                if "@" in compound_object.compoundname:
+                    continue
+
                 namespace_scope = snapshot.create_or_get_namespace(
                     compound_object.compoundname
                 )

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

@@ -0,0 +1,3 @@
+class test::Clss {
+  public void hello();
+}

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

@@ -0,0 +1,24 @@
+/*
+ * 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 {
+enum class InternalEnum {
+  A,
+  B,
+};
+} // namespace
+
+namespace test {
+
+class Clss {
+ public:
+  void hello();
+};
+
+} // namespace test