feat/stubgen: add preliminary $Cxx.name support

LICENSE

@@ -0,0 +1,7 @@
+Copyright 2026 NCBM
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

src/capnp_stubgen/gen_enum.py

@@ -7,7 +7,7 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
-from .utils import NodeDict
+from .utils import NodeDict, get_cxx_name
 
 if TYPE_CHECKING:
     from .emitter import Emitter
@@ -30,7 +30,7 @@ def generate_enum(
 
     literals: list[str] = []
     for e in enumerants:
-        literals.append(f'"{e["name"]}"')
+        literals.append(f'"{get_cxx_name(e) or e["name"]}"')
 
     emitter.add_typing_import("Literal")
     line = f"Literal[{', '.join(literals)}]"

src/capnp_stubgen/gen_struct.py

@@ -16,7 +16,7 @@ from .gen_const import generate_const
 from .gen_enum import generate_enum
 from .gen_generic import generate_type_vars
 from .type_resolver import resolve_type
-from .utils import NodeDict, type_id_to_int
+from .utils import NodeDict, get_cxx_name, type_id_to_int
 
 if TYPE_CHECKING:
     from .emitter import Emitter
@@ -44,7 +44,7 @@ def generate_struct(
 
     # ── collect fields ─────────────────────────────────────────────────
     for field in struct_body.get("fields", []):
-        field_name: str = field["name"]
+        field_name: str = get_cxx_name(field) or field["name"]
         disc_value: int = field.get("discriminantValue", _NO_DISCRIMINANT)
 
         if "slot" in field:
@@ -112,7 +112,8 @@ def generate_struct(
             generate_const(emitter, nt, registry)
 
     for field_name, type_str in non_union_fields:
-        emitter.add_field(field_name, type_str)
+        default = "None" if type_str == "None" else None
+        emitter.add_field(field_name, type_str, default=default)
 
     if discriminant_count > 0 and union_fields:
         _generate_union_methods(emitter, union_fields)

src/capnp_stubgen/schema_walker.py

@@ -7,7 +7,7 @@ building a ``TypeRegistry`` that maps type IDs to ``TypeInfo``.
 from __future__ import annotations
 
 from .models import TypeInfo, TypeRegistry
-from .utils import NodeDict, get_display_name, get_node_kind, type_id_to_int
+from .utils import NodeDict, get_cxx_name, get_display_name, get_node_kind, type_id_to_int
 
 
 _GENERATABLE_KINDS = frozenset({"struct", "enum", "interface", "const"})
@@ -35,7 +35,7 @@ def build_type_registry(
             continue
 
         type_id = type_id_to_int(node["id"])
-        name = get_display_name(node)
+        name = get_cxx_name(node) or get_display_name(node)
         scope_id = node.get("scopeId", "0")
         parent_id = type_id_to_int(scope_id) if scope_id != "0" else None
 
@@ -117,7 +117,7 @@ def _build_scoped_name(
             break
 
         if get_node_kind(node) != "file":
-            parts.append(get_display_name(node))
+            parts.append(get_cxx_name(node) or get_display_name(node))
 
         scope_id_str = node.get("scopeId", "0")
         scope_id = int(scope_id_str) if scope_id_str != "0" else 0

src/capnp_stubgen/utils.py

@@ -38,3 +38,22 @@ def get_node_kind(node: NodeDict) -> str:
 def type_id_to_int(type_id: str) -> int:
     """Convert a type ID string (from dict) to an integer."""
     return int(type_id)
+
+
+# Annotation IDs from c++.capnp
+_CXX_NAME_ANNOTATION_ID = 17466269397259751886  # 0xf2466592b7084e81
+
+
+def get_cxx_name(node: NodeDict) -> str | None:
+    """Return the ``$Cxx.name`` annotation value if present on a node."""
+    try:
+        for annot in node.get("annotations", []):
+            if annot.get("id") == _CXX_NAME_ANNOTATION_ID:
+                val = annot.get("value")
+                if isinstance(val, dict):
+                    text = val.get("text", "")
+                    if isinstance(text, str):
+                        return text
+    except Exception:
+        pass
+    return None

tests/schemas/test_stubs.py

@@ -15,7 +15,7 @@ _HERE = Path(__file__).parent
 if str(_HERE) not in sys.path:
     sys.path.insert(0, str(_HERE))
 
-import capnp  # pyright: ignore[reportMissingTypeStubs, reportUnusedImport]  # activates import hook
+import capnp  # pyright: ignore[reportMissingTypeStubs]  # activates import hook
 import test_generics_capnp
 import test_interface_capnp
 import test_nested_capnp
@@ -95,9 +95,22 @@ class TestAddressBookStub:
         assert ab.people is not None
 
 
-# dummy.capnp runtime tests skipped — its annotation imports (c.capnp,
+class TestDummyStub:
-# c++.capnp) cause pycapnp's C++ SchemaParser to SIGABRT.  The generated
+    """dummy.capnp — comprehensive test schema."""
-# .pyi passes static type-checking and `capnp compile -opy` succeeds.
+
+    def test_all_types_loads(self) -> None:
+        from pathlib import Path
+        parser = capnp.SchemaParser()  # pyright: ignore[reportAttributeAccessIssue]
+        m = parser.load(str(Path(__file__).parent / "dummy.capnp"))
+        msg = m.TestAllTypes.new_message(textField="hello", int32Field=42)
+        assert msg.textField == "hello"
+
+    def test_unions(self) -> None:
+        from pathlib import Path
+        parser = capnp.SchemaParser()  # pyright: ignore[reportAttributeAccessIssue]
+        m = parser.load(str(Path(__file__).parent / "dummy.capnp"))
+        u = m.TestUnion.new_message()
+        assert u is not None
 
 
 # Note: multi/consumer.capnp cross-file import test skipped —