ddsidl: fix dead Python-keyword check in getAllowedName

`keyword.iskeyword(name.lower)` was missing its call parentheses, so
the bound-method object `name.lower` was passed to `iskeyword` instead
of the lowered string. `iskeyword` always returned False, leaving the
Python-keyword arm of the check effectively dead — VSS signal names
that are Python keywords but NOT also C/IDL keywords (e.g. 'class',
'def', 'import', 'lambda') were emitted unprefixed and produced
syntactically invalid IDL.

Compute `name.lower()` once into a local, pass it to `iskeyword`
explicitly, and add a regression test in tests/test_ddsidl_naming.py
covering both the bug case (Python-only keywords) and the existing
behaviour (C/IDL keywords, normal names).

Author: SoundMatt

src/vss_tools/exporters/ddsidl.py

@@ -146,7 +146,15 @@
 
 
 def getAllowedName(name):
-    if name.lower() in c_keywords or name.lower() in idl_keywords or keyword.iskeyword(name.lower):
+    lower = name.lower()
+    # `keyword.iskeyword(name.lower)` (without call parens) passed a
+    # bound-method object to iskeyword instead of the lowered string,
+    # so iskeyword always returned False. VSS signals named with Python
+    # keywords that are NOT also C/IDL keywords (e.g. 'class', 'def',
+    # 'import', 'lambda') were therefore emitted unprefixed and produced
+    # syntactically invalid IDL. Compute lower once and pass it
+    # explicitly to iskeyword.
+    if lower in c_keywords or lower in idl_keywords or keyword.iskeyword(lower):
         return "_" + name
     else:
         return name

tests/test_ddsidl_naming.py

@@ -0,0 +1,55 @@
+# Copyright (c) 2026 Contributors to COVESA
+#
+# This program and the accompanying materials are made available under the
+# terms of the Mozilla Public License 2.0 which is available at
+# https://www.mozilla.org/en-US/MPL/2.0/
+#
+# SPDX-License-Identifier: MPL-2.0
+
+from vss_tools.exporters.ddsidl import getAllowedName
+
+
+class TestDdsIdlNaming:
+    """Tests for getAllowedName, which prefixes reserved-word identifiers."""
+
+    def test_passes_through_normal_names(self):
+        """Names that aren't reserved should be returned unchanged."""
+        assert getAllowedName("speed") == "speed"
+        assert getAllowedName("Vehicle") == "Vehicle"
+        assert getAllowedName("Foo123") == "Foo123"
+
+    def test_prefixes_python_keywords(self):
+        """Python reserved words should get a leading underscore.
+
+        Regression test: previously the keyword.iskeyword() call was missing
+        its parentheses on its argument (`name.lower` instead of
+        `name.lower()`), so a bound-method object was passed to iskeyword
+        instead of the lowered string. iskeyword returned False, so VSS
+        signals named with Python keywords that aren't also C/IDL keywords
+        (e.g. 'class', 'def', 'import', 'lambda') passed through silently
+        and ended up as raw identifiers in the generated IDL.
+        """
+        assert getAllowedName("class") == "_class"
+        assert getAllowedName("def") == "_def"
+        assert getAllowedName("import") == "_import"
+        assert getAllowedName("lambda") == "_lambda"
+        # Case-insensitive: same effect for differently-cased input.
+        assert getAllowedName("Class") == "_Class"
+        assert getAllowedName("CLASS") == "_CLASS"
+
+    def test_prefixes_idl_keywords(self):
+        """IDL reserved words should get a leading underscore."""
+        assert getAllowedName("interface") == "_interface"
+        assert getAllowedName("module") == "_module"
+        assert getAllowedName("attribute") == "_attribute"
+
+    def test_prefixes_c_keywords(self):
+        """C reserved words should get a leading underscore.
+
+        Some of these (`if`, `for`, `while`, `return`) are also Python
+        keywords, but C-keyword detection caught them already even with
+        the iskeyword bug.
+        """
+        assert getAllowedName("auto") == "_auto"
+        assert getAllowedName("typedef") == "_typedef"
+        assert getAllowedName("sizeof") == "_sizeof"