Use a match statement to dispatch on gherkin Child fields

pyproject.toml

@@ -96,6 +96,7 @@ lint.isort.required-imports = [
 
 [tool.coverage.report]
 exclude_lines = [
+    "pragma: no cover",
     "if TYPE_CHECKING:",
     "if typing\\.TYPE_CHECKING:",
 ]

src/pytest_bdd/parser.py

@@ -4,6 +4,7 @@
 import os.path
 import re
 import textwrap
+import warnings
 from collections import OrderedDict
 from collections.abc import Generator, Iterable, Mapping, Sequence
 from dataclasses import dataclass, field
@@ -492,12 +493,21 @@ def parse(self) -> Feature:
         )
 
         for child in feature_data.children:
-            if child.background:
-                feature.background = self.parse_background(child.background)
-            elif child.rule:
-                self._parse_and_add_rule(child.rule, feature)
-            elif child.scenario:
-                self._parse_and_add_scenario(child.scenario, feature)
+            match child.background or child.rule or child.scenario:
+                case GherkinBackground() as background:
+                    feature.background = self.parse_background(background)
+                case GherkinRule() as rule:
+                    self._parse_and_add_rule(rule, feature)
+                case GherkinScenario() as scenario:
+                    self._parse_and_add_scenario(scenario, feature)
+                case _:
+                    # An empty Child, or a child kind newer than this gherkin version;
+                    # skip it and warn instead of crashing, to keep working against
+                    # future gherkin releases that add new child types.
+                    warnings.warn(
+                        f"Unknown gherkin child skipped in {self.rel_filename!r}; consider upgrading pytest-bdd.",
+                        stacklevel=2,
+                    )
 
         return feature
 

tests/parser/test_parser.py

@@ -1,7 +1,12 @@
 from __future__ import annotations
 
+import textwrap
 from pathlib import Path
+from unittest.mock import patch
 
+import pytest
+
+from src.pytest_bdd import parser as parser_module
 from src.pytest_bdd.gherkin_parser import (
     Background,
     Cell,
@@ -851,3 +856,36 @@ def test_parser():
     )
 
     assert gherkin_doc == expected_document
+
+
+def test_feature_parser_warns_on_unknown_child_kinds(tmp_path):
+    """A Child with none of background/rule/scenario set is skipped with a warning.
+
+    The gherkin AST reserves the right to grow new child kinds; ``Child.from_dict``
+    would map such a child to an all-``None`` dataclass, and ``FeatureParser.parse``
+    must warn and skip it instead of crashing, so pytest-bdd keeps working against
+    future gherkin releases.
+    """
+    (tmp_path / "minimal.feature").write_text(
+        textwrap.dedent(
+            """\
+            Feature: Minimal
+              Scenario: A scenario
+                Given a step
+            """
+        )
+    )
+
+    real_get_gherkin_document = parser_module.get_gherkin_document
+
+    def get_gherkin_document_with_unknown_child(abs_filename: str, encoding: str = "utf-8") -> GherkinDocument:
+        document = real_get_gherkin_document(abs_filename, encoding)
+        document.feature.children.append(Child())
+        return document
+
+    with patch.object(parser_module, "get_gherkin_document", get_gherkin_document_with_unknown_child):
+        with pytest.warns(UserWarning, match="Unknown gherkin child"):
+            feature = parser_module.FeatureParser(str(tmp_path), "minimal.feature").parse()
+
+    assert list(feature.scenarios) == ["A scenario"]
+    assert feature.background is None