improve parser performance

src/pytest_bdd/parser.py

@@ -6,6 +6,7 @@
 import typing
 from collections import OrderedDict
 from dataclasses import dataclass, field
+from functools import cached_property
 from typing import cast
 
 from . import exceptions, types
@@ -318,9 +319,10 @@ def add_line(self, line: str) -> None:
         :param str line: Line of text - the continuation of the step name.
         """
         self.lines.append(line)
+        self._invalidate_full_name_cache()
 
-    @property
-    def name(self) -> str:
+    @cached_property
+    def full_name(self) -> str:
         multilines_content = textwrap.dedent("\n".join(self.lines)) if self.lines else ""
 
         # Remove the multiline quotes, if present.
@@ -334,9 +336,19 @@ def name(self) -> str:
         lines = [self._name] + [multilines_content]
         return "\n".join(lines).strip()
 
+    def _invalidate_full_name_cache(self) -> None:
+        """Invalidate the full_name cache."""
+        if "full_name" in self.__dict__:
+            del self.full_name
+
+    @property
+    def name(self) -> str:
+        return self.full_name
+
     @name.setter
     def name(self, value: str) -> None:
         self._name = value
+        self._invalidate_full_name_cache()
 
     def __str__(self) -> str:
         """Full step name including the type."""

tests/steps/test_common.py

@@ -4,7 +4,7 @@
 
 import pytest
 
-from pytest_bdd import given, parsers, then, when
+from pytest_bdd import given, parser, parsers, then, when
 from pytest_bdd.utils import collect_dumped_objects
 
 
@@ -316,3 +316,25 @@ def _(n):
 
     objects = collect_dumped_objects(result)
     assert objects == ["foo", ("foo parametrized", 1), "foo", ("foo parametrized", 2), "foo", ("foo parametrized", 3)]
+
+
+def test_step_name_is_cached():
+    """Test that the step name is cached and not re-computed eache time."""
+    step = parser.Step(name="step name", type="given", indent=8, line_number=3, keyword="Given")
+    assert step.name == "step name"
+
+    # manipulate the step name directly and validate the cache value is still returned
+    step._name = "incorrect step name"
+    assert step.name == "step name"
+
+    # change the step name using the property and validate the cache has been invalidated
+    step.name = "new step name"
+    assert step.name == "new step name"
+
+    # manipulate the step lines and validate the cache value is still returned
+    step.lines.append("step line 1")
+    assert step.name == "new step name"
+
+    # add a step line and validate the cache has been invalidated
+    step.add_line("step line 2")
+    assert step.name == "new step name\nstep line 1\nstep line 2"