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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"KeyError when using Rule keyword with step data tables or DocStrings","articleBody":"# Bug Report: \n\n## Environment\n- **OS**: Windows\n- **Python version**: 3.12.10\n- **behave version**: 1.3.1\n- **allure-behave version**: 2.15.2\n- **allure-commons version**: (auto-installed with allure-behave)\n- **allure commandline version**: 2.35.1\n\n## Description\nWhen using the `Rule` keyword (introduced in Behave 1.2.6) in feature files, `allure-behave` formatter throws a `KeyError: None` exception when processing steps that contain:\n1. Data tables (tables attached to steps)\n2. DocStrings (multi-line text enclosed in triple quotes `\"\"\"`)\n\n## Expected Behavior\nThe Allure formatter should successfully process scenarios under a `Rule` that contain steps with data tables or DocStrings, just as it does for scenarios without the `Rule` keyword.\n\n## Actual Behavior\nThe formatter crashes with a `KeyError: None` traceback when attempting to attach step data (tables or text) to the Allure report.\n\n## Steps to Reproduce\n\n### 1. Create a feature file with Rule and data table\n**File: `test/features/simple/tutorial.feature`**\n```gherkin\nFeature: showing off behave\n\n\tRule: Basic arithmetic operations\n\n\t\tScenario: Passing a table as a data through step\n\t\t\tGiven we have behave installed\n\t\t\tWhen we pass a table as a data through step\n\t\t\t\t| number1 | number2 | result |\n\t\t\t\t| 2       | 3       | 5      |\n\t\t\t\t| 4       | 5       | 9      |\n\t\t\tThen behave should be able to read the table\n```\n\n### 2. Create step definitions\n**File: `test/steps/steps_tutorial.py`**\n```python\nfrom behave import given, when, then\n\n@given('we have behave installed')\ndef step_impl(context):\n    pass\n\n@when('we pass a table as a data through step')\ndef step_impl(context):\n    assert context.table\n\n@then('behave should be able to read the table')\ndef step_impl(context):\n    pass\n```\n\n### 3. Run with Allure formatter\n```bash\nbehave -f allure_behave.formatter:AllureFormatter -o allure_result_folder\n```\n\n### 4. Observe the error\n```\nException KeyError: None\nTraceback (most recent call last):\n  ...\n  File \"allure_behave/listener.py\", line 147, in start_behave_step\n    self.logger.attach_data(uuid4(), step_table(step), name='.table', attachment_type=AttachmentType.CSV)\n  File \"allure_commons/reporter.py\", line 163, in attach_data\n    file_name = self._attach(uuid, name=name, attachment_type=attachment_type,\n  File \"allure_commons/reporter.py\", line 153, in _attach\n    self._items[last_uuid].attachments.append(attachment)\n  File \"allure_commons/reporter.py\", line 33, in __getitem__\n    return self.thread_context.__getitem__(item)\nKeyError: None\n```\n\n## Additional Testing\n\n### Works ✅\n- Simple scenarios under `Rule` (no tables/DocStrings)\n- Scenario Outlines with Examples tables under `Rule`\n- All scenario types WITHOUT `Rule` keyword\n\n### Fails ❌\n- Steps with data tables under `Rule`\n- Steps with DocStrings under `Rule`\n\n### Test Results Matrix\n\n| Scenario Type | Without Rule | With Rule |\n|--------------|--------------|-----------|\n| Simple scenario | ✅ Works | ✅ Works |\n| Scenario Outline with Examples | ✅ Works | ✅ Works |\n| Step with data table | ✅ Works | ❌ **Fails** |\n| Step with DocString | ✅ Works | ❌ **Fails** |\n\n## Root Cause Analysis\nThe issue appears to be in `allure_behave/listener.py` at line 147 (data tables) and line 144 (DocStrings). When processing scenarios under a `Rule`, the `last_uuid` is `None`, causing the attachment operation to fail when trying to access `self._items[last_uuid]`.\n\nThe `Rule` hierarchy creates a different context structure that the formatter doesn't handle correctly when attaching step data.\n\n## Suggested Fix\nThe `start_behave_step` method in `allure_behave/listener.py` needs to properly handle the context hierarchy when scenarios are nested under a `Rule`. The `last_uuid` should be correctly resolved even when scenarios are children of a `Rule` element.\n\n## Additional Context\n- The `Rule` keyword is a valid Gherkin construct for organizing scenarios\n- Behave 1.2.6+ fully supports the `Rule` keyword\n- This issue prevents using Allure reporting with modern Gherkin best practices\n\n## References\n- Gherkin Rule keyword documentation: https://cucumber.io/docs/gherkin/reference/#rule\n- Behave changelog (Rule support): https://github.com/behave/behave/blob/main/CHANGES.rst\n\n","author":{"url":"https://github.com/hemz10","@type":"Person","name":"hemz10"},"datePublished":"2025-12-01T07:58:28.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/886/allure-python/issues/886"}