name : brain_hypothesis.py # Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html # For details: https://github.com/PyCQA/astroid/blob/main/LICENSE # Copyright (c) https://github.com/PyCQA/astroid/blob/main/CONTRIBUTORS.txt """ Astroid hook for the Hypothesis library. Without this hook pylint reports no-value-for-parameter for use of strategies defined using the `@hypothesis.strategies.composite` decorator. For example: from hypothesis import strategies as st @st.composite def a_strategy(draw): return draw(st.integers()) a_strategy() """ from astroid.manager import AstroidManager from astroid.nodes.scoped_nodes import FunctionDef COMPOSITE_NAMES = ( "composite", "st.composite", "strategies.composite", "hypothesis.strategies.composite", ) def is_decorated_with_st_composite(node) -> bool: """Return whether a decorated node has @st.composite applied.""" if node.decorators and node.args.args and node.args.args[0].name == "draw": for decorator_attribute in node.decorators.nodes: if decorator_attribute.as_string() in COMPOSITE_NAMES: return True return False def remove_draw_parameter_from_composite_strategy(node): """Given that the FunctionDef is decorated with @st.composite, remove the first argument (`draw`) - it's always supplied by Hypothesis so we don't need to emit the no-value-for-parameter lint. """ del node.args.args[0] del node.args.annotations[0] del node.args.type_comment_args[0] return node AstroidManager().register_transform( node_class=FunctionDef, transform=remove_draw_parameter_from_composite_strategy, predicate=is_decorated_with_st_composite, )