# 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,
)
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