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# Copyright (c) Meta Platforms, Inc. and affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
#
from dataclasses import fields, is_dataclass, MISSING
from libcst import matchers
from libcst._nodes.base import CSTNode
def node_to_matcher(
node: CSTNode, *, match_syntactic_trivia: bool = False
) -> matchers.BaseMatcherNode:
"""Convert a concrete node to a matcher."""
if not is_dataclass(node):
raise ValueError(f"{node} is not a CSTNode")
attrs = {}
for field in fields(node):
name = field.name
child = getattr(node, name)
if not match_syntactic_trivia and field.name.startswith("whitespace"):
# Not all nodes have whitespace fields, some have multiple, but they all
# start with whitespace*
child = matchers.DoNotCare()
elif field.default is not MISSING and child == field.default:
child = matchers.DoNotCare()
# pyre-ignore[29]: Union[MISSING_TYPE, ...] is not a function.
elif field.default_factory is not MISSING and child == field.default_factory():
child = matchers.DoNotCare()
elif isinstance(child, (list, tuple)):
child = type(child)(
node_to_matcher(item, match_syntactic_trivia=match_syntactic_trivia)
for item in child
)
elif hasattr(matchers, type(child).__name__):
child = node_to_matcher(
child, match_syntactic_trivia=match_syntactic_trivia
)
attrs[name] = child
matcher = getattr(matchers, type(node).__name__)
return matcher(**attrs)
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